jse

Be sure to try a torque wrench on the axle just to "feel" how tight it should go in the future. A lot of riders (myself included at times) tend to think that more is better when tightening fasteners and I'm sure I'm not the only one who has snapped off a bolt head in the past.... Jon

I would think that when you see the dark color it's too late (and how dark is "dark"). Low level moisture contamination and the breaking down of lubrication additives will probably not show in color and "color" a lot more subjective in nature than hours of operation. You will also want to change the oil after a wet Trial, regardless of color. Certainly judging color is one way to schedule maintenance but I think that hours of operation may be a little better for the engine over time. You want to prevent the gear teeth and roller/needle bearings from having to run in contaminated oil in the first place. Jon

I usually remove both seals carefully with a dental pick and put a mixture of 70% waterproof grease and 30% anti-seize in. The anti-seize helps prevent galling in thin lubrication conditions. I use BelRay motorcycle grease but there are others that work well. Not all grease resists water well so make sure it's water tolerant. I probably get 12X the life from my bearings that you were getting. Now and then, when I have the wheels off, I'll remove the outer seal to see if a little more grease is needed. Most of the bearings we use are made for higher RPM's/temps/less shock loads and less moisture than they see being used in a wheel and you'll be surprized at how little grease is in some bearings to start with.

They seem a little short lived. Be sure to re-pack the new bearings with grease and tighten the rear axle to 30-37 Ft lbs (40-50 Nm). You may want to check the axle with a torque wrench to avoid the unecessary side load on the bearing caused by over-tightening. Jon

Blot the fluid out of the reservoir and you'll see the bleed holes (there are sometimes two about 2mm apart, a very small hole in front and a larger one next to it). Try taking the lever off and pull back the rubber boot to make sure the piston shaft is retracting fully back to the circlip (there is a collar that rests against the circlip). Some of the earlier M/C's had a problem with the spring in front of the seal sacking or breaking, which meant the seal would not retract back enough to uncover the bleed hole. The 370 was one of my previous bikes, fun to ride. Jon

I'm assuming that the M/C piston is returning completely back to the stop at the circlip, uncovering the bleed hole to the reservoir. If you have the lever attached and the adjustment screw in too much that bleed hole will be closed off and fluid won't make it to the reservoir. I'd try re-installing the old components and see if fluid comes up into the reservoir. It might be that the new kit is for a different M/C and the piston shaft is too long, which will not allow the seal to come back far enough to uncover the bleed hole and open the system. Jon

Bolt centers are 60mm+- on 02' with GG forks. Jon

I made two heavy-duty shop spindle tools but also this little short one I carry in the toolbox in the bike trailer. You can screw it in the end of the spindle and tap the spindle out. It also works as a leverage tool to draw the spindle end into the frame hole upon re-assembly. Jon

Al, I'd try some penetrating oil to see if that helps. You need to be fairly gentle as that spindle is aluminum. Sometimes loosening the engine mounting bolts and/or sump guard bolts will "relax" the hold the engine case has on the spindle (the engine is a "stressed member" part of the frame). It will also make it easier to line up the spindle end when you re-install it. There is a special tool that threads into the spindle and makes it a snap to align the spindle end into the frame hole but you probably can do it without the tool. I made a couple of these tools and they really help if you are doing this job now and then. Jon

Chris, If you're not familiar with forks, I'd have someone check them before stripping them down, like you are going to do. It may be that the noise is not from the fork at all (may be disc or brake pad related and normal). I doubt you can feel how the damping is working unless you have some experience. Just pushing up and down the forks is usually too slow a movement for the damping mechanism to have an effect that is noticed by the average rider. Jon

One of my favorites too! I once had a Chevy Astro AWD van and didn't like the flimsy plastic center hubs on the aluminum wheels, so I machined the crowns off of four RM250 Suzuki pistons to use as polished wheel centers, does that count? Jon

Excellent. Jon

Chris, For the first step, I think you'll need to pull the forks off and dis-assemble them to see what the problem could be. Jon

I'll second that! Jon

There's some info at: http://www.trialspartsusa.com/tech.html on the Marzocchi's. You might try 2.5 weight fork oil but I'd be a little leary of removing a shim from the rebound stack. To do it safely you might need some special holding blocks for the cartridge body (they grip the tube without crushing it) some replacement shims as it's always better to replace a shim with a different thickness/diameter than leave it out (and you need to know which shim to replace as it's not an intuitive process). There are other ways such as polishing the inner tube and the outer part of the springs etc. but that may be more than you want to do. If rebound is too fast, you'll have to deal with increased deflection and "skating" with the front tire so there is a point of diminishing returns. Jon

That was my first thought too, but the "sudden-onset" symptom pointed to the most recent "activity" as possible cause, which was the replacement of the head. Of course, it always is a possibility that several small causes will exhibit as one big symptom so it could be both an air leak and cable malfunction or even the rubber tip of the choke plunger coming loose and holding the enrichening circuit open to a slight amount. Jon

I'm suspect of the throttle cable also. I always think about what parts are moved/changed when repairing something (and another problem comes up) and in this case, it's the fuel tank. I'd closely inspect the cable routing and see if it got kinked somewhere. Make sure that there is a little slack and maybe take the cable off to check for a frayed end. This usually happens at the throttle end and it only takes one wire to come off the strand to catch inside the housing or inside a ferrule or fitting. Jon

Dustin, I would think that ATF would work. It's about 7.5 weight, which is right in the ballpark for recommended viscosity rating for the Zokes. It also has good lubricity and anti-foaming additives like regular fork oil. Give it a try and see if you like it. Be aware that the Marzocchi's need to be set with oil level and not oil volume. Jon

Thanks, Martin! I'm looking forward to seeing some of these guys at the Texas National next month! It's going to be an interesting season. Jon

Jon, That's the way to do it. I sometimes use water or WD40 as it cuts a little faster. Use a light pressure, "figure 8" motion as it helps to avoid too much pressure on one side, resulting in a "wedge shaped" piece. Jon

One of the things we did to those to make them work better was to take the caliper apart and use a surface plate (or thick piece of glass) and some 220 grit sandpaper to get the sealing surfaces straight, otherwise they were prone to flex. Jon

Jon, Does the lever hit a hard spot before it meets the grip? Jon

I think there's a spring in the lever assembly (if it's a PHBL) that you'll see when you pull it out and it may have broken/sacked. That spring locks down the lever in the up position as well as putting pressure on the piston to seal off the passageway for the enrichening circuit. Be sure to check the master cylinder, you might need a rebuild kit as the bore may be a little tapered with age/use, so the piston seal will not last as long as a new M/C seal would. Jon

Jon, You'll find a parts manual and other good downloadable info for your bike at Jim Snell's website: http://www.trialspartsusa.com/tech.html . General consensus is that 80:1 of a full-synthetic premix oil works well. 650-700cc's of Dexron ATF, changed often, is a good place to start as far as tranny oil is concerned. Standard drain plug (6mm Allen?) on the bottom and the same type plug to fill at the top, usually by the kickstart shaft area. Cut 5mm off your old Allen wrench as the plugs are aluminum and easily stripped out. Post any questions you have, there are still a lot of the old bikes out there. Incidently, your engine is designed to run on minumum 95 octane as it is fairly high compression (as you've found out from trying to kick it over). Jon