jse

Jim, as usual, is spot on and I'd follow his advice. If I think that the jetting is off a little (not unusual for a used bike) I like to fix that first and then go on to other possibilities, like the exhaust system, but starting at either end works. If you are careful when taking the manifold off, the gaskets can be re-used, although using new gaskets is always a better idea. Sometimes a razor blade will help ease them off without splitting. You can use a very light coat of gasket sealing compound on the old gaskets to avoid leaks. On the reeds, look for a rough, frayed tip at the outer ends. Also check as to how far the tips stand off from the sealing surface and if it's more than about .010/.015", I'd replace them. Boyesen dual-stage reeds work really well in this engine. Jon ps. Not to worry, there are no "stupid questions", you are going through the same process we all went through and we all realize it takes a little courage to ask in the first place.

I'd say you are running a little fat on the main, which is why you have to compensate for it by the lean needle clip setting. I'd try a #116 (possible #114) main, needle clip 2nd groove from top. The pilot is fine and even a #38 would work. Start with the fuel screw about 3 turns out and then adjust it for ambient conditions (quickly "blip" throttle from idle and adjust screw in/out to get best response). Don't worry if your best fuel screw setting is different from your buddy's identical bike, each engine is different. I like to adjust the float arms level with carb base with carb upside down. You can run 80:1, full-synthetic with no problem and you might want to check the reeds for any wear/damage. Cheers. Jon

I poked around in my parts box and, from the info on the kit, the 595C kit fits 97-04' clutch/brake. The 594C fits 04-07' Raga brake and 02-04' clutch. My guess is that they interchange, both being for the 9.5mm bore, DOT 3/4/5.1 fluid. The main thing is that you can't use DOT 3/4/5.1 with the mineral oil seal kits, but I imagine you could use mineral oil and DOT 5 (Silicone) with the kits with the DOT 3/4/5.1 seals (like the 594/595C). What all that blah blah means is I think you can use that kit with mineral oil with your bike. I could be wrong as I'm not sure of the difference in the 10' TXT/11' Raga M/Cs, but if it was my bike, I'd try it. Jon

I agree. The V-Mar adapter is like the rubber "donut" but a little longer and made from aluminum so you get a more positive seal. The dimensions of the carb/airbox boot area are a compromise in order to fit both the Dellorto and VHST/Keihin carbs. You can see the differences in spigot diameter, bell diameter and body length between the two types of carbs. Not usually a problem except for the confines of a Trials bike. The rubber "donut" adapter on the Dellorto seems just a little too short and flexible in some cases to make a solid, leak-free connection unless you are very careful and deliberate in installing the carb. I don't have that problem with my 2002 280 Pro as the airbox boot fits the Dellorto perfectly, the adaptation components started in 2003 with the VHST carb used just that one year but also allowed for the Keihin PWK. Hint: Install the carb/donut/airbox boot junction first and then lever the carb back into the manifold last. If you tighten the carb into the manifold first and then try to get the bell/donut back into the airbox boot, it can be an almost impossible task, in some cases, to get right. Jon

Ben, Be sure to very carefully inspect the gear set and shaft end where the split bearing rides. Those parts have the inner and outer "race" for the needles to roll on, so if those surfaces are damaged, you might run the risk of premature bearing failure for the new parts. Hopefully you've caught them early and will be o.k. This is the reason a rider shouldn't continue to use the transmission if a bearing failure is suspected as further damage will mean that not only the bearing has to be replaced, but both the gear cluster and shaft. Cheers. Jon

You didn't say how much your mate weighs. This might be a good time to change the fork oil and you can make some adjustments while doing that. You can make a slightly longer preload spacer (5-12mm, depending on rider weight) and add a little more oil, of a different viscosity, to each fork. The preload spacer is inside the fork at the top or sometimes the bottom of the spring and is usually a grey plastic tube. Those forks take 300cc's of 5-weight oil each and you could try 310 to 320cc's of 7.5 weight oil. The volume of oil affects the "oil level" in the fork, raising it. The oil level affects the last third of fork travel and the higher oil level will help prevent bottoming. The adjusters at the top of the fork fine-tune the damping but usually only in the "high-speed" mode ("high speed" as to cartridge piston movement, not bike speed), which is why most riders can't really feel the difference from the adjustment changes. They do work, just not the way most riders think they do. Jon

I'd check the jetting in the carb first. What jets and needle/needle setting do you have in the carb and what type of carb is it, Dellorto or Keihin? Did you buy this bike new or second-hand? The "melting foam" (I assume you mean the formed rubber insulators) symptom is interesting. The lower half of the engine usually runs cooler than the upper half. Jon

The head should normally be too hot to touch, the surface temp usually is around 150-170 F. from my experience. It has coolant running through it and usually is the hottest outside temp part other than the exhaust system.. Do you have any other symptoms? Jon

Penetrating oil will probably not reach the threads but may loosen the o-ring so might help. The threads should have oil on them already from the fork oil. Be sure to only tighten the top cap "snug", the o-ring seals the oil in, not the tightness of the cap and the cap is held tight by the upper tripleclamp. You may find the "drain plug" is actually the "base bolt" and fastens the cartridge to the lower leg. Don't forget the copper washer on that bolt when re-installing. Jon

The finger measurement refers to the distance from the inner clutch hub to the top edge of the "fingers" (how far the "fingers" are angled in or out from the inner clutch hub surface). A caliper is the easiest way to get an accurate measurement. The finger angle generally affects three things: how much pressure is exerted by the clutch spring, the mechanical advantage the fingers exert in relation to the pressure plate and the range of travel in clutch engagement. Jon

I run Castrol at 70:1 and have never had a problem. My guess is that most of the riders that run 100:1 have never built a professional race engine.... Jon

Zippy, I have no idea where the 550ml came from, undoubtedly a very dark place....... The factory seemed to kick that and a few other numbers around for a while, not sure why. The pre-Pros took 650/700ml and my 2002 Pro with the Mag cases takes about 360ml. I've found that about 425ml for the 2003 on up seems to work well, but I like to keep the level towards the top of the glass so 400 should also work well. The key is to keep the oil clean and moisture-free. Jon

My understanding also, except the 350 bore is chrome, not Nikasil. And Chuck's correct, 350 pistons are like hen's teeth to find here in the U.S. I think Bob Ginder at B&J has some special made now and then, but the OEM pistons/rings are very rare. Jon

Jim Snell just posted a new video on removing/replacing the clutch. Easy if you follow his tips: http://www.youtube.com/watch?v=eucYaEA-Cfc&feature=youtu.be Jon

And air bled from cartridge. Jon

You'll need about 270-290cc's per leg. You'll do fine. Jon

The process is essentially the same, with minor exceptions, except the Marzocchi forks must be set by oil level and the GasGas forks can be set by volume of oil. If Sawtooth is not experienced, it's a good idea to have a friend who is experienced stand by to avoid beginner mistakes. We have all started as beginners. Jon

I made these tools for bleeding cartridges in forks. They have different thread sizes to fit a variety of cartridge rods. The tool is threaded to the top of the rod and then the cartridge can be stroked to purge air. The tool also makes it easier to pull out the cartridge rod to install the top cap. Jon

Yes, both legs. You might consider making this simple tool to hold the spring down when removing/replacing the top cap. That's a bleed tool where the top cap would be screwed on. Jon

As I remember, the seals are standard for the 40mm GG forks, steel or aluminum. The Marzocchis need to have the oil set by level, not volume and for the steel tubes, I set the level 180mm down from the top of the tube. If you like them springy you can use 5 weight but most riders do well with 7.5 weight. Jon

" Just bought the bike and the guy who sold it to me said that to start it I have to not rest my foot on the lever first and not to take up the slack in the lever before kicking it, he said just to kick it straight off." This guy is a sponsored rider, at least uninformed and at best, just ignorant of Trials bike engines. They have massive flywheels that don't take kindly to movement when at rest and that's why its a big shock to the racheting mechanism when the kickstart lever is stomped on. You can start them that way, but not for long. You need to take up the slack and then put some weight on it to get that flywheel mass moving. Start it like a Harley, not an RM125 and you'll be fine. It was common for TY350 owners to snap the long forged steel kickstart by stomping on them. Jon

samo, You probably have the standard PHBL Dellorto on your bike. If you stand on the side of the bike and look at the carb, you'll see two screws, the one in the center of the carb body is the idle speed (it raises and lowers the slide slightly) and the one to the left (towards the manifold, not the airbox) of that screw is the fuel mixture screw (it fine tunes the low-speed mixture). The idle speed screw adjusts the idle speed by raising or lowering the slide a slight amount. The fuel mixture screw makes slight adjustments to the low-speed air/fuel ratio and in combination with the pilot jet, affects throttle response up to about 1/8th throttle opening. Contrary to what a lot of riders will tell you, there is no "standard" setting as that fuel screw adjusts the carbs ability to maintain the necessary mixture according the that particular engine's need and the outside weather conditions that affect the air/fuel ratio (temp, barometric pressure, humidity etc.). If there was a "standard" setting that worked for all engines, there would be no need for it to be adjustable so it would just be sealed off. The quick way to adjust the fuel screw is: engine warm, "blip" (quickly open and close throttle) the engine and adjust the fuel screw in or out in 1/4 turn increments until you get the best throttle response. The setting you end up with will be different for conditions, such as, the setting for a cold, dry Winter day will probably be different than for a hot, humid Summer day. The technique for setting an air screw is essentially the same. Jon

The reason I asked is that there are two measurements on that diagram, the measurement for the clutch pack and the measurement for the finger height with the clutch assembled. I've generally found that the finger height to be the better one to use as it is a more accurate representation of component relationship under actual operating conditions. When using the 2002 fiber plates, they had a problem with swelling (material was changed in later clutch packs) and this may be contributing to your problem, especially if you used the clutch pack measurement to set the adjustment rather than the assembled measurement. Assuming you have appropriate clearance at the lever adjustment screw/ M/C plunger in order for the piston to fully retract, another issue may be that the lip on the M/C piston is worn and there is a slight taper in the M/C bore from normal use (if the M/C is the same one that came with the bike over 11 years ago). If that is the case, the piston wil not seal in the bore until it travels past the enlarged part of the bore at the beginning. A M/C rebuild kit will solve that problem. I also have a 2002 280 Pro, since new, and have used the GM AutoTrac II for years with no problems. A slight amount of drag is normal and for most riders, actually makes clutch modulation under difficult conditions easier as it keeps the driveline "loaded". Jon

When you say "in spec", what measurement are you using? Jon

Welcome, Alan. Let us know when you get it running. Trials bikes are surprizingly durable. Cheers. Jon