Sherpa Fork Rebuild

[d250b]

Just about to embark on first ever attempt at rebuilding the forks on my M190. Is there a proper sequence in which to do this or is it pretty self-explanatory, are there any tricks to doing it??

The M8x35 allen headed bolt on the very bottom of the fork leg has two washers, one is a star/lock washer but what should the other one be made out of? copper or fibre. There was a fibery sort of stuff stuck to an ordinary plain washer when it came out but the whole thing was gunked full of silicone as well. i'm a bit concerned because now that I've gotten all the silicone out, the hole is much bigger in diameter than m8, is this correct??

also i think i remember reading that the double seals both go in the same way unlike the back-to-back ones on the crank case?

cheers

D

[pschrauber]

The bolt at the bottom should have a fibre washer seal, instead of a star lock washer it should be a split lock washer, at least that is what I found in four different Betor forks for Bultaco and SWM.

To trick and tweaks:

You might look up if the stanchions a straight. As straighter they are as better works the fork.

The double oil seals wear pretty fast in my experience, you might switch to ariate fork seals which have an extra dust seal on top,

just one seal per fork leg, the come from the KTM SX65, they work very smooth 'cause of less friction.

If the spring is worn out you can replace the spring against one from Magical which is more progressive too.

The piston in the inner rod has a wrap with a fibre bush, this might be worn too it should then be replaced.

For reassembling and tightening the lower Allen bolt you might complete temporary mount the fork spring and the upper fork nuts

so you have enough tension on the inner fork piston/rod ... or you use an old wooden broom stick, works too.

[d250b]

Thank you pschrauber!

I seem to have managed it without too much difficulty

The stanchions were secondhand ones which I have had rechromed, (i discovered that my originals were different lengths as well as being pitted). It took a while to get them back but the new tubes look superb. I understood that part of the process done by the rechroming company was checking for straightness.

I had already purchased the double oil seals as well as new Pursang-length springs. I don't have the brake fitted yet and the bike is still on the stand but I can't wait to see what it feels like now that it's all done.

Even the allen bolts went in without too much trouble and whilst I didn't use a broom stick I managed to stick another tool down there to stop it turning but it didn't take much.

So far there has been no leak but I'm still not sure if the size of the hole in the bottom of the fork leg should be so much bigger in diameter than the allen bolt? it seems to be asking a lot of the sealing washer????

I took your advice and got some fibre washers which were a wee bit too big but managed to file them down carefully to fit the recess. Perhaps it was the type of split washer i had but when held against the fibre one I was convinced that it would tear it when tightened so i have tried a flat washer and some thread-locker.

I have discovered so many stripped threads so far that i was too scared to try and tighten the bolt to the required torque so it's in there as tight as i dare for the moment and we'll see how she goes.

cheers

D

[bondy]

hello thick i used a flat washer and a fiber washer i tightened the Allen bolt up with a electric in pack gun did't need anything to put down the tube to spot it turning the in pack gun winds in fast. the other way is there's a slot on the damper you can use a long flat screwdriver if you have 1 it's a big hard to do this way on you'r own. but you have done it now so sorted.