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The 10/42 combo is by far the most popular on this side of the pond. Stock is 11/42 and in some cases, 11/41, which is a little high geared for the lower class riders and tends to get them where they want to go a little sooner than they are ready for.... I run an 11/44 ratio on my bike, which is somewhat in between and works well for me. Jon

Very impressive project and a real labor of love. Jon

I've used the Wossner piston and have not had any problems. It would be an updated item for the JTX. Jon *forgot to add, ring end-gap for the GasGas is usually set at .1mm per inch of cylinder bore, so your REG will probably be about .25mm rather than .35mm.

Go to: http://www.trialspartsusa.com/tech.html and download the 08' parts manual. It usually has the wiring harness schematic and that should help as to routing. Jon

Nice work, you're really going to enjoy riding your project. For me, working on my bikes is almost as fun as riding them. Jon

Matt, Jitsie is pretty solid in their designs so I would imagine it would be an improvement. If you try one out, I'd be interested in your report. It would make the conversion a lot easier. Jon

Years ago we did dyno testing of coatings and found a flat black finish gave about a 15% reduction in internal heat. To reflect external heat source, a light color, like white, worked well. Jon

It is a common fix and solves the problem. I've fixed a few friends silencers by cutting and welding in a plate and surface sanding the welds, and if done well it's had to tell it's a repair. The top shock bolt secures the silencer hanger/tab and the tab can be spaced out using about 3-6mm of stacked washers. The shock bolt is secured by a Nyloc nut so if the bolt threads do not engage the Nylon after the washers are installed, you'll want to use some Loctite in the nut. If the plate is put on the outside of the muffler, you'll need to space out the silencer even more as there will be less clearance due to the thickness of the plate. I agree, considering the topic, participant restraint has been surprizing! And, a little scarey......... Jon

Hi Matt! It doesn't always happen but I've seen a couple of split manifolds using the PWK in the Dellorto manifold. Like I mentioned in our e-mails, I haven't seen the Jitsie adapter in person but I would wonder about the necking down of the 28mm to the 26mm and if that would negate some of the advantages of using the PWK. If there is not too much of a venturi effect, it might be a good way mount the Keihin. Jon

From your description, I'd say the engine needs to be disassembled and inspected. Sounds like serious engine damage. Jon

That's a good idea. You might have to bend the stand out a little to clear the spokes but I can see the advantage to it. Jon

The bike is a TY350 I set up for new riders to try at events when they don't have a bike to ride yet. Although it has many updates and mods and goes, stops and handles well, it is purposely made to look "rough" with old, beatup plastic on it so the rider does not have a heart attack when, not if, they drop it in the rocks. The stand was quickly made from scrap so cost was nil. The "stealth" TY has started a LOT of new riders in Trials over the years. The thick wall tubing does not bend easily like the stock TY does. Approximate spec.'s: 20mm OD, thick wall tubing and 1/4' plate first straight length of stand-19.5cm second lengh-11cm third length-6cm

Several riders I know use them and are quite happy with the results. Like RichT says, smooth power delivery and less stalling (be sure to adjust your idle speed with the bike in gear). I've even made some weights (with less than half the std. add-on flywheel weight) for some Pro level riders and they have transferred them to their new bikes. Jon

I'll get the good camera out tomorrow and try to take some photos and measurements for you. Jon

I made one for a TY350 loaner bike I let new riders try (much safer than letting them borrow the Pro) and I just took one off my other TY and used it as a pattern. Ask to borrow one from a friend to give to the fabricator to use as a pattern. Jon

If this is a Pro, there is info as to indexing the kickstart under: GASGAS PRO TECHNICAL INFORMATION GASGAS Pro Engine Technical Bulletin UPDATED JUNE. 08 2010 If this is not a Pro, but the earlier design (I didn't see it mentioned) there is info as to how to set up the Kickstart in another part of the Tech section. There is a very thin washer that goes on the outer end of the shaft (not on the inside) and it's easily lost when the cover is taken off. A rider could replace it accidently with another washer that is slightly thicker and this would bind the shaft. Make sure you use a new GG sidecover gasket as the gasket also acts as a spacer and leaving it off and thinking sealer will work will result in binding of the shaft. Jon

You could dress the surfaces with fine emery. The tabs on the fibers only move a small amount. If you took too much from the surfaces it could lead to accelerated wear due to excessive movement of the tabs within the "finger" posts. Jon

For several years now, the GG Pro clutches have come with two 2mm steel and two fiber plates of the same thickness. The third fiber plate was thicker and the thickness was chosen at the factory to adjust the pack thickness upon assembly (this thicker plate is always put in the clutch assembly first). This was different from the older types that had three fibers of the same thickness and the steel plates were chosen to adjust the pack width. The steel plates came in 1.3, 1.4, 1.5, 1.6 and although I've been told they are available, I've never been able to get them, a 1.8mm. Your problem lies in the fact that you already have 2mm plates so the adjustment "shims" will not do you much good at this point as you want to increase the width of the pack a little. Since most Trials riders are packrats and save just about everything just in case they "might need it later" (o.k., I'm the only one who does that....) you might ask around to see if anyone has an old clutch pack they took out. Provided the old pack is in halfway good shape, you could then measure that thick fiber plate to see if you can replace one of the thinner plates with it. I know it sounds a little Mickey Mouse to do it this way (I've tried it and it worked fine) but you can always go the different leverage levers and S3 sidecover later. Jon

As an aside to the discussion, a friend asked me about "normal" clutch rattle yesterday and here is part of my reply: "My guess is that the rattle is mainly due to the straight cut gears on the hub and primary gear (and the low mass of the new type engines is less of a harmonics absorber). There is a little amount of lash that is normal and pulling in the clutch lever causes drag on the hub which keeps the gear teeth in contact. Crankshafts do not rotate at a constant, smooth rate near idle and there is a little speeding up and slowing down due to the ignition and compression cycles and this causes the primary gear teeth to move back and forth against the clutch hub gear teeth (rattle). Straight cut gears are usually used in high performance applications as they transmit power much more effeciently than spiral cut gears. Spiral cut gears are much more quiet as there is more than one tooth in contact with the other (the main tooth and a little bit of both the forward and backward teeth). The spiral cut gears, however, exert a lot of side force (one gear shaft is being pushed forward and the other shaft is being pushed backwards) which puts a strain on the shaft bearings and uses up torque forces." Jon

That is unusual. Possibly, if the bike was on it's side when the cover was installed, one of the fingers is caught on the wrong side of the top hat flange. I'd also check the caged needle hub bearings, there are two sets seperated by a wire circlip. Jon

O.k., that makes sense. I just can't figure out what the performance parameters of a compression test with the throttle closed would be. Regardless, you've made ME happy.... I agree with tankygsy, in that it should do something even with 70 PSI. It would be hard to start but would at least run crappy I'm guessing. Maybe it's possessed and you need a priest............ What'ca think, try using something like WD40 as a starting fluid? Jon

Charlie, compression testing (and comparison to spec. readings) is always taken with the throttle WFO. Jon

Charlie, 70 PSI sounds pretty low and you should have about double that. You might need to pull the top end and check the ring gap to see how much wear you've got. Jon

I gave Chris the TC link so maybe we can get his expert advice in person. He really has come up with some excellent modifications for a number of bikes and his present Fantic, which he still owns and rides, is a prime example. Jon

Great! I'd love to see how it comes along. Cheers. Jon