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There is a spacer with slots in it for the return spring tang, I'd look there first. Jon

It has an o-ring and a little carefully applied heat will help. Jon

.6mm (.024"). Jon

I was able to buy several copies at our NEOTT Octobertest Trial for myself and some Trials friends in Brazil and Europe (they will be delighted). I was able to spend some time with it tonight and it brought back some great memories, like the World Round we put on in 1982 at Donner Ski Ranch in Northern California. The photos are terrific! When I was reading about Norm Saylor (mgr. of Donner) and "The System" he developed, it mentioned the first Trials school at Donner Ski Ranch in 1974. I was at that week-long school and it was probably the most enjoyable week I've ever spent. Up on my Trials trophy shelf somewhere is a small, insignificant looking trophy for the most improved rider at that school (I had a long way to improve, so no place to go but up....) and it means more to me than all the rest because it has such great memories attached. Love the book. Jon

I think the full message box disease is contagious.... Paul, I think you message box is full too and have been trying to PM you. Jon

Most Pro riders find that 400-425cc's seems to work well. I would not wait until the fluid changes color as by that time you have lost all the advantages to keeping clean oil in the tranny. I also know of few, if any, riders (actually none) who are so adept at discerning transmission fluid color changes I would trust their ability to make maintenance decisions for any of my engines. I usually go 10-15 hours of fairly hard use on my Pro between fluid changes or sooner if the conditions are wet. My engine has 11 years of use and I've not had clutch, crank or transmission problems and I would suspect keeping clean oil in the engine has helped. I guess what I'm saying is that I just don't see the logic of using a condition of something to be avoided (junk in your oil) as an indicator for action to avoid that condition. Jon

Martin, Mike brought the books up to the Octobertest Trials site this afternoon and I'm going to get some of them for friends. A lot of interest in the book here, I'd forgotten how good it was! We're using them as part of our awards this weekend and will use them for part of the end-of-the-year awards. An excellent book to have and they make good awards for the clubs. I was really happy they became available as I lost my copy in the move out here from California. Thanks Martin! Jon

Best place to start. Jon

My 02' 280 is some what "special" in design but actually just a cuddly pussycat. It will do anything you ask, just don't ask too loudly....... Jon

You can borrow the Pro, the trick TY is too valuable to risk a "shunt"..... Seriously, you can use my Pro at the Octobertest, I'll be working the sections and can use one of the TY's to get around. Always glad to help out a friend, even if he IS a Texan..... Jon

For a "standard" size bike, use the WM3, which is used on just about all the bikes (125, 250, 280, 300 etc.) available now. The narrower rim will distort the tread footprint and cause traction and handling problems. A narrower rim would require a "smaller" tire to fit with the inherent lowering of performance standards. Why do you ask? Jon

We love ya Mark. If we don't like you, we ignore you....

Those are "targeted" ads, Copey, I didn't get one. Has your "friend" been complaining on Facebook or somewhere.....?..... Jon

I feel your pain, having experienced the same thing........ Jon

Excellent! The competition is tough at that level. Jon

Sad to hear that. Bob was a well-known racer and tuner in the 60's and 70's in the San Luis Obisbo area (Central California coast). I used to love to go down to his shop and bench race with him. He was always there to help out any rider that needed it. A larger than life personality and he added so much to the Trials sport. Jon

tazz, even on non-floating disks you will get a small amount of movement with the brake on as the pads move slightly forward/backward in the caliper housing, so under any circumstances there will be a little movement. Jon

True! Use your fingernail to slide over the shaft, it is amazingly sensitive and if you feel any groove it would be wise to replace the shaft. I also use the fingernail technique to check for imperfections on fork tubes. I learned suspension theory in one of the best shops in the U.S. and we found the fingenail worked better than any other tool we had for uncovering pits. scratches etc. The newer WP shafts have a better heat treatment and last longer. I think that certain anti-freeze products have a higher silicate content and this may contribute to slightly faster shaft wear. Jon ps. Mitch, I'm going to try to make the Peru event!

Like htrdoug and Steve say, try them all. Each bike has a little bit different personality and one will just "feel right". They are all good bikes and will work well for you, but the ergonomics differ enough that choosing one will be a personal decision in the end. Jon

At 16 stone (224 lbs) you may want to consider a heavier spring. If you are a new rider and havent developed the "unweighting technique" the stock spring will be a problem. I'm a little over 14 stone and don't have a problem with the stock spring but I've learned to not overwork the suspension and absorb the bumpy stuff with my legs. If you are coming over to a Trials bike from the bigger off-road bikes, the suspension will seem too soft at first. Jon

Mitch, A lot of the bearings are rated "high speed" and for that use do not require much grease (it would just pop off the shields) but at the speeds we use them you can just about pack them solid. Jon

Mitch, The crank bearings have a short dedicated feed hole machined into the bearing boss where oil thrown up by the gears makes it's way into the bearing. Jon

Actually, that should be .1mm per inch of cylinder bore, not .001". The dial bore indicator will give you a measurement of cylinder wall taper, usually the highest wear area is about 3-5mm below where the upper ring stops and relates to peak cylinder pressure on the power stroke. I've used clay before for squish clearance but find the solder method more accurate. The clay need to be a certain type to get good readings, as too soft or pliable will often distort and a release agent should be used on the head or the clay will thin when pulled between the head and deck, giving a bad measurement. You must also be absolutely sure to lift the head straight up as any side movement will distort the clay layer. I like clay for combustion chamber profiles, but as I mentioned, you have to be very careful, which may be a problem for a first-timer. Jon

Good advice. Use a piece of curved soft solder through the plug hole to measure and look for a squish clearance of at least 1mm (.039 in) and you should be o.k. As to the o-rings, grease the complete o-ring (and all o-rings) before installing and that will keep them from tearing or being cut. This allows the o-ring to move slightly and "settle" in the groove. A good example is the very thin o-ring on the Pro waterpump body, which will often be shaved in half if not greased (and the body pushed in square to the bore). Jon

Heat is not usually a considertion as to a floating disk. It allows the disk to self-center in between the pads. Some systems "float" the caliper (common on dirt bikes in general) and use a rigid disk. There are stress forces that misalign the forks slightly and if the system were rigid, there would be a gap between pad surfaces and the disk and you would have to take up the slack, resulting in a spongy, long travel lever. The back brake, being a more rigid system and smaller disk, usually has a non-floating disk. Jon