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R100GS Spline Lube

Spline lube  for R100GS

Dan Dunphy

Becasue of a transmission failure I dissassembled my GS at about 45K miles. Here’s what I learned. Having neither the special tools or the knowhow to rebuild the transmission, I took it to Paul Swenson of Colorado Springs. The failure was the front
output shaft bearing. On dissasembly of the bike I aslo determined the rear u-joint was notchy in one plane, so off to Neff (Eurotech’s rebuilder) it went. At Paul’s suggestion I removed the clutch disk and cleaned everything thouroughly, especially the spline which was quite dry, even though it was lubed the previous year.

Here are some tips.

1. Make 6 headless studs 40-50 cm long in order to put the clutch back together. Without them it’s a three handed job, at best, even with the special disk   alignment tool. 6mm X1.25 pitch.

2. Make 2 headless studs 8mmX1.5pitch, again at least 40-50cm long in order to slide the trannie back without hanging it on the spline. Bolts can be used here per previous articles.

Much of the dissasembly and reassembly procedure have been covered previoulsy by Bob Paskar and Ron Miller , so I will not comment except where I deviated from thier procedures. These notes apply to the late model with the large hole pressure plate. This is not the type shown in my Haynes and Clymer manuals. The proper grease is no longer Starburgs, but BMW #10.

You should remove the clutch assembly and clean the spline thoroughly. Lube sparingly, the contact points where the spring rides in the flywheel (the entire outer circumference), the points where the springs contacts the front of the pressure plate, the clutch plate spline, center bushing in the flywheel, as well as the center bushing in the spring. I also lubed the tip of each spring finger.

Clean and sparingly lube the transmission input splines, a toothbrush works well here, making sure to lightly coat all surfaces of each spline.

Clean and lube the throwout bearing. Using the tube of BMW #10, I squeezed grease into the throwout bearing, then put the end of the throwout rod in to pack it in, and repeat until clean grease comes out around the edges. Paul tells me  this is a $90 part, don’t neglect it. It’s very easy to get at, even between spline lubes.

Grease the bearing in the pivot point of the clutch lever. The sleeve will come out, but be careful not to drop the needles. I pushed the sleeve out halfway, pack one side, then push it thorough to the other side and repeat. If it won’t turn, replace it. This is the time to renew the speedo cable boot if needed, as water gets in here. Some silicon gease around the cable where the boot seals will help here. If you removed it, you must grease, lightly, and return the throwout rod to the transmission BEFORE you put the swing arm in. Ask me how I know.

Also, Put the wires back on the neutral light switch before you slide the transmission home. Rear drive and driveshaft. Like a number of others, I had to file the driveshaft housing to get the rebuilt shaft in. I bought a section of 1 inch 60 grit sanding belt, and used it inside the housing like a polishing rag. This will get junk in the bearings if you are not careful. Some instructions said not to repack the bearings, as the shaft breathes through them, my studs had holes all the way through, so I repacked the bearings.

You cannot grease these bearings, like the ones on a monolever because there is no backing plate behind the bearing. I found an EASY way to reassemble the rear spline and rear drive, I did it on the bench, but it could be done on the bike if you understand the concept..  Put the rear drive in a 6 quart oil box, to keep it from rolling around. Push the driveshaft as far into the housing as possible so the rear yoke is accessable. Align the driveshaft housing to the rear drive at a 45 degree angle, toward the brake shoe side. You will be able to put the splined yoke on the rear drive with your fingers. Then you can rotate the housing untill the bearing studs can be inserted. From this point on, keep the driveshaft end up, or it will slide off the splines, ask me how I know this, too.

Now its is nice to have a floor jack, put the box on the floor jack and guide the swing arm into place, a friend helps here. An alternative is to connect the shock and then by manipulating the jack you can get the swing arm in by yourself. Once the swing arm pivot pins are screwed in you can connect the paralever torque arm. I always try to connect everything possible before torqueing anything.

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