jse

The clutch has nothing to do with the gear selection so I wouldn't worry about that. The 96 is totally unlike the Pro and there is a spring-loaded arm with a roller (under the clutch) that locks the shift drum in gear and neutral (the roller drops into the gaps on a star-shaped collar on the end of the shift drum). Look for a weak spring on the roller arm and/or worn bushings in the arm/roller assembly. The parts can be replaced without splitting the cases. Jon

On the 96', you'll probably want to start at 3 or 3 1/2 turns out. Jon

Well, actually they use that method to re-seat the tire bead on the rim after it has come loose, which is often with the low pressures and nasty rocks they ride on (kinda like the Fantic front tubeless they tried once). Course, you could try using that method to pop the bead off, but it might be a little dangerous....... Jon

Fuel turned off, plug grounded away from the head, throttle wide open and several kicks in sequence? 148 seems a little low but not enough to cause the problems you describe I would imagine. On the subject of crank seals, you have two, inner and outer, on the alternator side as the transmission feeds oil to the crank bearings in the Pro, unlike any other two-stroke you are probably familiar with. Jon

Probably just a through cleaning and checking of the carb and a mixture screw adjustment would fix the problem. Usually a tune-up (carb, filter, plug etc.) and adjustment will prevent this from happening in the future. Jon

The JTR's don't use a head gasket but have inner and outer o-rings to seal the head to the cylinder. You might want to check the jets just to be sure they are open, the pilot, for instance, is only about .35mm and is easily clogged or obstructed. Jon

I'd check: Cable routing. Make sure it's not crimped somewhere and that the cable is not being pulled out of the ferrule where it meets the carb top, especially when the bars are turned full lock. Throttle housing: Pull the throttle apart and check for broken pieces or binding in it's operation. Carb slide: Take the carb off and carefully inspect the slide for any scratches. Look inside the bore where the slide runs to be sure there is no dirt or scratches. You'll need to look very carefully as it does not take much to stick a slide. I've had a carb on a new 2010 come through from the Dellorto factory with some scratches in the upper bore of the body that caused it to stick wide open. It's a rare occurance but is a possibility. I doubt it's an air leak, those are usually consistant in symptoms and do not occur on a random basis. Jon

"I FELL OF IT AT THE FIRST TRIAL I DID WITH IT AND SCRATCHED THE TANK SO I TOOK THE TANK OFF AND MUDGUARD TO TAKE TO A LOCAL BODY SHOP TO PAINT RED AGAIN BUT NEVER GOT ROUND TO TAKEING THERE" He needs to take it back to the last "professional" that painted it while on the bike, judging from the overspray on the frame..... When I first saw it, I thought he had accidently posted the before photos. I'm still trying to figure out where all the money went...... Jon

Sometimes the multi-function switches are a weak spot in the electrics of off-road bikes as they are subject to a lot of moisture and grit, so that may be a contributing factor. Once in a while an electrical problem will be caused by a combination of several small problems and you need to trace all of them down. Since your bike starts/does not start, that a much bigger pain than if your bike would just plain not start at all. The not start at all syndrome is usually just one problem to trace down. The Kokusan V1 is a really good system and what I have on my 02 280 Pro and I don't remember hearing of a stator problem before, although there's always a first. It's not unusual for the flywheel key to shear on older bikes if the flywheel bolt has not been re-torqued. The huge number of heat cycles (in your case, almost 8 years worth) coupled with the heavy flywheel and shock loads a Trials bike engine encounters will loosen the hold the hub has on the crank stub over time. The "shear key" or Woodruff key does not hold the flywheel in alignment with the crank, it is only used to index the flywheel to the crank during assembly. If you could remove it after the bolt was torqued, the flywheel would still be held fast to the crank stub. When you get the flywheel off, you'll notice that the crank stub is tapered as is the flywheel hub and those tapers are ground at a slightly different angle from each other which results in them getting "stuck" when tightly pulled together, like with a bolt. That's why you need a flywheel "puller" to get them "unstuck" by pulling them apart. So, don't heat anything up when you put the flywheel back on, it's not only not necessary but counter-productive. The bolt will not need to be replaced but I like to put a little blue Loctite on the threads upon assembly. The NGK BPR5EIX is an Iridium plug and the best of all the plugs I've tested so far. Most shops don't stock a plug that "hot", a "5" as opposed to the normal "8" or "9" for most dirt bikes so I'm not surprized they had to order it. I think I've had the EIX in my Pro for over two years and I take it out and check it, no gap change so I put it back in and it's been perfect from 28 degrees at 12,000 ft altitude to 109 degrees at sea level, through rain, humidity even snow. I may put a new one in this year before I head up to Colorado but it will be out of mechanic's guilt, not necessity. Iridium plugs are designed to operate for 100,000 miles without replacement in a car. Jon

The rattling is normal if not too loud. The straight cut gears and clutch fingers are responsible from what I can figure but it normally stops when pressure is put on the clutch by the servo cylinder (when the lever is pulled in). Since It's an 03' model and has at least 7 years of use, if you replace the the two sets of caged needle bearings in the clutch hub (you can't judge wear visually) that will probably reduce the rattling. If you really want to hear clutch rattling, listen to a "dry" clutch in a roadrace bike like a TZ250, they sound like they are ready to fall off the bike... Jon

In that the bike runs well when it runs, I probably rule out the carb as faulty. Have you looked at the killswitch as a possibility? You might want to check that by disconnecting it to see if that aids starting. I'd also take the stator off and throughly clean/sand the stator contact points where it meets the case. An NGK BPR5EIX plug at .024" takes less voltage to fire. I assuming you have used fresh premix after draining the tank/carb. Old fuel makes for hard starting. I'm not sure if you have the Kokusan V1 or the Ducati Digital V1, but both are good systems and generally don't degrade in performance (both were used in 03'). I'm assuming you've taken the flywheel off to check, so a sheared Woodruff key is not the problem. Jon

Try checking the pilot jet first. A lot of the Pros come with a #35 pilot, which in some cases can lead to slight knocking when the throttle is quickly closed, especially in hotter weather. You might try a #38 and re-adjust the fuel screw to see if that fixes it. Jon

That's especially critical in the smaller two-strokes. The first 5-7" in the exhaust port (from the piston crown edge out) is probably the most important area in the whole exhaust system in terms of performance. The Trials exhaust system is unique among competition engines that usually run close to full throttle and maintain high temperatures in the port/tubing walls, which keeps carbon buildup to a minimum. The area where the cylinder port meets the header pipe has a high differential in surface temperature and it's common for there to be a thick buildup of carbon just inside the header pipe (right in the middle of the most critical area in the exhaust) so taking the pipe off and cleaning it out now and then is a good way to maintain performance. Jon

I'd make sure the filters up inside the tank are clean (on top of the petcock) and it flows sufficient fuel (sometimes the rubber disk in the valve deteriorates). As you replaced the float valve I'm assuming you checked the float level so that should be o.k. Check the fuel tank cap vent to be sure it allows air into the tank properly. Sometimes a new, properly gapped plug will help. Have you adjusted the carb screw for any changing weather conditions lately? The mixture screw needs to be checked now and then as the weather changes. Jon

I'd make sure the filters up inside the tank are clean (on top of the petcock) and it flows sufficient fuel (sometimes the rubber disk in the valve deteriorates). As you replaced the float valve I'm assuming you checked the float level so that should be o.k. Check the fuel tank cap vent to be sure it allows air into the tank properly. Sometimes a new, properly gapped plug will help. Have you adjusted the carb screw for any changing weather conditions lately? The mixture screw needs to be checked now and then as the weather changes. Jon

Boy, there's truth to that. There is a point of very rapidly diminishing returns when it come to spark lead. It should only be used very carefully as a tuning tool by the experienced and most of the time the stock setting is the most overall effecient setting. Incidently, the more effectively an engine uses it's fuel, the less spark lead it needs. In evaluating port/chamber modifications on a dyno run, the less static timing needed to produce good results was a good indication I was going in the right direction. In most 125's, proper factory recommended maintenance and tune-up proceedures will most likely yield better overall results in the power department than a degree or two of advance. Jon

Are you running a TK or Mikuni carb? Jon

Absolutely, John. I know your friends are probably a lot like mine and our photos would be on the front page of the local newspaper and the negatives would cost us dearly to keep from wider circulation. Course, in my case, I could wear a white suit and probably get a well-paying job as the new, live spokesman for Michelin tires..... Jon

In the case of the two-stroke engine, that's not been my experience. Advancing the static ignition timing from the factory setting tends to move the torque curve downwards, not upwards as it changes the IMEP (Indicated Mean Effective Pressure) and at lower RPMs provides higher gas pressure on the piston (and therefore the crank) after TDC. To test this, an engine at idle setting will gain RPM when the static timing is advanced. Jon

Yet another fine example of how willing one's friends are to promote your legend and rightful place in Trials history..... Jon

All torque reading are cold. You might back the nuts off one at a time and apply a little anti-seize to the stud to get a more accurate reading. Most of the GG pro cylinder nuts have a toothed surface to act as a lockwasher type affair so I'd use the upper range of the torque spec. and, of course, do them in thirds (1/3rd, 2/3rds, then full torque limit) and crisscross as you tighten the nuts to give a good, even surface pressure to the gasket. The bearings in the swingarm are a little tricky to work with so let us know when you do them and we can give you some pointers. Cheers. Jon

It can, but for issues related to combustion, it can reduce power at higher RPMs, much like raising compression too high. Jon

Thanks, Joe, those are good basic sources. You may be confusing the Mikuni with the Dellorto with the choke levers. Pressing down on the early Mikuni type lever turns the choke "on" and pulling the black plastic lever straight up on the Dellorto turns the "choke" on, which I'm sure is what you meant. Jon

Gordie, Cylinder nut- 18 to 20 ft lbs 25 to 27 Nm The swingarm bushings are not difficult, just time consuming. Don't forget the bearings up in the underside of the front of the swingarm, they are often overlooked. Jon

Did you see any nasty stuff on the magnet when you changed the oil? It might give an indication of a problem. It's not the gears that "crunch" (this is a "constant mesh" gearbox and the gears are always engaged) but a series of pins (sometimes called "dogs" for some reason) that slide into slotted collars and this is what transmits power to the gear sets. Shifting under load can sometimes round off the ends of the pins and that will bounce a couple of times before sliding into the slots and this sounds like gears crunching. Trials gearboxes are not designed to shift under load, but to stay in gear, so the pin/collar design is different from, say, a roadracer. A possibility. Jon