jse

huski seems to have the experience necessary and the seal changing is pretty much the same as other forks but setting oil level may be new to a lot of riders and I think that's where the rumor that the Zokes are difficult comes from. The Marzocchi's compression cartridge does not drain easily, therefore you can't use oil volume without the danger of overfilling the leg and running into hydraulic lock. Copey, I think you and I should get together and make a video on fork servicing. I bet we would be the Nitro Circus of technical how-to, or maybe how-not-to in our case. Jon

In the last photo I just had the plate in to keep the rod from dropping down but here it is above the spacer:

They are fairly straight forward except that you will need to set the oil level and not use volume. You will need to remove the spring to set oil level (180mm for steel tube and 160mm for aluminum tube Marzocchi's). If you make a simple tool like this aluminum plate it will make messing with the spring a lot easier. Pull the spacer down and insert the plate, then you can remove/install the top cap easier. They also take a pin spanner to remove the top cap on most of the Zokes and use a little heat to break the o-ring bond. The top caps only are tightened to finger tight. (the tool on the top of the damper rod is used to bleed the cartridge easily) Jon

Toe wiggling counts as half points....... I had always judged it as a one point loss and was surprized when the subject was brought up as I thought they had changed it somehow and I just didn't know about the change. Ron is going to contact the NATC guys to get final clarification. If they are now counting rotation as an additional point, this is a new intrepretation I had not heard about. And, the degrees of rotation for the additional point will be an issue, unfortunately. Jon

Some of the clubmembers are having a discussion regarding interpretation of the written NATC rule for foot rotation. The choices are: (1) one point for the foot plant and another point for rotating the foot= 2 points for dab and rotation. (2) One point for for dab and no added point for rotation= 1 point for dab and rotation. We all agree that a dab and drag is 3 points. Any opinions? Jon

I've also found the misconception interesting. It seems the perception is slowly changing with such Trials names as David Knight, Taddy, Geoff Aaron, Dougie, Wayne Braybrook etc. creeping into the awareness of U.S. riders. The past also had other Trials riders such as Roger Decoster and Kevin Schwantz go on to other forms of motorcycle history. I have heard more people not involved with the sport say they have seen Trials on TV here in the U.S., so there seems to be a change in exposure. Jon

I've used WD40 on the plastics on my bike, shines them up and keeps muck from sticking. I usually am very careful to spray a rag and wipe on to keep overspray off certain components, like when near the area of naughty bits like brake calipers and disks. Jon

I think there is also another factor to consider when trying to bring new riders into the sport. Trials is unique both in skills required and rules, when compared to all the other forms of motorcycle competition I've participated in. Most motorcycle sport is: start when everybody else does, go as fast as you can and not fall off, period. Our rules (which we often change each year-stop, no-stop, o.k. to back up, not o.k. to back up, at what degree of incline is a wall considered "ground" when a handlebar touches it etc.) and "proceedures" (unwritten, such as not parking one's bike in the trail, not blocking the start of a section or loudly swearing when one makes a mistake-you can do it with a full-face helmet in the first turn with 29 other riders at full-bore but it is highly frowned upon when families are spectating at the section) are fairly extensive and can be intimidating at first. Even experienced Trials participants often seem to spend more than a fair amount of their time discussing rules interpretation, a process I rarely experienced in the other forms of sport I was involved in. When setting section difficulty for beginning classes, I think we need to not only consider the difficulty of section riding but the difficulty of participation, overall, for new riders, and take that into consideration when we set "obstacles" in their path. Jon

The rod "spec.'s" should be easy as the parts needed will be the rod (outer race), the crank pin ("inner" race) and the bearing and any good crank guy will know how to set the side clearance when pressing the crank. You probably want to replace the seals and crank bearings, which is normal proceedure in an engine that old and the piston pin bearing also. Check the cylinder lining and if it's in good shape find the letter marking (A,B,C etc.) and you should be able to put the next larger piston in with little problem as the normal wear will be about the difference between the piston sizes. So if the have an "A" cylinder, you can put a "B" piston in. Piston ring end gap is .1mm per inch of bore and piston skirt clearance should be in the neighborhood of .0015 to .002". Use a caliper and measure the thickness of the old cylinder base gasket(s), which will give you a place to start for setting the squish clearance. Adding a few thousands for gasket compression, you'll have an idea of what gasket(s) to use to get the appropriate thickness. Using soft solder inside the assembled cylinder, measure the squish clearance and you'll want to have it at about 1mm or .039". If you run into trouble, if you want, you can PM or e-mail me or contact me off the GasGas USA and UK websites under "tech" or "support", but if you are in the UK, you can't beat Kevin Hipwell's advice, he knows more than I do. You can also post to this forum and tap in to a huge amount of experience from all over the World. Jon

I'm not aware of any service manual, hard copy or web based, that would have the spec.'s you are looking for. Rod big ends are usually set-size as you'll be replacing the rod/bearing/journal as a unit. As for the piston, there should be a letter stamped on the crown as to it's size and the cylinder will usually have a corresponding letter stamped on the back or on the gasket surface. Jon

Will do.

Generally, you need three things for a two-stroke to fire off and at least run for a period of time: 1- Fuel/air mix in a ratio close to 15/1 2- compression 3- spark at a reasonably accurate time in the crank cycle It sounds like the first two are covered, so I'd look for an electrical problem such as poor plug cap, bad grounding of system, wiring shorting out (especially down around the stator area where you can't see it) etc. You can check for spark but this is not always a positive indicator of performance as a plug will emit a spark when the plug is taken out but not under compression when installed. Jon

What might be of use is a spray called "fogging oil", which is used to spray into personal watercraft engines when they are stored for Winter. You should be able to pick it up at any PW dealership (a lot of them also sell bikes). Jon

The photos of the area look pretty neat for Trials. I told Danny Aguirre I'd be down to help with tech inspection. He helped me with Tech the last two Nationals we held and we make a good comedy team. Oh, I don't think we'll have an Elk head at this years tech inspection, but I'm sure Danny and I can find something...... Jon

Remember?, I used to BE one of them..... Jon

Remember Copey, you have to eat what you kill.... on the spot. Jon

If you plan to keep the bike, I'd probably have your cylinder re-plated. You'll need a new piston to send with your cylinder, in most cases, and the piston skirt clearance spec.'s (undoubtedly available in the excellent Honda service manual) so they can diamond-hone to the final size. If it's a company that does Trials cylinders they should know what to do, but some re-platers do not believe the clearances should be as tight as they are from the factory and will tend to hone to looser than should be. Tell then exactly what you need. Jon

I'm pretty sure the 88' has the "damper rod" forks, not cartridge type, and they take a heavier weight oil in the nature of 15-20 weight. Jon

Try: http://www.trialspartsusa.com/tech.html . There is a three part Pro engine repair video that should cover it. Jon

If you pull the spring end back (in tension) you can put a ziptye around the arm and spring end. Install the assembly , tighten up and then cut the ziptye to release the end up against the swingarm. You can hold the end with a pair of pliers to ease it back up if you want. Jon

Here's what to look for in a four-stroke cylinder with excessive piston wear. The two-strokes have the same problem with excessive piston wear damage, but they tend to experience piston skirt collapse, usually on the rear part of the skirt. Jon

I'd run in the range of 50-60:1, full-synthetic premix oil. The smaller engines run a little hotter and can develop localized hot spots. Jon

Wayne, I checked on: http://www.trialspartsusa.com/tech.html and they have some good written info but no videos (Jim Snell does the excellent how-to videos, he's much more handsome than me...) on how to split the 50. My personal experience with the 50/70 is very limited as they are rare in the my area. As I remember, the engine takes normal tools to service other than the thin-wall socket for the clutch, which can be fabricated. I'm not aware of any unique problems with disassembling or assembling the 50/70 series engine. I always have some small, strong magnets stuck to the toolbox lid so I can drag one of them through drained oil if I need to check for unusual transmission particles. As for the magnet drainplug, the magnet sticks out a little so be sure there is clearance inside the case when the plug is tightened. Jon

When you have the cylinder off, look very carefully at the front, top of the bore, about 5mm below the top. With the "slipper" type pistons, a worn skirt will cause piston rock and often wear the plating through on the "thrust side" of the cylinder. A very slight amount of piston pin "offset" helps to keep this from happening, but a well worn piston can damage that area. Jon