jse

That would certainly be a less expensive way to fix the problem and provided the fibers are in good shape, probably the most reasonable. The problem with the newer type clutch packs (I understand the latest packs are different) having both the steel plates at 2+mm's, when the thickest available aftermarket shim plate (1.6mm, although there is supposed to be a 1.8mm plate available) is substituted for one of the 2+mm plates, the pack ends up being too thin and then you run into the problem of the fingers being too high. This can result in slippage due to lessened pressure exerted on the pack and maybe the fingers bottoming out agains't the fully retracted servo cylinder. Jon

In the course of my previous career some years back, I had some contact with Evel in Northern California. I think he was living at the Flamingo in Las Vegas at the time. He personally struck me as a straight-up guy who didn't make excuses for his actions and took advantage of the cards life dealt him, not unlike his PR image. One of the last things you wanted to do was make a bet with him on the golf course..... Jon

You mentioned you had a TXT 320, so I'm guessing it probably is a 97' JTR320 (they were silver plastic in the States) with the Kokusan system in it. I think they had a DC rectifier and a voltage regulator, (both little black box type thingies) but no "relay", per se, for the fan. If it says "TRANSVAL 415" on it, that is the voltage regulator, if it has "LEONELLI SPAIN" on it, that's the rectifier, do you remember which one it was? Jon

I'd check for: 1. A poor ground. I wouldn't assume the ground is good if the capscrew holding the clips is tight, I'd take it apart and sand the clips and re-install. 2. A short in the system. I'd trace all the wires in the system and make sure there is no insulation rubbed off. It will usually be in a spot where you can't see it. Start at the stator and work upwards. If you haven't had the flywheel off since you bought the bike, you might be surprized at what you find. Unvented sidecases, especially those with plastic covers that may have compromised sealing, will literally suck water into them when cooled quickly (like in a creek). Jon

Just saw your post, so I went out to the shop and pulled a new clutch pack out of stock. Measurements were: 1.76mm, 1.76mm and the adjustment fiber plate (the one that goes in first) was 2.18mm. As I understand, the new clutches available will be a little different as they may be adjusted by the different (and available) shims like they used to be and not by the last fiber plate in the pack. I didn't measure the steel shims in the new pack, but I'm guessing they are 2mm plates (1.76mm+1.76mm+2.18mm+4mm=9.7mm). This pack may be different from yours so go by the condition on the fiber faces and if they are good, shim the pack to get the correct finger height and I would guess you'd be o.k. The 9.75mm measurement is important to maintain the correct relationship between the pressure plate and the basket plate so the spring exerts appropriate pressure. Jon

That would work just about as well as replacing shims as it wouldn't take more than a little off the fiber faces to slim down the pack. My buddy's 06' 300 Pro had the fibers swell a little, just enough to move the fingers down to about 14mm. He was sure he needed a new clutch pack, but replacing a shim made it good as new. The fibers were in excellent shape, but the measurements are so exact in the Pro clutch, it won't tolerate things too far out of wack. The cool thing about the Pro clutch is that it's fairly easily adjusted to suit one's riding style as far as engagement is concerned. Jon

Well, I could be wrong (which my wife would quickly assure me that it is NOT the first time...., but in my experience, the assembled clutch finger height, that is dependent on the operating pressure of the plate/Bellville spring, and the condition/relationship of the mechanical parts-not just the measured free thickness of the clutch pack outside of the clutch assembly-is a more relevant measurement. I find I get better results by setting the finger height as my "final answer", irregardless of what the free clutchpack measurement is. So, yea, I'd say try a .1mm thinner shim plate and see how the fingers are. Rarely, but sometimes the fiber plates will swell a little over time, which will expand the pack and drop the fingers down to the point where the clutch will be stiff at the lever. I did one this morning for a friend who rides Expert Class and is hard on clutches. It was easy to adjust and works like new. The Pro engines are quite simple, but quite precise. Jon

Spencer, That also is my experience. The clutch pack thickness is just an initial adjustment I can do to get me in the ballpark for the required measurement for the finger height. That "top hat" servo cylinder has a limited range of free movement before it runs into something (like just about everything else in an engine) and although, in operation, it does not move far, I like to keep it near the center range of motion, which seems to give me the smoothest emgagement. Jon

Other stuff for GasGas that might be helpful to you: http://www.trialspartsusa.com/tech.html Jon

Not necessarily, some packs came with first (inner) fiber plate as a thickness adjustment plate and the two steel plates were 1.6mm. There was supposed to be a 1.8mm plate available to adjust that type of pack for wear but we haven't been able to get them over here so far. The clutch packs are adjustable for thickness (which dictates finger height) so you should be able to substitute steel plates of other thickness' to set it to the desired pack thickness. The steel plates (or "shims" as they are sometimes called) come in 1.3, 1.4, 1.5, 1.6mm and supposedly the 1.8mm measurements and you can get them from your dealer. I've tried to discover a stable linear relationship between substituted change in plate thickness and change in finger height ("If I substitute a 1.5mm shim for a 1.4mm shim in the clutch pack, it will change the assembled clutch finger height "X" amount") but I haven't found one. It's a change shim, assemble clutch, measure finger height, swear and repeat process sometimes. Jon

I run a General Motors product (AutoTrac II transfer case fluid) in my 02' 280 Pro with good results and recommend it to riders with 02' to 05' Pros. The late models seem to do a little better with the DexronIII ATF, which has a little more "bite", as the Bellville spring in the clutch is a little thinner for lighter lever pressure. The ATF is about 7.5 weight and the Gas-Gas clutches seem to feel better with a lighter fluid. I change mine about 5-10 hours, or less, of use or after a tough or wet Trial. It's a little more critical to keep fresh tranny fluid in a Pro as the main crank bearings are lubed by the transmission oil. I also run a magnet type drain plug (like the lower crankcase plug) in the top sidecover to give extra protection from swarf. Jon

I think the last I heard he was living in France and didn't he marry Eddy Lejeune or Therry Michaud's Sister or something? I know he was deep into mountain biking and may have designed some bikes but I understand he had a Trials school and was involved in writing the book, "Observed Trials". It sure would be nice to see him again, the Master of the floating turn. I first met Bernie and his Dad at Donner in 1974 (he won the World Championship 5 years later) when he was a teenage squirt and at that age he was remarkable. We kept bugging him to show us how it did the things he did, but he didn't know exactly what he did, he said "just did them".

Sounds like a great idea, but I haven't heard of it yet. I looked in the 08' Owner's Manual and didn't see anything mentioned (I don't have the 08' parts manual yet so I couldn't scan the schematics) but I wonder if they aren't confusing it with the older design (like the "Edition" models) that have a shear pin in the shift racheting mechanism that would shear when the shift lever, with the engine in gear-under load, got thumped hard by a rock (something I'm good at). You would be stuck in whatever gear you were in but it would probably save a complete strip-down to replace bent shift forks. Jon

A little drag is generally normal in the Gas-Gas clutch and actually works to your advantage in that it keeps the driveline "loaded" so that you don't have a jerky clutch engagement when all the slack is taken out of the chain, gears, clutch plate fingers etc. Though it does make finding Neutral a pain when stopped or pushing the bike in gear out of the section with a dead engine (with which my riding talent level demonstrates all too often). I'd measure the clutch pack first before replacing it, the assembled pack should be about 9.75mm thick and the clutch fingers should be around 17/17.5mm in height above the basket hub (see: http://www.trialspartsusa.com/diagrams/Pro...12th%202007.doc ). The 03' uses an o-ring and seal on the servo cylinder post down at the clutch sidecover (the 02', like mine, has two o-rings) and if they were leaking I would guess you would probably see a loss of fluid in the M/C reservoir, unlike a leaking seal in the M/C, which would just pass fluid back up to the reservoir. Jon

Interesting. There's not much left to replace. Although simple, the first thing I'd check is the adjustment screw on the lever. Make sure it has a little clearance between it and the plunger (that goes through the rubber boot) that presses in on the piston. Look under the boot to make sure the piston returns back fully to the circlip, as sometimes the piston return spring that pushes back on the piston, inside the master cylinder, can be weak (rare on the newer bikes). If the piston does not come back to the circlip, the bleed hole to the reservoir is not uncovered and the system can't equalize. If the hose was leaking you would think there would be fluid somewhere. Make sure the fittings are tight and I would imagine you replaced the aluminum crush washers on the fittings when parts were replaced. I kinda doubt it's a porus cover but you might try some compressed air in the servo piston tower and spray a little soapy water around to see if you have any bubbles. You'll want to have the lever pulled in to close off the system and you'll want to clean and re-bleed to make sure you didn't get any water from the compressed air up in the hydraulic hose. Jon

Actually, laying the bike on it's left side is the best way. You don't have to drain the oil, as mentioned, but you'll find the plates and fingers line up better. With the bike straight up, it's easy to have the lower fingers on the clutch flop out a little by gravity and get hung up on top of the servo cylinder bearing plate as the sidecover is being put on. Just be careful when installing the sidecover and use your fingers to hold the special washer and thrust bearing up until the servo cylinder "top hat" end clears the fingers. Also be careful to align the pin on the waterpump with the slots on the crank bearing. I like to take the pump off and ziptye it against the pipe and when re-installing it, move the crank enough to have one of the slots line up with the lower waterpump capscrew hole and move the pin on the pump to also line up with the lower mounting hole. Cheers. Jon

My guess is that it's designated as a 2009 model. The new 09' models are usually available around October 08' on this side of the pond. Adam is testing a new lightweight frame with lots of carbon fiber goodies on it and tons of space around the engine to make it really easy to get at. Currently it's got a two-stroke in it, but the mountings appear to almost exact between two to four stroke from what I can glean from the photos. Sure whould make the various models easier to manufacture , and most of the chassis parts would probably fit both engines. If they use that frame, I would imagine the four-stroke could weigh just about what the current two-stroke comes in at, considering the prototype four-stroke has that magic name, "Magnesium", cast into the engine cases. One way or another, it will be different and appears to be totally focused, engineering wise, on Trials only. Jon

Andy, I just happened to run across this question today, try: http://www.trialspartsusa.com/diagrams/GAS...IS%20NUMBER.doc Jon

Good adivice, from my experience all the Gas-Gas Trials models come with the "fast", white, throttle tube (it has a slightly higher ramp which will pull more cable per degree of rotation) and a black tube works better for floppers like me. My 02' 280 has the Kokusan non-alternative ignition mapping so one of the ways I soften the throttle response is to run straight 110 race fuel, which has the effect of retarding the static ignition timing. The race fuel has a slightly slower flame front propragation (one of the ways it resists detonation) which results in a lower "IMEP" or "Indicated Mean Effective Pressure" (similiar to a lower static pressure at TDC during the ignition cycle). And, the "modification" is easily reversed. Here in the States, 91 octane is generally the best retail pump fuel we can get. I've spoken with several riders who have fit the Hebo flywheel and they all have been happy with the results. Jon

Good idea, I'll have to try a D34 in a 300. One of the things I've done that seems to help with the PHBL's is to drill the starter jet out to a #80 (.80mm or about .031") which makes my 02' 280 Pro start second kick in any weather. The stock starter jet is usually a #65 or #70 and is located at the bottom of the floatbowl at the end of the little brass tower with an o-ring on it. Jon

I think Blocky is right and the gears should be replaced as a unit. To keep it from happening again, be sure to take up slack in the kickstart lever to engage the racheting mechanism and use body weight to spin it over rather than just jab at the lever. I see a lot of riders kick at, rather than on, the lever and this will create quite an unnecessary shock load on the gears. Jon

Thanks! I have riders from all over the world contact me with questions and give me feedback on tips they have found on problems we've worked on together, so it's a two-way street and I, for one, have learned how creative and resourceful riders can be when faced with technical problems. Since we've started the Gas-GasUSA website a few years ago, I've archived over 3000+ answers to riders questions in eight different languages (I use translation software for simple answers and the answers on the website were only the first 84). It's really a lot of fun for me to do it and I've made friends all over the world, even helping a rider in Slovakia start a Trials club. I'm having more fun in Trials now than when I first started in 1971. Trials Central is an excellent forum and a great place to get good information or just make contact with like-minded people. I often refer riders here to follow the threads and get involved in order to expand their network of information resources. As a group, Trials riders are probably the best bunch on competition -oriented riders to be around, and I've been around just about all types. Cheers! Jon

Cool. I was wondering when somebody was going to do that. Some background on the videos: They have been put together, for many years now, by Dale Malasek and Jim Snell. Dale is the Gas-Gas Trials importer for the U.S. and Jim Snell (shown in the videos) is the parts importer here and both know just about more than anybody on this side of the pond when it comes to the Gas-Gas Trials and Pampera models. In the 80's Dale used to make excellent Trials videos through his company "Action Video" (I have the complete set and they are just about my favorites in my collection of about 450+ Trials videos) and he wanted to provide his customers with some good information on servicing the Trials model, so in the early 90's, he and Jim got together and made some VHS Gas-Gas Owner's Manuals (before DVD times...). A tape was included with each new bike sold in the U.S. (and still is) and updated when necessary and eventually switched to DVD format. Both Jim and Dale are past U.S. National Class Champions and Dale still competes on a regular basis. Cheers. Jon Stoodley GasGasUSA website tech advisor

Good advice. A lot of times (well, more than a LOT of the times) it's usually something simple that is easily overlooked, like a loose fitting on the trans breather or the breather hose down too low. The transmission case, essentially being a container of hot oil and air, will experience a vacuum condition when rapidly cooled, which is usually by water from a creek, and the water (and grit) will be sucked into the container through any available "opening" such as an ill-fitting gasket or loose fitting. I'll never forget a demonstration experiment in Chemistry class where we took a 55 gal. steel drum, heated it, then plugged the opening and sprayed it with cold water in order to watch it curl up into a crunchy ball of metal from the pressure differential. I've turned bikes into crunchy balls of metal since then, but it was due to my lack of riding skill, not pressure differentials. This is also why I've vented all my alternator covers from the early 70's on and have experienced few problems with corrosion in the flywheel/stator area. As I have an 2002 280 Pro, this is especially important as the cases and clutch sidecover are magnesium, not aluminum like the 03's on up (Raga's excepted, but they have a different coating on the surfaces) and are prone to corrosion if not properly maintained. Cheers. Jon

I've got a problem with my 2004 TXT 200, I keep getting coolant in the gearbox oil. I've re-built the water pump but the problem continued so I sent the pump up to gas gas and the've re-built it but the problem still continues. Is there another route for coolant get in there other than via the water pump. Any ideas anyone ? Hi! One possible, but often overlooked thing that might cause it: The cap overflow tube on the radiator has a black hose to draw off hot/excess coolant and if it is curled down over the top of the frame brace, when the the fuel tank is installed, the underside front of the tank can squeeze it off and pressure will build up in the system to the point here it is higher than the rated pop-off pressure of the cap. This will force coolant past the W/P seal and into the transmission case. Unusual, but a thing to watch on the Pros. Cheers. Jon