jse

Did you put absolutely fresh premix (no old premix whatsoever) in a flushed-out tank? Some mineral-based premix oils will cause carbon buildup in the exhaust headpipe, you might want to check. Exhaust restriction will cause overheating. Jon

I think you'll like the flywheel weight, especially in no-stop conditions. By "storing" energy in the flywheel and using it, rather than more throttle, in iffy traction situations, you'll lose a lot fewer points as the power to the rear wheel is much more smooth. Jon

He said "plunger size", which makes me guess he means bore diameter but there may be other measurements I'm unaware of. The 20/22mm measurement may be circlip stop to effective piston seal area rather than plunger length. A longer stop-to-seal measurement may not allow the seal to retract back far enough to clear the orifice connecting the reservoir to the bore, effectively resulting in a "closed system" unable to "self adjust" (like what happens when the lever adjustment is screwed in too far). I'm guessing he needs the #BT27722208 kit (9.5mm bore, DOT-4) that fits the 97'-04' clutch/brake MCs. Jon

Generally, 9.5mm. The 20/22mm is probably for a larger vehicle. Jon

Head gasket on 350 is also copper. Should be annealed before re-use, heat to cherry red and let cool on it's own. It will then conform to irregularities upon installation. Jon

Looks good! As with any used bike, assume that nothing has ever been serviced and take the time to go through every part (bearings especially) for lube and adjustment. It will pay off in more riding time and less fixing time. Don't be afraid to ask questions, as you can see by this forum, we are a helpful group in general and here you have access to experience from, literally, all over the World. Cheers. Jon

97' JTX is a good bike to start with. Strong and handles well. As with most Trials bikes, with care it will be reliable. Here in the U.S., it's almost impossible to ever find a Trials bike in a cycle wrecking yard. Welcome to the gang. Jon

Mitch, 3, 4 and 5.1 are essentially the same (5.1 is a lighter viscosity, common to European high-speed ABS systems) but they are very different from DOT-5, which is a Silicone based fluid. The DOT-5 is common to military vehicle brake systems due to it being much less hygroscopic (an ability to attract and retain atmospheric moisture, yes, spelled with a "g") so storage is less of a problem and it lacks the strong solvent properties of the 3/4/5.1 type. It does, however, make the brakes feel "spongy" due to it's minimal compressability, so you will probably never see it used in racing brake systems. You can use mineral oil in a clutch system but should never use it in brake systems due to it's low boiling temp. Mineral oil, DOT-3/4/5.1 and DOT-5 are not compatable so they should not be mixed unless you want gundge in the system or desire to replace the mineral oil seals/o-rings that have been damaged by the solvent properties of DOT-3/4/5.1. Jon An exerpt from one of my answers to a question a rider sent me: It’s hard to imagine a subject duller than brake fluid, but it’s something we have contact with just about every day, directly or indirectly. Most of the time we could care less about it, but in Trials, it’s a very important material and just about all Trials bikes have three separate systems that employ brake fluid to transfer motion that make us both go and stop. Hopefully, the result of that going and stopping is dependent on years of hard earned Trials experience and razor-sharp athletic prowess, rather than an immovable object such as a tree, which is usually what happens in my case. I like to change brake fluid about every six months when possible. It has an effect on how the controls “feel” and fresh fluid will prevent corrosion caused by water buildup in the calipers and cylinders. The polyglycol based brake fluid (DOT 3, 4 and 5.1, as opposed to the Silicone based fluid which is DOT 5) is what is called a “humectant” in Chemistry, meaning that it promotes the acquisition and retention of water. Glycol is an alcohol derivative and alcohol is the main component of gasoline additives that are designed to drive water from the fuel systems of automobiles. Polyglycol and Silicone are used in brake systems rather than another fluid, such as water, because it stays relatively consistent in viscosity from cold to hot, has a very high boiling point and provides good lubricating qualities for the various parts. Water will get into your brake and clutch systems in a variety of ways, usually from a brake fluid container that has been opened for a while, or past the venting diaphragm under the master cylinder cap. It will collect in the lowest part of the system, usually the caliper assembly, where it will corrode the alloy components and rapidly degrade braking ability. Flushing it out when you change fluid is the only way to remove it. I like to slightly overfill the master cylinder reservoir when replacing the cap so as to minimize the amount of air (and water vapor) under the separation bladder the cap rests on. The water absorption problem is so important that some manufacturers of high level racing fluids recommend that the brake systems of racecars be bled before each racing event, particularly in wet or humid conditions. Another of the big differences between the glycol-based DOT-3, DOT-4 and DOT-5.1 fluids is the wet and dry boiling point. The “wet” boiling point is tested with a 3% water addition to volume. DOT-5.1 brake fluid was designed to be used in European automotive high-speed ABS systems. It has the lowest viscosity of the glycol-based fluids. DOT-5 is a different kind of animal altogether, and has a Silicone (Silicum-based Polymer) rather than a glycol (Polyalkylene Glycol Ether) base. One of the nice things about it is that it doesn’t eat the paint off your bike like the glycol-based stuff does. I like to use it in my clutch because it tends to smooth out the action and I like the “feel”. If you wanted a “quicker” action to the clutch, you might want to use the DOT 5.1 type due to its lower viscosity. The Silicone-based fluid doesn’t “absorb” water like the glycol-based types. The water will separate out as globules and can still cause problems if not flushed out on a regular basis. Although it would seem that all the fluids should be able to be mixed, especially the DOT 5 ratings, such is not the case. DOT 3, 4 and 5.1 (amber or clear in color) can be mixed, but DOT 5 should never be added to anything other than itself. It is a chemically different compound, being Silicone based, and will give a cloudy mixture that looks like Jell-O when added to the glycol based fluids. Silicone DOT 5 is a purple color (by DOT rules) so it won’t be confused with the other types. Some racing brake fluid can only be mixed with itself and won’t mix with any other brand, such as AP600 (designed for the carbon-carbon brake systems of F-1 cars). If you feel rich, you can get some Castrol SRF brake fluid, but it will set you back over $80 a liter, a little less than a quart. Buy fluid in small containers that will be used quicker. Never reuse fluid that has been drained and keep the caps tight on the containers to prevent moisture contamination. Remember, it’s a LOT cheaper to flush brake fluid a couple times a year than buy new components.

I like to fill the top hat with fluid before installing on the post. This way you avoid the air pocket at the back of the servo cylinder problem. Be sure to fill the reservoir only about 1/2 way full, it does not vent the same way as the reservoirs on the bars. Clean fluid is a good lube, as Sting says. You can also use a very light coating of Silicone grease (VERY light, you should only see gloss, not chunks). If you wanted a smoother clutch, you could change to DOT-5 (Silicone), which, unlike DOT-3/4/5.1, is slightly compressable. DOT-5 is compatable with all the seals. Jon

Coxy, Technically, there are no "standard" settings as each shock should be adjusted to the individual rider's weight, riding style and preference (this is why they are adjustable, like a carb's fuel/air screw setting). A professional suspension shop will have recorded all the critical settings and measurements before dis-assembly and will have reset the shock back to those specific settings before returning it back to the owner. Jon

The stock TY350's throttle response is akin to a sheep with asthma........ Jon

Glenn, The extended spigot is so that the end of the carb spigot mates up against the special one-piece manifold/reed block. This way there is no "gap" inside the tubing between the end of the carb spigot and the beginning of the manifold spigot, which would form an "expansion chamber" of sorts inside the tubing. You want the cross section area of the intake from the needle jet to where the fuel/air column starts to expand into the area under the reeds to remain as uniform as possible. Any area variation will tend to degrade the air column "signal" at the needle jet orifice. The reason that flat slides work well and are so responsive is that the air column is not "split" around either side of the cylinderical slide (right at the area of the needle jet where it's most needed) but is concentrated over the needle jet, thereby vastly improving the pressure/vacuum "signal". Jon

Jontow, That is fuel-proof reinforced tubing. What you can't see (except for the "ring") is the machined spigot extention I installed that fits down inside the tubing. Jon

I also run the Mikuni (with modifications) on my 85' TY350: Good little carb, works very well. Jon

A little careful heat from a propane torch or a heat gun will break the bond and the seals will come out a lot easier. I always use a torch with no problem but some are afraid of burning something, never have.

Here's a simple tool to help with the top cap removal/re-installation. Each leg takes 300cc's of 5-weight fork oil. Jon ps. Almost forgot. That top cap only is tightened to barely snug. It's held tight by the upper tripleclamp and the oil seal is by the o-ring, not how tight you torque it down.

ANY up/down movement of con-rod is cause to replace. With this extensive engine damage, I'd guess dirt sucked past the air filter or foam filter not oiled. Jon

Dani, I would carefully inspect the inner and outer surfaces that contact the bearing needles (they are actually the inner and outer "races" of the bearing). They may be damaged. If so, those parts also need to be replaced. Jon

Gotcha. The new pack will undoubtedly have the two 2.0mm steel plates. There are two fiber plates the same thickness and the third fiber is the one used to set the pack width at the factory. That thicker fiber plate always goes in the clutch basket first. It's usually a drop-in affair but you may want to measure and record the finger height just to have as a baseline. I like to soak the fibers for a short time, mostly out of old habit. Save the old clutch, it can come in handy for parts sometime. Jon

I don't remember seeing what your plates measured out as to start with. If it's an earlier clutch pack, you could have a number of thickness' plates. If it's been replaced with a newer pack, both plates will measure 2.0, and you will then end up with an 8.8mm pack, which will not work. What is the thickness of the installed plates in your old clutch? Jon

Chuck, You need to ride the U.K.'s Scott Trial. Time/Observation Trial and a free for all in the sections. Very tough, started in 1914. Jon

Gary, The whole bike is a work of art. I know from experience how much effort went into it. Well done. Jon

I have a very creative imagination, which in most cases has served me very well throughout my years. In this case, it has become a curse.......... Jon

Check with Jim Snell. They may have some reasonably priced aftermarket shocks. The problem you have is not unusual as the adjustment screws are fairly delicate on shocks (all shocks) and riders will force them when bottomed out. Kinda like the top caps on forks where riders think tighter is better when they should only be just snug. Jon

Oh cool! I'm driving out to the Ute Cup next week and will see Chuck there. It will be like RMTA's version of the half-time show at the Super Bowl except I sure don't want to see any wardrobe malfunctions.......... Jon