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Hi! Welcome to the Forum, I see you just joined up, you'll find a wealth of information and a lot of good people to help you when you need it. A small suggestion is to use lower case letters and non-text message shorthand, it makes it a little easier for old geezers like me to read (and it doesn't seem like you're shouting)..... Trials engines have a lot of flywheel weight and lots of low RPM torque and when properly set up, rarely stall, so your condition is normal. When you are stuck in a tough section, you'll probably come to appreciate it. In neutral, with the clutch lever out, a slight rattle is also normal and should disappear when the lever is pulled in. From what you describe, I doubt you have any thing to worry about. Again, welcome! Jon

"Zamboni?". Isn't that one of those Italian sandwich-like thingies they serve in Texas restaurants? I'd like to start a high-gloss monthly news stand magazine that covers only Trials, here in the U.S. and abroad. It would have modern and vintage coverage and special columns about the mechanics of Trials bikes. Trials Comp has done a wonderful job of covering Trials for the U.S. and this would help supplement their efforts (and I'd lure Shan into being Editor at an outrageous salary). I get pretty tired of picking up "dirt bike" magazines, of which we have many, on the news stand here in the U.S. and not find any mention of Trials. And I'd hire Copey as Chief Financial Officer so all my money would be safe........ Jon

Same with me. I havent used the SuperCool, but I've used Redline's WaterWetter (a surfactant that improves heat transfer between cylinder surface and coolant) for many years, including all the Pro level bikes and have never had any issues with corrosion. We did some unscientific testing under control conditions years ago on several competition bikes and found a temp drop in the 8-10 degree range, which is significant. Jon

Rod, Maybe I'll throw another opinion in here for you to consider. If, in fact, the circumstances of the seizure are as the dealer describes, it appears to have the characteristics of a classic "cold start" seizure, where the piston skirt expands at a greater rate than the cylinder bore (the symptoms will be seizure marks in the four left/right, front/rear parts of the lower piston skirt). Trials engines have extremely close tolerances in the piston skirt/cylinder junction (which is why they need to "normalize" tolerances before riding to avoid excess start-up wear) and I'm guessing that the actual damage would be restricted to the parts that the dealer replaced. The engine may have "revved to the moon", but probably dropped in RPM's before locking up when combustion pressure was unable to overcome the piston/cylinder friction, so it was more like putting the brakes on the crank (friction=heat=more friction=more heat cycle) than hitting it with a hammer. As I can't examine the engine, it's only a guess, but according to the dealer's story, the damage was probably localized. Jon

I don't remember seeing an 02" 125 at the time, but they do appear to be a little different by sight. I checked my 02' engine parts manual and there is only one crankcase assembly listed (125 to 280, so the engine mounts are the same) and although I don't have a chassis parts manual for the 02' Pro, the 03' chassis parts manual lists the frame (#BT280310000) for all the models, 125 on up. The curious thing is the chassis manual lists the same frame for 2002 and 2003 both, the "2003" is on the Spanish and the "2002" is the English translation. I've been told on very good authority that the 02' frame is different and handles a little quicker, but I don't know that for a fact. Guess I'll have to add this to the ever-increasing list of things I don't quite understand..... The oil capacity of the Pro 250-280-300 changing through the years is still somewhat of a mystery to me too. My 02' takes 350cc's to fill to the center of the sight glass. The 02' engine and clutchcover is Magnesium and the later ones (except for the Raga) are aluminum and the sealing system for the "top hat" servo cylinder post is 2 o-rings for the 02' and a seal and o-ring for most of the later. There are ribs cast on the inside of the clutch cover on the 03' on up and the 02' is smooth inside. I haven't taken the time to really compare the sidecovers to see if the 03's on up (compared to the 02') are wider for more volume or just that the sight glass has been re-located higher and they just run more oil in the case now. I like to run closer to 370+cc's than 350cc's now, 350 just doesnt look like enough to make me comfortable for some reason. I've never had any lubrication problems or oil out the vent hose, though. Jon

Got it. The PVC preload spacer is, I think, 1" "schedule 40" PVC pipe (it's the thick-walled stuff) and the way to get at the spacer is to pull the spacer and spring down and you'll see a (17mm, I believe) jamnut that locks the top cap on to the damper rod. Pull the spacer below the nut and you can, very lightly, put a set of locking pliers jaws on the rod to hold the spring/preload spacer down below the nut. Then, holding the jamnut with an open-end wrench, unscrew the top cap off carefully. Then you can pull the spring down and undo the pliers (careful, hold on to the spring while it extends) and the preload spacer will slide off. You might want to cut another spacer about 5mm longer to try if you want just a little more. Incidently, if the problem with your forks is bottoming out, a better way to address that is to raise the oil level in the forks (decrease the air pocket at the top of the tube), which will affect the last third of fork travel without making the center stroke harsh. I think the 03' takes 300cc's of 5 weight fork oil per leg and you may want to try about 315/320cc's. Jon

As an aside to the advice others have given about this bike, on the topic, I thought I'd throw another "trick" out that someone showed me many years ago. A two-stroke Trials engine will often auto-ignite (for various reasons, not only carbon buildup, and turning off the fuel can make the carb go full-lean before running out, further spiking the combustion chamber temp) with the throttle stuck open and at high RPM's the killswitch will not work. The best way is to take a glove off and with the wadded glove in the other gloved hand, stop up the exhaust at the end of the muffler and when the RPM's come down, use the killswitch to stop the engine. This technique has saved many a stuck piston. Hard to believe the dealer didn't check for the slide hitting bottom before startup. Heck, that's one of the two things we do when we sit on a new bike. Watch guys in a motorcycle showroom when they sit on a new bike, they (while imagining riding it) will work the levers and twist the throttle..... Jon

That's a tough question to answer, I think due to the various rim bead and rim channel designs, inside tire bead design and lock designs possible (some locks are smooth and some have ribs which grip the tire bead a little better and I run Nyloc nuts on mine, which may also take a little higher torque on the gauge for the same clamping force due to resistance). I've never run a torque wrench on mine, but would describe the tension as "snug" but not "tight", which, of course, makes little sense to anyone else. I do try to use the same length box wrench to be consistant. I suppose if I was trying to provide an objective, measureable means of checking rimlock tension, I might start with measuring the length of the rimlock bolt, installed snug in a bare rim, sticking out and that would be my gauge for the rimlock bottoming out and maybe give me an idea of how much pressure it may be exerting (how far the "wedge" is being pulled inside the tire bead) by how close it is to the stop point. Again, this seems to still be "seat-of-the-pants" engineering. I'm sure someone out there has figured a neat trick for checking tension on rimlocks. Anyone? Jon

Yea, there's a fine line between "tight" and "broken", as we all know.... Sometimes, replacing them with new ones really help. I've seen some pretty funky, corroded rimlocks (undoubtedly the original ones installed and the rider doesnt look closely at it) come out of vintage rims (and some newer bikes also) because the riders think they never "wear out", but corrosion and detached bonding (the bonded ones have a rubber outside and metal internal "T") make them much less effective. The bonded ones can split the rubber near the bolt stem, which greatly reduces the pressure the outer rubber exerts on the inside tire bead. Looking at it sideways , when tightened, it will look like a "Y" rather than a "T". Jon

I do the same thing but the reason may be different. If I carefully lock the nut against the cap and make sure the stem is straight out from the rim when installing the tube, in the future I will quickly be able to tell if the rim locks are not doing their job, as the stem will be canted to one side or another (rather than straight out). It only takes a second to check them before riding. Rim locks can be overtightened, which will pull the center down to the rim and the tire bead will raise up, taking the side pressure (and locking ability) off the rim. Jon

Mine is a 280, so I'm not sure if the frames are just slightly different in the smaller displacement models. The frame is standard but the complete airbox is a modified later model with 02' graphics. Jon

Go to: http://d-mis-web.ana.bris.ac.uk/personal/H...f/media/gasgas/ and click "forks" and that should tell you everything. Jon

I have an 02' 280. My favorite bike, still runs like a champ, even though the poor thing has been a trusty test mule for a lot of my crazy theories and modifications. The GasGasINFO videos are pretty neat, a few I haven't ever seen. The guy in the shop videos is Jim Snell, who is the parts importer for GasGas here in the U.S., and has probably forgot more about GasGas Trials bikes than I will ever be able to remember. He's helped me out a lot when I run into an unusual problem. Jon

Woody, I have the original Takumi video in my collection (it has a different sound track) and it's one of my favorites. I always enjoyed watching him at the World Rounds as he was extremely smooth and flowing in the sections. I was told that some of this video was taken at a kind of "Trials Park" in Japan that has a lot of old abandoned factory foundations to play on, but I don't know that as a fact. His balance and bike placement on the obstacles is amazing and he's always been one of my favorite WTC riders. Jon

I've used Slime in applications where punctures are the norm, like my lawn tractor and it works great. I've never had good luck with it on cuts, like a rim pinch, that are a little too long/large for the stuff to fill easily, but on thorn or nail holes it works well. If you use it in a tubeless tire, when it comes to changing the tire, it will seem like Extreme Fighting a huge donut filled with gorilla snot. Jon

I understand your confusion, everybody will tell you different info. From my experience, Trials suspension settings, rider to rider, will vary more than than any other forms of competition because of the speeds, loads, obstacles and riding styles. We rely more on body movement and leg power to supplement our suspension and riding style has a lot to do with how we want our suspension to perform. Some riders will ride "weight forward" or "weight rearward" which will have very different effect on the shock and forks, for example. In Trials, sag settings are kinda like carb fuel screw settings, they are just a place to start and need to be adjusted to suit the demands of the engine-in the case of a fuel screw, and a rider-in the case of suspension. Rear sag setting has a tremendous effect on how the bike steers at the front, which I think a lot of riders may be unaware of. For my riding style (observers may call it "falling off style") I've found that it is easier to compensate for "bad" sag settings at the forks and a rear shock that is not set properly is harder to adjust for. I'd recommend that you spend some time trying different settings (only change one at a time in order to not "blend" variables being evaluated) and see how you like the change, chances are that you'll end up with settings different from what you read. Jon

Dave, Generally, there is a jamnut under the top cap to hold it from coming off. If you pull the spring/preload tube down you'll see the nut and an openend wrench can be put just under the nut to hold the spring assembly back so you can unscrew the topcap off the damper rod. Then pull down on the spring and take the wrench out (very carefully holding the spring, as it can fly off) and the spring/preload assembly can come off. Try to put the top cap back on exactly as it came off (maybe by counting the exposed threads under the jamnut). The Zokes must have the oil capacity measured by level, not volume, as the cartridges usually do not fully drain (I'll try to upload the spec.'s). The 05's should have the steel tubes and the level is different from the later aluminum ones. I don't know how far you want to go with the preload, but 5mm at a time and check them out by riding is generally safe. Jon ps. TrialsPartsUSA has an excellent site for suspension spec.'s on the GasGas at: http://www.trialspartsusa.com/tech.html . I couldn't get the Marzocchi exploded view to download, but you should be able to do it later some time.

I'm guessing it's a 98' TX270 and the VIN number starts with "VTRGG27098-----------". Jon, "Hey! That's no porkchop, that's my leg!"

That might be the way to do it. That booger is down inside the shaft but you'll want to get the last piece out. Even though it seems welded in now, Murphy's Law dictates that it will loosen and drop into the clutch if left inside and the engine buttoned up. Jon

I like off-beat projects too and even if they are not practical, they can be a lot of fun. As long as you can accept the possibility that it may not work, you can always learn something from them. Porting can be modified to a certain degree. The cylinder base can be machined to lower the cylinder in the case, which will reduce the port/time area of all the ports and then you can modify the ports as necessary, say, to change the "blow down" time (the time that the exhaust and transfers are open at the same time), or stagger the transfer ports (open the rear boost port first, secondary transfer next and front primary ports last to increase low RPM scavenging) etc. Cutting the cylinder base will raise the piston crown a little above the cylinder, but you will need to machine the head anyway as the combustion chamber shape and squish band will need to be modified. MX heads tend to have a narrower squishband width and higher volume for higher RPM operation. Port angle and width are easily modified to increase velocity and direction if you so desire. There are a lot of other "tricks" (porting and otherwise) that can be done and you will need to decide what your time and resources are and how far you want to take your project. As mentioned before, it may not end up working as well as you wanted (but sometimes better) and as long as you have fun doing it, I can't see any reason why not. Jon

I also think so. As mentioned, the wires can be connected to effect constant operation, but you negate the purpose of the fan, which is to regulate the coolant temp under various conditions. The fan is not designed for constant operation, but intermittant use, and replacing the clip that holds the thermocouple in will probably cost about about 1/50th the price of a new fan, which usually is only available as a whole assembly that includes the motor, blades and housing. Jon

The "suggested" setting for the mixture (probably on the left of the screw in the center of the carb body,and a fuel adjustment screw) is only a start and is generally different for all bikes. If there was only one "correct" setting, it would not be adjustable. With the engine warm, quickly "blip" the throttle from idle and adjust the screw in/out until you get the best response. That setting is the "correct" setting for that particular engine, under those specific ambient weather conditions. So, your engine likes 3 turns out on the fuel screw and I wouldn't worry about it. I don't know for sure, but I think the shock centers are the same. You also may have an aftermarket spring, and with the increased "gap" between the coils, I'm assuming it's a "stronger" spring (a higher "rate" spring, in part, is dictated by the number of coils and coil diameter and one of the ways to make a spring "stronger"-higher rate- is to cut coils off it). I'm assuming you have tried backing off the preload collar? If not, try adjusting the collar about 3-5mm's at a time until it works for you. If that does not handle it, you may need a softer spring.

Matt, Pay close attention to the pilot jet to make sure it's clear. Suspension lubing is very important as it's easy to forget and when you feel a problem, it usually means you have to replace parts. Check wheel bearings for looseness and you might peel off the seal and pack a little waterproof in there to extend their life. Check spokes and don't forget the tripleclamp bearing as it is very often overlooked. Other than that, it's regular "check everything" stuff. Jon

Geez, Peter, you're right! I re-read his post and I had gone on a rant about the wrong thing.... That capscrew has a machined down head that makes the Allen hole very shallow, I'm guessing to clear the tophat servo cylinder at full extention. Your advice is spot on. Some riders leave the capscrew and shouldered machined washer completely out, upon re-assembly, as it makes pulling the clutch basket off easier later on. The servo cylinder will hold the basket on due to the internal spring pushing the tophat against the fingers. I like to re-install it just because I don't like any slop in the basket hub/splined shaft junction (loose parts make me nervous) but it can be left out without problem as I know several riders who do it. Jon

Jan, Your English is unbelieveably better than my Norwegian! I always appreciate your posts, they have been very helpful. Cheers. Jon