MCC Forum

Technical Topics => Bike Help => Topic started by: Paul K on February 26, 2017, 01:53:17 pm

Title: GS500 Classic Trials Project
Post by: Paul K on February 26, 2017, 01:53:17 pm
Well, I've managed to create some room in the garage since the arrival of a new bigger shed so work on the project can continue  :) .  The GS500 engine just about fits in the GS250 frame.  The GS450 swinging arm fits the frame a treat (same swinging arm bearings and same width at the pivot tube).

(http://i1095.photobucket.com/albums/i468/rattonshaw/1%20RHS%20view%20resized.jpg)

(http://i1095.photobucket.com/albums/i468/rattonshaw/2%20LHS%20view%20resized.jpg)

Next task is to fit the DR650 front forks with their new machined steering stem, install and align the front and rear wheels, then check the sprocket alignment to ensure the engine is sitting correctly.  If it's not, then it's out with the grinder and the welder again.

Watch this space for news on progress, though, don't hold your breath, this is a long term project and has to be fitted in with everything else I'm doing.
Title: Re: GS500 Classic Trials Project
Post by: Jason Potts on February 27, 2017, 06:39:48 pm
That looks superb Paul. That really is snug. Did you have to make all new mounts or did some lign up to get you started?
Title: Re: GS500 Classic Trials Project
Post by: Paul K on February 28, 2017, 10:09:40 am
I had to fabricate all new mounts.  The GS250 engine is a bulky unit and the engine is not far off the same external dimensions as the GS500 engine, but they're not exactly the same.

The engine is tight; to adjust the valve clearances involves removing two mounting bolts and tilting the engine forward to allow the cylinder head cover to be removed.  As the valves are checked every 6,000 miles (I think), it won't happen too frequently for a trials bike.  Say once every 5 or 6 years?

(http://i1095.photobucket.com/albums/i468/rattonshaw/3%20Front%20RH%20view%20604pxW.jpg)

(http://i1095.photobucket.com/albums/i468/rattonshaw/4%20Front%20LH%20view%20640pxW.jpg)

Title: Re: GS500 Classic Trials Project
Post by: Paul K on March 16, 2017, 02:51:02 pm
So hereís the next stage in the project. New steering head bearings and the yokes installed with the new steering stem, new swinging arm bearings and the wheels temporarily in position. Ignore the rope round the steering head; that's just to stop the forks fully extending while on the trolley. The sharp-eyed will notice the top nuts are missing because you can see the tops of the fork springs.
(http://i1095.photobucket.com/albums/i468/rattonshaw/1%20Wheels%20in%20640pxW.jpg)

(http://i1095.photobucket.com/albums/i468/rattonshaw/2%20Wheels%20in%20Rside%20552pxW.jpg)

The forks were stripped and the spacer above each spring removed for research purposes. The forks have as standard about 250 mm (10 in.) of travel, which is far too long for me (short legs) and would give too much ground clearance.  I reckon I need about 175 mm (7 in.) of travel so that involves a shorter spacer above the springs and a new tubular spacer below the spring in the damper tube (a bit difficult to see this spring in the image). Effectively, this should reduce the travel and lower the forks. The final dimensions of these four spacers (two for each leg) will be worked out when the bike is fully weighted with engine, etc. The fork length at rest will also be influenced by what length rear shocks are available in order to maintain the required rake.
(http://i1095.photobucket.com/albums/i468/rattonshaw/Forks%20schematic.jpg)

Currently, the approximate dimensions are working out at wheelbase 1,400 mm (55 in.), rake 27 degrees, ground clearance 230 mm (9 in.). Chain clearance and sprocket clearance are tight, but acceptable.
(http://i1095.photobucket.com/albums/i468/rattonshaw/3%20Chain%20clearance%20378pxW.jpg)

(http://i1095.photobucket.com/albums/i468/rattonshaw/4%20Sprocket%20clearance%20378pxW.jpg)

What I would like is some advice on the suspension travel other members are using on any big twin, e.g. Cheney Triumphs.
Title: Re: GS500 Classic Trials Project
Post by: Jason Potts on March 17, 2017, 07:41:12 pm
That's looking very tidy Paul. Does the standard tank fit or are you fitting something else?
Title: Re: GS500 Classic Trials Project
Post by: Paul K on March 17, 2017, 08:40:28 pm
Well, not quite sure at the moment. I bought a GS250 tank, thinking it would fit the frame. However, the tank is from a GS250T (cruiser-style with a pear-drop shape  tank) whereas the frame is a GS250X (road bike style with a coffin-shape tank, I think that's the description). The two tanks are not interchangeable  :( .

So the option is to get busy with the hammer on the tear-drop tank I have to make it fit, or try and buy a coffin-shape tank and hope it doesn't foul the engine. But and a big but, I haven't seen a coffin-shape tank anywhere  :( . And I have been looking, for example, I had to buy the GS450 swinging arm from a Dutch website.

I could have an alloy tank made up, but I'm trying to keep within a reasonable budget  :-[ .

Title: Re: GS500 Classic Trials Project
Post by: Paul K on April 22, 2017, 08:37:18 am
Work on the project progresses again now that the Lands End trial is over  :) ; I had to devote some time to prepping the XR400 for the trial.

The footrest assemblies with integral gear lever pivot (left side) and brake pedal pivot (right side) have been welded up and bolted to the frame. The folding footrests I bought from Pride & Clarke online; good quality too. The problem with the footrests is the mounting points either side of the frame are not symmetrical, hence the two bolts on one side are above the pegs whereas the two bolts on the other side are below the pegs. This creates a small area in which to mount the pegs to avoid one peg being higher than the other. That took a lot of time with cardboard templates   :( . I had a local guy weld the footrests onto the mounting brackets; my MIG welder doesn't have the power for thick steel  :( .

The gear lever operates the selector rod remotely through a linkage. The reason is that the GS500 gear selection works backwards due to the standard bike having rear-set footrests. A couple of rose-joints and M6 threaded rod allow the remote gear lever to operate the gears in the normal up/down sequence  8) .

Next task is making a bracket for the DR400 rear master cylinder to attach the rear subframe and sourcing the basis for a brake pedal that sweeps above the foot rest  :-\ .

More pictures when I get a chance.
Title: Re: GS500 Classic Trials Project
Post by: Paul K on November 13, 2017, 02:58:41 pm
The projects been on a slow burn for a while  :( .  I've since made new engine mounts that allow the valve clearances to be adjusted without removing some of the engine bolts.  The gearbox lower mounts were remade and welded in the frame by local friendly welder. I've included spacers so that the engine can be shifted sideways should I have got the chain alignment not quite right  ::) .

On the rear brake; the bracket for the DR400 rear master cylinder is welded onto the frame, a torque anchor is welded onto the swinging arm and I've got a brake pedal (still to be modified).

On the intake side, I've bought a K&N filter (for a GS500) and I will fit two long aluminium tubes between the cards and the filter. The benefit is two-fold in that the filter now sits under the seat and, I'm theorising, the longer intake tract will give more torque at the bottom end, hopefully  :-\ .  Some silicon tube connects the carbs to the aluminium tubes.

A plate for the electronics will be mounted above the battery and in front of the rear mudguard.  It's getting pretty full under the seat by now  :o .

The exhaust is planned to be a modified 2 into 1 GS500 system that I have.  It'll run under the right side of the engine and be protected by the engine skid plate.

Engine bars are planned because the engine is wide and the cases are thin. The only downside is that the bike's getting heavier each time I look at it.  But what the heck, If I can't manage the main trial, there's always class 0  ;D .

Title: Re: GS500 Classic Trials Project
Post by: Paul K on May 11, 2018, 10:23:18 am
An update on progress to date.  After the Lands End Trial and various other commitments, I found some time to work on the project  :).

The electronics plate is installed under the seat and accommodates the ignition module, rectifier/regulator, starter solenoid and indicator relay.  The prop stand switch and associated relay are ditched.  The GS500 wiring loom has now been modified to suit the new location of the electronics and the shorter run from the headlamp to the electronics plate.  The loom also includes a fused live feed from the solenoid up to the handlebars for a route holder and battery charging. A new starter/battery cable has been a pain; the original cables are too short and measure up at 13 mm2 csa, but that seems to be unavailable in the UK so I've gone for a bit beefier 16 mm2 csa cable.  a bit chunky, but it's very flexible so should go in with no headaches.

The K&N air filter with the long aluminium tubes fits nicely under the seat with a bracket to support the weight and stop the carburettors being pulled off.  All looks very tidy under the seat, though, not enough room to store tools :( .

The rear mudguard brackets are tack welded onto the frame and the seat base is sorted now that the position of the rear mudguard is fixed.

The fuel tank is installed with a few modifications, using a hammer, to clear the cylinder head cover and to allow the forks a larger turn angle.

Header pipes are welded up and installed, running under the right side of the engine.

Brackets are made up for the side panels (to be aluminium sheet) and are to be welded on the frame and fitted with M5 rivet nuts.

When I work out how to efficiently load photos, I'll post some. For now, it's back to the garage?  Nah, going for a cup of tea  ;)
Title: Re: GS500 Classic Trials Project
Post by: Paul K on May 15, 2018, 06:10:11 pm
Here are some photos of progress to date.

(https://farm1.staticflickr.com/960/42086294542_700467c959_b.jpg)
Fig. 1 K&N air filter (GS500) and inlet tracts with blue silicon hose

(https://farm1.staticflickr.com/831/27261976007_39d6817055_b.jpg)
Fig. 2 Electronics plate with all the electrical gubbins

(https://farm1.staticflickr.com/906/42086294732_16e804b0c8_b.jpg)
Fig. 3 DRZ400 rear brake master cylinder and brake pedal before modification

Title: Re: GS500 Classic Trials Project
Post by: David (tufty) White on May 15, 2018, 09:57:57 pm
I'm enjoying watching the progress. 
Title: Re: GS500 Classic Trials Project
Post by: Jason Potts on May 16, 2018, 07:23:03 pm
Me too

Can we get a panned out pic with the tank on  :D
Title: Re: GS500 Classic Trials Project
Post by: Paul K on May 17, 2018, 07:00:44 am
The project is at the back of the garage surrounded by the usual junk, but first chance I get, I'll add some photos of the petrol tank.

The seat is underway; the base is cut out of 6 mm plywood and I have the seat foam from a Suzuki DR650 to modify.  I'm still working out the best method of securing the seat to the frame while there is a load of spares and clothes on the bike, during a trial that could get in the way.
Title: Re: GS500 Classic Trials Project
Post by: Paul K on May 21, 2018, 06:38:12 am
The fuel tank and material is not the best shape and type for the intended purpose of the bike, but the mass of tubes that comprise the spine of the frame limit the choice and the budget does not extend to a custom made aluminium tank :( .

(https://farm1.staticflickr.com/978/42201639432_22c0d3968f_z.jpg)
Fig. 1 Fuel tank with panel beaten indentations for the fork stanchions  ::)

(https://farm1.staticflickr.com/912/41346880805_52005b42bc_b.jpg)
Fig. 2 Increased steering lock due to the indentations  :)

(https://farm1.staticflickr.com/947/41346880795_259b5267c1_b.jpg)
Fig. 3 Underside of fuel tank

The exposed steel is where the tank has been indented to accommodate the right ignition coil and the right side of the cylinder head cover. The pencil marks on the left side of the tank mark out where the tank is too close to the left side of the cylinder head cover so a bit more denting to happen. The front of the tank may have splayed outwards due to the attentions of the hammer so I may have to attempt to squeeze the two sides together somehow ;) . The fuel tap is going to be relocated to the rear of the tank. Currently, the fuel tap sits above the left spark plug; not a good idea :o !

(https://farm1.staticflickr.com/981/41346880665_9b410e71dc_z.jpg)
Fig. 4 Rear mounting, fuel tank

I couldn't locate a new rear rubber mounting for the tank so had to make one up from some rubber sheet and a steel spacer I had knocking about.
Title: Re: GS500 Classic Trials Project
Post by: Paul K on May 23, 2018, 07:02:54 pm
More photos of progress, particularly a view with the tank on.  Note that the inside of my house looks nothing like as bad as the inside of my garage.

(https://farm1.staticflickr.com/878/41581669614_f8b04932e2_b.jpg)
Fig. 1 General view of right side

The tank looks like it's running downhill  :-[, though, I think that's to do with the angle of the frame on the trolley.

The engine bars are now fabricated. They're constructed from GS500 bars, but modified to suit the frame.  Essentially, the only bit that didn't get modified on the right bar was the front bracket. The vertical bars are from the frame's pillion footrest tubes.  Nothing's going to waste  :).  That's not going to be a straight-through exhaust; just working out where the silencer is going to be installed; probably uphill at a 30 degree angle.


 (https://farm1.staticflickr.com/982/42256442222_e93a3e6f35_z.jpg)
Fig. 2 Engine bars, right side

The engine bars will, hopefully, save the cases when the bike is dropped  :-[.  The header pipes run real close the front down tube and the engine case. A bash plate will protect the pipes and the sump.  The brake pedal can be glimpsed, currently held on with a pair of mole grips, awaiting modification.

(https://farm1.staticflickr.com/894/41581669214_c19646fe56_b.jpg)
Fig.3  Engine bars, left side

Less mucking about involved with the left engine bar  :); only had to alter the position of the rear bracket and weld a box section to the bottom tube of the frame.  The gear lever is shown without the linkage to the gear shaft; this linkage has still to be fabricated.

Ideally, I'd like to discard the sprocket cover, but it houses the clutch release mechanism.  As it is, I've cut away a lot of the interior webbing to allow the mud and crap to drop through  ;).

Still have some questions on what is the optimum ground clearance and optimum front suspension travel for MCC trials  :-\. Anyone got some opinions?


Title: Re: GS500 Classic Trials Project
Post by: Stephen Bailey on May 24, 2018, 01:16:52 pm
I have used Suzuki Petrol tanks on two Velocette Trials bikes.. Sprayed the appropriate colour.. and decals... An excellent choice.
Title: Re: GS500 Classic Trials Project
Post by: Jason Potts on May 27, 2018, 07:28:32 pm
Quote
Still have some questions on what is the optimum ground clearance and optimum front suspension travel for MCC trials  :-\. Anyone got some opinions?
I've chatted with Rick on a few occasions regards what's the best solution for LDT's. The best solution is a light weight modern trail bike like a beta alp or a serow etc. However, like me Paul I think you favour the unusual and more so the home built so it's going to be a compromise. For best stability you want your centre of gravity as close to the centre line of your wheel axles as possible. If your C of G is too high the bike will feel top heavy. If you'd started with a bantam or some other little 2stroke engine then its not too detrimental to stability if this is hoyked up high as it doesn't weigh much. You've chosen a GS lump so I'd get this as low as you dare because it's going to wiegh some. I'm in the same boat as you Paul, I'm about to start a class A project using a 600 sidevalve engine. I'll be using the standard 1953 forks though, not much travel or damping. But as Rick says, we do this for the challenge so where's the fun in making it easy. You have your 400 for that  ;)

Rick keeps telling me, just build it, ride it and then modify it as you go. You won't get it 100% right first time. He told me his bantam got developed over 10 years and I totally respect that.
Title: Re: GS500 Classic Trials Project
Post by: Stephen Bailey on May 28, 2018, 03:47:01 pm
Only need a few inches of ground clearance for Classic Reliability Trials. I managed OK for quite a few years on a Girder Rigid Velo MAC.
Title: Re: GS500 Classic Trials Project
Post by: Stephen Bailey on May 28, 2018, 03:47:56 pm
Are you sure you need the engine guards? Looks like it might be getting a tad heavy.
Title: Re: GS500 Classic Trials Project
Post by: Paul K on May 29, 2018, 07:40:05 am
For best stability you want your centre of gravity as close to the centre line of your wheel axles as possible.
I've got no alternatives for the position because the engine is so tight in the frame.

I'm about to start a class A project using a 600 sidevalve engine. I'll be using the standard 1953 forks though, not much travel or damping.
You need to start a new thread  ;).

Rick keeps telling me, just build it, ride it and then modify it as you go. You won't get it 100% right first time. He told me his bantam got developed over 10 years and I totally respect that.
10 years! I haven't got that much time.  Or patience  ::).  If I could modify anything at this stage, it would be fit an 18 inch rear wheel without a cush-drive (lighter and will take an MT43) and fit an alloy tank.  But that's not going to happen; yet.

Are you sure you need the engine guards? Looks like it might be getting a tad heavy.
Yes, you do need engine guards for the GS500. It's a very wide engine with thin-wall cases. I've seen posts on the internet where the bike has been dropped, the case damaged, causing the alternator to get chewed up, or even the crankshaft damaged. See the pictures below of the left side of some poor guy's engine  :(.

(https://farm1.staticflickr.com/878/41702877294_159a1d8337_z.jpg)
Fig. 1 Rotor damage due to a GS500 being dropped

(https://farm2.staticflickr.com/1727/28552904208_65c010e63c_z.jpg)
Fig.2 Coil damage due to a GS500 being dropped
Title: Re: GS500 Classic Trials Project
Post by: Jason Potts on May 29, 2018, 09:04:11 am
Hey Paul, I didn't mean change the engine position in your frame. You change the engine position when you fit a 21" wheel, fit longer forks and raise the rear by fitting longer shocks or changing the mount positions etc. This all has the effect of increasing ground clearance but also raises the engine up too. With a light engine this is not too bad but a heavyweight will make your bike feel top heavy.
Title: Re: GS500 Classic Trials Project
Post by: Paul K on May 29, 2018, 09:32:54 am
Ah, got you.  That's my motivation in getting as low a ground clearance as I can get away with.  Because the frame is a fixed, i.e. I'm not moving the position of the headstock, I can only lower the bike by shortening the fork suspension travel and/or raising the fork stanchions in the yokes.  Hence the question, what's the optimum suspension travel I can have on an MCC trial? Examples of fork suspension travel are REH forks 165 mm, Ceriani CONV38rev3 (trials) forks 170 mm, XT500 forks 195 mm and RE Bullet 130 mm.
Title: Re: GS500 Classic Trials Project
Post by: Stephen Bailey on May 29, 2018, 10:10:54 am
 "That's my motivation in getting as low a ground clearance as I can get away with".

Neat.
Title: Re: GS500 Classic Trials Project
Post by: Paul K on July 11, 2018, 09:44:16 am
Had a bit of time after the Scatter Rally to work on the project.  Gear change linkage is now sorted and dummied-up.
(https://farm2.staticflickr.com/1786/28469455437_5e8423b675_b.jpg)
Fig. 1 Side view of gearchange

The geometry is not strictly correct :(.  The adjustable link should be a tangent with the foot pedal and with the remote lever.  Therefore, an angle of 90 degrees would be formed between the adjustable link and the foot pedal and remote lever. However, when I marked up the holes for drilling, I was hanging over the top of the frame in a confined space (too much junk in the garage).  Ended up with an angle more like 45 degrees.  Anyway, if I'd got it correct, the link would've been too long to fit.  It'll do to change gear so that's all that matters ;).

(https://farm2.staticflickr.com/1786/42434429955_067fe91a40_b.jpg)
Fig.2 Aerial view of gearchange

Still got to work out a way to keep the crap off the rose joints.  Perhaps some self-amalgamating rubber tape would do?

Could be a postponement for a while; I've done my sciatic nerve so major discomfort  :-[
Title: Re: GS500 Classic Trials Project
Post by: Paul Wheatley on July 16, 2018, 06:01:05 pm
For rose joint covers, you might find something suitable here:

https://simplybearings.co.uk/shop/Bearings-Rod-End-Bearings-Rod-End-Covers/c3_4544_5467/index.html
Title: Re: GS500 Classic Trials Project
Post by: Paul K on July 17, 2018, 11:51:40 am
Those covers work out too expensive for me; £15.92 plus the postage :o.  The two rose joints only cost me £5.02 including the postage.  I'll see what else I have knocking about in the garage.
Title: Re: GS500 Classic Trials Project
Post by: Paul K on July 20, 2018, 10:22:55 am
Well, I made a start on moving the petrol tap to the rear of the tank from the centre.  What I thought was a steel reinforcing plate at the rear (fig 1), and into which the tap would be installed, turned out to be a copper blanking plate.  After drilling two holes in the copper plate, a difficult look inside revealed weld-nuts on a separate plate. 

Off came the copper blanking plate, which was sealed to the tank with lead, to reveal all.  Bugger!  The two weld-nuts were rusted to hell and were intended for a tap with wider bolt spacing.  No way I can utilise these weld-nuts.  Drilling out two spot welds, released the weld-nuts plate, leaving a mass of holes (fig 2). 

(https://farm1.staticflickr.com/833/29653879518_6e21da9241.jpg)  (https://farm2.staticflickr.com/1781/43525406181_fac913ce9c.jpg)
Fig 1 Before the truth is revealed                                              Fig 2 After the debacle

Solution?  Fabricate a new steel plate with two rivet-nuts (centres 35 mm apart) to fit inside the tank, then install a 2 mm steel plate on the outside of the tank to create a clean surface for the petrol tap.  The next problem is bonding the outside plate to the tank because the mating surfaces are not perfectly flat and the bonding product must be petrol resistant.

Leading is the obvious solution, but I donít have the skill or facilities for that.  After much internet search and a telephone conversation with a very helpful guy at Loctite I deduced this.  Some anaerobic gaskets are petrol resistant, but need a very flat surface.  Silicon gaskets are not petrol resistant.  Some epoxy bonding products are petrol resistant, but can be brittle.  My conclusion is to experiment with some Chemical Metal, manufactured by Plastic Padding.  If a test piece works out ok, then Chemical Metal it is unless someone can recommend a more suitable product.
Title: Re: GS500 Classic Trials Project
Post by: Stephen Bailey on July 26, 2018, 08:34:42 am
Why not soft solder or braze a plate on?
Title: Re: GS500 Classic Trials Project
Post by: Paul K on July 27, 2018, 09:08:43 am
Good point.  The problem is that I don't have the equipment for that process and there's no-one local that I know will put a naked flame to a petrol tank, no matter how clean.  Don't know why not  ;D. So if an alternative is available, I'll go for that.
Title: Re: GS500 Classic Trials Project
Post by: Stephen Bailey on July 27, 2018, 10:32:31 am
It was clean enough to drill... :)
Title: Re: GS500 Classic Trials Project
Post by: Michael Leete on July 27, 2018, 11:42:04 am
Not far from you http://findit.lutontoday.co.uk/company/438362906423297 (http://findit.lutontoday.co.uk/company/438362906423297)

As well as rads they have done two tanks for me. Soldered one on my Dellow and welded one on Austin Seven.

Michael
Title: Re: GS500 Classic Trials Project
Post by: Paul K on July 28, 2018, 12:21:22 pm
Thanks Michael; I'll look into them, they're not far from me.  I'm currently awaiting a reply from the ThreeBond Technical department on their product ThreeBond TB1184, though, soldering is probably going to give a stronger bond.
Title: Re: GS500 Classic Trials Project
Post by: Stephen Bailey on July 28, 2018, 06:36:06 pm
Yes it really is, considering the vibration and flex that will happen to it.
Title: Re: GS500 Classic Trials Project
Post by: Paul K on July 31, 2018, 09:46:00 pm
Had to tackle a job Iíve been putting off for a while; removing the front engine bolt that is seized in the crankcase.  The GS500 engine is prone to this problem due to all the crap that gets thrown up from the front wheel and the electrolytic reaction that occurs between the steel bolt and the alloy crankcase.  If left to progress too far, the corrosion expands sufficiently to break off the lug from the crankcase.  Youíre pretty well stuffed then :(.

(https://farm1.staticflickr.com/933/43770245601_1be90f4e2a_b.jpg)
Fig. 1 Front engine bolt seized in crankcase

Fortunately, the bolt doesnít contact the crankcase for the whole width of the engine, just the lug at each end.  The first thing to do was remove the middle section of the bolt so I could deal with each lug separately.  That process involved drilling through the bolt at two points (I couldn't get a grinder in the space), then very gentle use of a chisel to remove a 25 mm section.

(https://farm1.staticflickr.com/937/28834057377_2769265de1.jpg)
Fig. 2 Underside showing where bolt is to be divided

Next, cut off the exposed parts of the bolt, drill along the length of the bolt at each, collapse each part of the bolt, then gently tap out with a punch :-\.

(https://farm1.staticflickr.com/853/43770245411_177efcc909.jpg)
Fig.3 Engine bolt cut and drilled


Crankcase cleared of bolt; a very big sigh of relief :D!!

(https://farm1.staticflickr.com/854/28834057267_1b49537fec.jpg)
Fig. 4 Engine bolt removed and crankcase still intact

The remains of the bolt is now a collection of short pieces.

(https://farm2.staticflickr.com/1813/43722121442_2951cd5712.jpg)

Fig. 5 Remains of engine bolt

Petrol tank is at the repairers; thanks Michael.


Title: Re: GS500 Classic Trials Project
Post by: Paul K on August 08, 2018, 06:26:12 pm
I could do with some advice .  I'm almost in the position where I can strip the project down and paint the frame. Total headache time  :-\!  I want to brush paint the frame with a paint that will give me the most resilient finish; I'm working to a budget here (apparently)!  Powder coating is out; I don't think this is the most suitable medium for this bike, mainly as I might end up welding the odd bracket here and there.

I've had a trawl through the internet, but haven't come up with a definitive solution.  There are products from Manor Coating Systems, from POR15, from PJ1, yacht paints, etc.  There are different primers and top coats.  My head's spinning  :'(.  I could do with some advice based on practical experience.  Oh, and the colour has to be blue  :D

And to add to the quandary. I have the aluminium alloy yokes that need painting silver, or polishing, then coating in a lacquer.  I know I could just polish the alloy yokes to a lovely finish, but I'm not renowned for cleaning bikes so that finish would soon dull to a corroded flat.

I'll service my bikes to the nth degree and replace iffy parts, but life's to short for cleaning; takes up valuable riding time.

Anyway, any suggestions on paint?
Title: Re: GS500 Classic Trials Project
Post by: Simon Woodall on August 09, 2018, 09:07:30 am
Hammerite?
Title: Re: GS500 Classic Trials Project
Post by: Paul K on August 09, 2018, 12:06:35 pm
I've never managed to achieve satisfactory results with Hammerite; that could be down to me  ::)
Title: Re: GS500 Classic Trials Project
Post by: Alastair Queen on August 09, 2018, 02:37:59 pm
I realise this is probably unprofessional, not the done thing, contrary to the sagest of advice, etc...probably a something-ist as well, but....I suggest looking at the paints Lidl sell?  They do an 'anti-rust' paint which I have found to be very difficult to remove...even with a too-powerful pressure washer...unlike other chassis paints, 'ammerite, etc.

They also used to sell aerosols, but with lidl, like Aldi, the stock problem is, one has to 'wait' until the offer comes round again?  Might be worth popping into one's local store, see if they have a ny tins left? Colour may not be an option, but, hey.....it's either, protection, or pretty? Take's yer pick eh?

Baufix is the maker, I believe?
Title: Re: GS500 Classic Trials Project
Post by: Stephen Bailey on August 09, 2018, 05:53:15 pm
Use Cellulose. Still available. Quick drying. Fairly corrosion resistant. Sorted. :)
Title: Re: GS500 Classic Trials Project
Post by: David Sharp on August 11, 2018, 07:28:43 pm
A few years ago I used Japlac enamel paint with really good results on a Matchless frame and oil tank with the best results being achieved by making sure the tin had been kept in a warm place. (Shouldn't be a problem this time of year). This way the brush marks disappeared to leave a lovely gloss finish.
More recently I've used Rustoleum paint, again with really good results and easy to use. I don't think you'd be disappointed with either of these and a much better choice than Hammerite where no two batches are manufactured the same-fact!
Title: Re: GS500 Classic Trials Project
Post by: Paul K on August 14, 2018, 06:35:15 am
I collected the fuel tank from Auto Radiators of Luton.  Well pleased with the result :).  The new plate I fabricated for the petrol tap, I fitted with two counter-sunk, stainless steel, M6 rivet nuts.

(https://farm1.staticflickr.com/938/43102677105_94702bd2b0.jpg)   (https://farm2.staticflickr.com/1772/43960189672_02bf2a8211.jpg)
Fig 1 Blanking plate soldered over previous tap aperture                Fig 2 New petrol tap plate soldered into position

Iíd recommend Auto Radiators for any tank or radiator repairs.  They had loads of stuff in for repair, including petrol tanks for a Ford Capri and an old military Land Rover.  Interestingly, they sealed the insides of petrol tanks with POR15.  Theyíre at 141 Portland Road, LU4 8AY, if you need them.

Iím still looking into the paint for the frame.  Thanks to everyone who came up with suggestions; all been very helpful.
Title: Re: GS500 Classic Trials Project
Post by: Stephen Bailey on August 14, 2018, 12:01:41 pm
As regards the paint..... Make sure it is petrol proof.
Title: Re: GS500 Classic Trials Project
Post by: Paul K on August 15, 2018, 07:22:17 am
Paint decision time :-\.  I've ordered some Rust-Oleum CombiColor in cans for the frame (blue) and the engine bars (black).  According to the data sheet; this product serves as a primer and top coat all in one; and it can be applied on bare and manually derusted steel. The preparation instructions state remove rust scale, loose mill scale, loose rust and loose coatings by scraping and wire brushing; sand intact coatings to roughen the surface slightly.  So on paper it looks good :).

The cellulose paint would've been a good choice for suitability; the application was the drawback. I didn't want to use aerosol  cans because the paint spray mist goes everywhere and my garage is small and full of other stuff, including bikes.  I'd have to cover a lot of stuff up :(.

The Aldi/Lidl products can be good, but as stated earlier, if you need another can, you can be a long time waiting. Their product is manufactured by Beaufix so there are places selling it on-line.

I was talking to my local paint supplier and the guy reckoned that Hammerite was not as good as in the past; I got the impression that probably all the good ingredients, that would be the pathogens and carcinogens, had been removed. International, another good manufacturer had been bought up by Dulux and the name put in mothballs.
Title: Re: GS500 Classic Trials Project
Post by: Alastair Queen on August 15, 2018, 11:51:34 am
International, another good manufacturer had been bought up by Dulux and the name put in mothballs.

Ooooh! International moth balls?    :)
Title: Re: GS500 Classic Trials Project
Post by: Stephen Bailey on August 15, 2018, 09:27:47 pm
International still do paint. (Marine applications).
Title: Re: GS500 Classic Trials Project
Post by: Stephen Bailey on August 15, 2018, 09:31:32 pm
And Yes... STV International, do make Mothballs..... :)
Title: Re: GS500 Classic Trials Project
Post by: Stephen Bailey on August 15, 2018, 09:32:36 pm
Incidentally, Why did you go for Blue and not Black?
Title: Re: GS500 Classic Trials Project
Post by: Paul K on August 17, 2018, 07:18:08 am
I like the colour blue :D.  The blue is also more in keeping with Suzuki models.  Similarly, red for Honda and green for Kawasaki. Black is in keeping with classic British bikes.
Title: Re: GS500 Classic Trials Project
Post by: Paul K on August 18, 2018, 07:34:46 am
I don't like yellow.  Perhaps it's a wasp thing, the winged variety, not the wheeled variety. The tank and mudguards are/were going to be silver  :-\
Title: Re: GS500 Classic Trials Project
Post by: Stephen Bailey on August 20, 2018, 08:46:07 pm
Black is easier to repaint. :)
Title: Re: GS500 Classic Trials Project
Post by: Paul K on August 21, 2019, 05:32:38 pm
The project is back on the go with some help from my granddaughter.  Finally dummied-up the important bits, i.e. engine plates, dummy engine, rear wheel spacing, petrol tank, then dismantled the lot.  Painted the frame and engine plates with with Rust-Oleum CombiColor in blue, and painted the top and bottom yokes in silver with a couple of coats of lacquer.

No photos of getting the engine in the frame Iím sorry to say, but the technique was to raise the engine, using a Felco chain hoist, then fit the frame to the engine.  The engine can be lifted by hand, just about, but manoeuvring the thing is a recipe for skinned fingers at best :(.  However, all was not well; two of the sump bolts at the front of the engine are rubbing the frame; bugger :-\.  New set of engine plates fabricated and the engine sits nicely, but itís a real tight fit.

Rear wheel installed to check the sprocket alignment using a laser.  Fortunately, all appears to line up; engine centred, rear wheel centred.  Relief al round ;).

(https://live.staticflickr.com/65535/48593250492_8e12b09c63_b.jpg)

(https://live.staticflickr.com/65535/48593106866_0606ffc56c_b.jpg)
Title: Re: GS500 Classic Trials Project
Post by: Jason Potts on August 23, 2019, 06:59:59 am
It's looking very nice Paul.

Paint the tank silver. Be very similar to greeves colours now that you have gone with a blue frame.  8)
Title: Re: GS500 Classic Trials Project
Post by: Paul K on August 31, 2019, 11:07:50 am
Exactly my thoughts.  It might even convince some people that the tank is a lightweight aluminium tank  :).  I'm also looking at some way of using another colour, or colours to make the tank appear smaller; perhaps stripes, or a pattern in a darker blue to give a visual misconception.  I've had a trawl on the internet, but nothing to inspire :-[.  But silver will be the dominant colour.
Title: Re: GS500 Classic Trials Project
Post by: Paul Wheatley on August 31, 2019, 12:41:08 pm
It's looking like it will be potent off-road machine.

Bearing in mind the title of the thread, I couldn't help noticing that the rear tyre seems to be of a type that doesn't comply with the MCC tyre regs...  ;)
Title: Re: GS500 Classic Trials Project
Post by: Paul K on August 31, 2019, 03:41:21 pm
No worries about conforming to the regs.  The tyres are both Continental TKC80 :)
Title: Re: GS500 Classic Trials Project
Post by: rick howell on September 01, 2019, 07:25:08 am
I'm also looking at some way of using another colour, or colours to make the tank appear smaller; perhaps stripes, or a pattern in a darker blue to give a visual misconception.
In a similar way to the "graduation" of blackness (a sort of shading) on some vehicle window glass? In dots or squares or diamonds of your darker blue - even a pixellation effect - darker towards the bottom of the tank?
I have a '60s Norton and the 3 gall tank has a "crease" along both shoulders, front to back, which just catches the light in a subtle way, changes the silver paint visually and so makes the tank less bulky.
I guess the same effect was achieved (plus the image of speed) by Yamaha's "speed stripes", Triumphs "scallops" and even BR's '50's new diesel multiple units image using "speed whiskers".
Or how about Dazzle Camouflage (see Wikipedia's page)? It's all smoke and mirrors!.....now there's an idea.
Whatever, it's coming along nicely, Paul. :D
Title: Re: GS500 Classic Trials Project
Post by: Stephen Bailey on September 01, 2019, 06:15:57 pm

I'm also looking at some way of using another colour, or colours to make the tank appear smaller.

Why?
Title: Re: GS500 Classic Trials Project
Post by: Paul K on September 02, 2019, 07:14:46 am
I have a '60s Norton and the 3 gall tank has a "crease" along both shoulders, front to back, which just catches the light in a subtle way, changes the silver paint visually and so makes the tank less bulky.
I guess the same effect was achieved (plus the image of speed) by Yamaha's "speed stripes", Triumphs "scallops" and even BR's '50's new diesel multiple units image using "speed whiskers".
Thanks, I'll look into the Norton colour schemes.  Less bulky appearance is what I'm after and the project tank is a similar shape to the Norton style.
Title: Re: GS500 Classic Trials Project
Post by: Paul K on October 25, 2019, 10:05:06 am
Wiring now nearly completed :).  The loom is now recovered in a non-adhesive plastic tape and any new connectors soldered on.  Fortunately, I was able to use the majority of the GS500 harness, just cut a section out of the spine area to shorten the overall length of the loom and shorten a few other parts.  Solder and heat shrink sleeving used, no crimped joints yet.

(https://live.staticflickr.com/65535/48956951976_f25ac821fe_z.jpg)
Headlamp birds nest :(

(https://live.staticflickr.com/65535/48957139112_4dbeb59f55_c.jpg)
Electrical panel top view

Rear brake is installed and bled; master cylinder nice and accessible :).

(https://live.staticflickr.com/65535/48957139107_a4002cf5eb_c.jpg)
Electrical panel side view

The battery is totally dead and just in place to work out cable lengths.  Intake pipes push the air filter back from clashing with the frame tubes.
Title: Re: GS500 Classic Trials Project
Post by: Stephen Bailey on October 25, 2019, 03:49:19 pm
Possibly waterproof all the connections now...Ö...
Title: Re: GS500 Classic Trials Project
Post by: Paul Wheatley on October 26, 2019, 06:38:49 am
I can't help thinking - will the front wheel (+ mudguard) clear the exhaust when the front forks are compressed? I had a problem with my Royal Enfield when I fitted a trials tyre to the front wheel and needed to lift the mudguard just half an inch to get side clearance. It looked fine until I compressed the front springs then tried to steer....the mudguard clouted the exhaust and would lock the forks off to one side.   
Title: Re: GS500 Classic Trials Project
Post by: Paul K on October 26, 2019, 03:07:47 pm
I had the exact same concerns so during the R&D stage, I installed the forks and front wheel in the frame without the springs.  By fully compressing the forks I could deduce where the header pipes could and couldnít go.  All good until, at a later stage, I had to fine tune the position of the engine and extend the header pipes.  However, Iím pretty sure I checked again with the forks fully compressed :-\.  At least, I hope so :-\.  Might be a pretty short mudguard if Iím wrong ;).

As for water-proofing the connections, the standard Suzuki multi-way connectors will be ok with some grease on the pins :-\
Title: Re: GS500 Classic Trials Project
Post by: Jason Potts on October 26, 2019, 04:41:52 pm
It's looking good Paul, this is by far and away my favourite thread on this site. Keep posting, I can't wait to see this finished.

 8)
Title: Re: GS500 Classic Trials Project
Post by: Paul K on October 29, 2019, 05:41:49 pm
Been tinkering in the garage again.  The OEM throttle cable worked out about 160 mm too short, which is strange as the OEM clutch cable seems to fit ok ???.  Anyway, after dismissing the idea of knocking up some mechanical linkage that would connect the OEM cable to the carburetters, I bought a cable kit from Venhill.  Quality parts and a good price :).  As an example, a brass nipple that costs a few pence from Venhill is charged a couple of quid from sellers on ebay :o.  And cable adjusters are silly money on ebay :o.

In the end, I cut the OEM throttle cable and only used the inner and outer wires and a brass nipple from the kit.  All the adjusters, I re-used from the OEM cable.  I thought Iíd have trouble getting the inner wire through the PTFE liner in the outer cable, but I cut a clean end with no frays and assembled the parts :).  It was so cold in the garage, I soldered the brass nipple onto the inner wire indoors :-\.

(https://live.staticflickr.com/65535/48980733138_37f98dc72c_n.jpg)
Finished throttle cable :)

Next up was installing the front master cylinder and slave cylinder.  Iíve installed new seals and dust seals in both.  Iíve found the only satisfactory method to remove the pistons from the slave cylinder is to pump the brake lever and gently tease the pistons out.  Alright, brake fluid spills out, but stick the cylinder in a tray and itís all good :).  The circlip in the master cylinder was a bit of a problem and involved filing my circlip pliers to make them fit the circlip and the confines of the recess.  It means a new needle file, but canít be helped.

The front brake is a pain in the backside to bleed >:(.  I reckon that's because there is a long loop of hose that rises above the master cylinder, which, I think, traps air that canít be shifted by pumping the brake lever :(.  Thinking ahead, I clamped the master cylinder in the vise, laid the hose and slave cylinder out as horizontal as possible and bled the brake.  Later, I put the slave cylinder on the floor below the master cylinder and left it for a couple of days for any air bubbles to pass into the reservoir and out of the fluid ;).

(https://live.staticflickr.com/65535/48981478097_e6a86528be.jpg)
Master cylinder installed Ė new seals :)

(https://live.staticflickr.com/65535/48981293256_391c04ea7f.jpg)
Slave cylinder installed Ė new seals :)
Title: Re: GS500 Classic Trials Project
Post by: Paul K on November 13, 2019, 06:10:06 pm
Been pottering in the garage again.  Been calculating what length rear shocks to fit that will give me a suitable front fork rake and a suitable seat height, hence the wooden shocks in the photo.  Rear shocks at 360 mm eye to eye gives the bike a 29 degree rake and means I can put my feet on the floor (though that is sitting on only 15 mm thickness of towelling).  Ground clearance is approx. 235 mm (9.25 in.)
(https://live.staticflickr.com/65535/49060697682_9dc1812ae9_c.jpg)

Paul W, you were correct in your frightening comment on the mudguard, I checked the gaps again with the forks fully compressed.  Yes, the mudguard hits the header pipe :(, which is why the mudguard is missing.  The clearance will be ok if I make a new bracket, or fit the mudguard under the bracket instead of above the bracket.  So, all is not lost :).
(https://live.staticflickr.com/65535/49059963948_79e30ba5f4_c.jpg)

I weighed the bike on a set of bathroom scales while it was out.  The front comes in at 70 kg (154 lb); the rear at 80.5 kg (177 lb); total 150.5 kg (331 lb)   Dry weight that is and without the silencer, which is approx.. another 2 kg.  Not too bad, considering thereís not much scope for weight saving ::).

Though the brakes are bled, Iíve got hydraulic fluid weeping from some of the copper washers under pressure.  I think the washers are just crap so theyíll need replacing :(.
(https://live.staticflickr.com/65535/49060843647_3aae88d9d1_c.jpg)

The speedometer is mounted so I can still see it with a route box installed on the handlebars.  The panel for the warning LEDs is fabricated and just awaiting the LEDs once Iíve sorted out what wires to solder to each other. 
(https://live.staticflickr.com/65535/49059963923_b2b386cc8a_n.jpg)

Any advice on shocks would be appreciated.  Iíve looked at Hagon, Betor and NJB Shocks.  Iím on a budget here so Ohlins and the like are totally out.
Title: Re: GS500 Classic Trials Project
Post by: Tony Bishop on November 14, 2019, 05:01:59 pm
Hi Paul,

Looks rather tidy if a tiny bit heavy but as you say there is not a lot to be done from that perspective.
NJB shocks have quite a good reputation particularly at the price and would probably work out considerably cheaper than Hagons.
Don't forget that you are checking the seat height with the suspension rigid so allow for some shock compression when you sit on the bike. I would imagine NJB would be able to give you some indication on the amount of compression you would achieve based on your weight.
Title: Re: GS500 Classic Trials Project
Post by: David (tufty) White on November 14, 2019, 06:28:15 pm
Have a look at Shock Factory.

They do a range of excellent units from simple emulsion all the way up to remote reservoir.  They'll also make them to your specs too.

http://www.shock-factory.co.uk
Title: Re: GS500 Classic Trials Project
Post by: Jason Potts on November 14, 2019, 08:10:15 pm
I have a brand new (still in the packaging) pair of JAWA 350 shocks and a brand new (still in packaging) pair of MZ 250 shocks that I wont be using.

will sell for 40 quid per pair plus post.

Jawa are 325mm between centres
MZ are 380mm between centres.
Title: Re: GS500 Classic Trials Project
Post by: Paul K on November 14, 2019, 10:21:52 pm
Have a look at Shock Factory.
http://www.shock-factory.co.uk
Thanks David, I did, but they'll blow the budget :o.

I have a brand new (still in the packaging) pair of JAWA 350 shocks and a brand new (still in packaging) pair of MZ 250 shocks that I wont be using.
Jawa are 325mm between centres
MZ are 380mm between centres.
Thanks Jason, but the lengths are unsuitable.  325 mm will probably give a rake of over 30 degrees; 380 mm will mean I'll be on tip toe.  I think there might be problems with the spring poundage as well; those shocks are meant for single cylinder two-strokes and my bike is a twin cylinder 500 four stroke.
Title: Re: GS500 Classic Trials Project
Post by: Paul K on December 10, 2019, 04:13:26 pm
Finally made a decision on the rear shocks after an informative phone conversation with Hagon.  Iíve now got 370 mm eye-to-eye shocks with medium damping and 18 kg springs :).  Having settled on that dimension for the rear shocks, I finished the assembly of the forks by tightening each damper-rod Allen bolt and filling with 10W fork oil.

The final fork assembly involved knocking up a couple of tools ::).  The first tool was to hold the damper rod while I tightened the Allen bolt at the base of the fork slider.  The second tool was to measure the oil depth in each leg.  The damper-rod tool was a cut-down bolt (27 mm across the flats) welded to a 3/8 in. drive socket that was no longer any use (cracked it down one side doing something I shouldnít have tried to do ::)).  The oil-depth tool was fabricated from some m4 studding with washers and nuts attached; the bottom nut is set at 164 mm.

(https://live.staticflickr.com/65535/49198833463_acbe37ebf4_c.jpg)
Tools worked a treat ;D.

Also finished is the warning lights panel.  Those LEDs are bright so Iíve run some 400 grade carborundum paper across the outside to give a frosted finish.  Hopefully, Iíll keep my night vision when they illuminate :-\.  A couple of diodes are hidden in the loom so I can use one warning light for left and right indicators.

(https://live.staticflickr.com/65535/49198833448_585315dc0d_n.jpg)
Warning lights panel front view

(https://live.staticflickr.com/65535/49198833453_922147554c_n.jpg)
Warning lights panel rear view

I was going to fit the rear shocks, but gave up because it was so cold in the garage, and raining outside :(.  A cup of tea seemed a better idea ;).
Title: Re: GS500 Classic Trials Project
Post by: Stephen Bailey on December 10, 2019, 08:13:15 pm
Are you on time fer the Exeter?
Title: Re: GS500 Classic Trials Project
Post by: Paul K on December 13, 2019, 06:13:43 pm
The project's not on time for anything.  It'll just get finished when it's finished.  I never did put a finish date on the project; too much stress.  I just fit in the work as and when I have the time.  Might be nice to do the MCC Scatter Rally 2020 on it, but that's in June so that seems pretty close.
Title: Re: GS500 Classic Trials Project
Post by: Paul K on March 07, 2020, 08:04:11 am
Done some more work on the project; this time fabricating the seat.  Fortunately, the rear sub-frame is flat so I cut a piece of 6 mm thick plywood to shape.  To allow for the rear mudguard, a few layers of plywood are glued to the rear end, then shaped to fit the profile of the mudguard.  The seat foam is from a Suzuki DR650, cut to the shape of the plywood base, then the gaps filled in with offcuts of the foam.  The bread knife and a wood saw worked well for cutting the foam :).

(https://live.staticflickr.com/65535/49629504591_716c956ec7_c.jpg)

Black vinyl is used for the cover.  I did toy with the idea of stitching pleats in the top of the cover and stitching the corners so asked my 12 year-old granddaughter, who has a sewing machine, if sheíd take the task on.  A pretty firm ĎNo!í on that request :o.  So plan B kicked in.  The foam is glued to the plywood with contact adhesive and the vinyl cover placed over the foam.  The foam does look real grubby, but it is 28 years old.

(https://live.staticflickr.com/65535/49628985498_1e7cb92d33_c.jpg)

To attach the vinyl cover, the plan was to use galvanised staples, but the plywood is so hard, it bent the staples :(.  That meant I used contact adhesive and woodscrews.  The bracket at the rear of the base attaches the seat to the frame by two 5 mm screws.

(https://live.staticflickr.com/65535/49629775347_a4fd709a2e_c.jpg)

It feels comfortable, though, whether itíll still feel like that after an hour or more is to be seen :-\.
Title: Re: GS500 Classic Trials Project
Post by: Paul K on March 28, 2020, 10:53:58 am
Having some time on my hands since Iím self isolating from Covid-19 due to my age, I set out to come up with an answer on how to tune the silencer.  The bikeís fitted with a Supertrapp silencer, part number 358-1719.  For those not familiar with Supertrapp, the silencer is equipped with a stack of 3 inch discs, the quantity of which can be adjusted to affect engine power and noise.  The exhaust gases pass radially across the outer edges of the discs.  To quote the manufacturer, ĎFewer discs reduce sound levels, more discs increase sound levels.  Fewer discs increase low-end torque and richen the fuel mixture.  More discs increase sound levels, increase top-end power and lean out the fuel mixture.í  So there you go ;).

I fitted this silencer on a previous project and managed to reduce the engine power by about 8 BHP (about 15% if I remember correctly) :-[.  There were other factors involved on that project such as using 2 into 1 header pipes, increased header pipe bore.  All a load of guesswork :(.

This time round I decided to be a bit more scientific about it.  Surely, one of the factors in compatibility would be the pressure drop across the two different silencers?  Exhaust gases going in are resisted by the internals of the silencer, consequently, higher pressure in than out.  So if I can measure the pressure drop across the original Nexus silencer, then match the Supertrapp silencer to that pressure drop, I should be reasonably close? ???

I came up with the rig below.  A manometer from plastic hose, containing coloured water, each end plugged into the opposite ends of the silencer.  Compressed air injected through a sealed wooden plug (in the blue hose), then note the differing levels on the water. 

(https://live.staticflickr.com/65535/49707252736_8b18585c7b_c.jpg)

It took a few dummy runs to get the trigger action correct for a sustained reading on the Nexus silencer originally fitted to the engine.  Pull the trigger too fast and the water levels bounced up and down, then the air reservoir ran out of air before the levels became stable.  Did a few runs and came up with a difference of approx. 140 mm between the two water levels.  (Thatís approx. 0.2 psi.)

Substituted the Supertrapp in  the rig and repeated the procedure.  After a few runs and adjusted with six discs and the end disc in place, I got a difference of more or less 140 mm between the water levels ;D.
(https://live.staticflickr.com/65535/49706717543_8e61bd8142_z.jpg)

Factors that affect any useful result are 1) I had no idea what the air flow through the silencers was and 2) Air flow through the silencer dropped off pretty quickly as the reservoir emptied.  Will all this result in an equivalent performance when the engineís pushing the bike along at normal road speeds?  I have absolutely no idea  ???! 

Everyone take care and stay healthy.
Title: Re: GS500 Classic Trials Project
Post by: Tim Kingham on April 02, 2020, 10:13:40 am
I dont have a problem with the supertrap discs and as we found out on the Egli Racer its dead easy to fit the disc pack to another silencer bodyhttp://www.oldracer.co.uk/img/gallery-pics/thumbs/pic6.jpg
Title: Re: GS500 Classic Trials Project
Post by: Paul K on April 04, 2020, 08:20:18 am
Good to hear that about the Supertrapp technology on a racer.  One guy told me that the Supertrapp was old technology; mind you, he was selling me a Motad exhaust system.  Would that Ďother silencer bodyí be that aluminium billet that you bored out?

Not much been going on in the rebuild what with the lack of parts :(.  Iíve had to order stuff online for home delivery; things like engine oil, fuel hose, hose clamps, wet & dry paper, masking tape and paint.  Most of its due next week so mucked about with a few small things.

Got the tank to fit correctly.  The underside was sitting on the cylinder head cover, but that was soon solved with a bit of hammer work ;).  Checked the tank doesnít leak by putting some fuel in.  The petrol came out a horrible brown colour so the tank needs flushing ::).  Cleaned and adjusted the gear change.  Tightened up all the engine mounting bolts.  Made some stainless steel pivots for the foot pegs out of some socket head screws.

(https://live.staticflickr.com/65535/49734041707_e91b4502a7_n.jpg)

(https://live.staticflickr.com/65535/49734041742_93ae95b598_c.jpg)
Side stand needs a tweak and chainguard still to be fabricated.

(https://live.staticflickr.com/65535/49734041747_092aa0336b_c.jpg)

Ground clearance is more than adequate and the seated and riding positions are comfortable.  I can also get both feet (in shoes) flat on the floor :D

Roll on next week.
Title: Re: GS500 Classic Trials Project
Post by: Tim Kingham on April 04, 2020, 02:18:32 pm
I put some back paint on my white mudguard on my DR as at night when standing on the rests the headlight reflected on the guard and stopped me seeing the section ground detail
Title: Re: GS500 Classic Trials Project
Post by: Paul K on April 04, 2020, 05:41:09 pm
I put some back paint on my white mudguard on my DR as at night when standing on the rests the headlight reflected on the guard and stopped me seeing the section ground detail
Thanks for sharing that :(
Title: Re: GS500 Classic Trials Project
Post by: Jason Potts on April 05, 2020, 08:24:30 am
That's looking very nice now Paul. Would this be eligible for class F?

I read your email by the way, one thing that has always peaked my interest is three wheelers. Think we chatted about this at Tamworth once.

Could you do a bit of a write up on your 2cv powered one please. Or just thoughts on three wheels in general. Or thoughts on 2cv and mods required to get them trials ready.

Would love to know what mods George has done to his Rialto. I seem to recall you can use motorbike tyres on them too. Did you go down this route?

Cheers
Jason