How to replace the shaft seals and fork oil on an XS400
I put the bike on a downslope on the center stand so the front wheel would be off the groubd
Loosen but don't remove the 14mm pinch nuts. I also loosened but didn't remove the JIS/phillips screw above it.
Remove the 2x14mm bolts holding the caliper on, then remove the cotter pin and 22mm castle nut on the axle.
Support the wheel with your foot, pop the axle from the right with a rubber mallet to push it out. Remove the wheel
Use a 6mm Allen wrench to loosen the bolt holding the fork sleeve on
I has to use an extension on the right side. Again I did not remove the bolt yet, just loosened it while the fender is keeping the forks together for better leverage.
With both 6mm hex bolt loosened, I removed the 4x12mm fender bolts and removed the fender, then removed the left sides 6mm bolt. Make sure you have a drain pan underneath the forks at this time, because oil gushed out. I took the copper washer off and ran both sides across 400 grit sandpaper laying on a level surface. This helps even it out so it can act as a gasket when installed and tightened.
Fork cover removed. Removing the old shaft seal was a pain in the ass. First use a flathead to remove the little clamp. Then, brace the bottom of the fork cover on the ground and use a big flathead as a lever. I focused on one side and eventually it came out, but it took a while. The right side one was even worse.
This metal washer thingy is below the shaft seal. It just drops out. I cleaned it up and put it back, rounded side (pictured here facing up) goes DOWN when installed back into the fork cover. I rubbed a little bit of oil around the outside and inside of the new fork seal, reinstalled it, and popped the clamp back in.
Instead of reusing the ancient, cracked dust covers, I installed these gaiters instead. I need to put a hose clamp across the top but I'll do that later. I might even just zip tie it.
At this point, the fork cover just slides back up the fork, then reinstall the 6mm hex bolt. Once I had both hex nuts installed loosely, I put the fender back on (loosely still). With the forks more or less parallel, I tightened the 6mm bolt. I loosely installed the 14mm pinch nuts, then propped the wheel up in my foot, making sure the speedometer was oriented properly, slid the axle through. Tighten the pinch bolts to 14 ft/lb, then tighten the axle castle nut to 70 ft/lb.
At this point I did the brake pads. This pic was just for reference on their orientation. The caliper honestly needs to be rebuilt, but I don't have a kit for it yet, so once the new pads were installed I put the caliper back on and tightened the 14mm caliper bolts to 25 ft/lb
I think it looks pretty sharp with the gaiters. I'm taking a break for lunch then putting the new oil in. Total time so far is just under two hours.