Hi everyone,

I am in the process of replacing the mains/crank bearings and seals on my 2004 Sherco 2.9. And I am having real trouble with the new crank seal on the primary gear side.

When I try to reinstall the crank assembly into the clutch side crankcase (having oiled the seal surface which will be in contact with the crank shaft), the crank shaft on that side distorts and pushes the middle of the seal outwards. I can't seem to push the middle of the seal back into the correct position/shape and feel that if I eventually do, the force needed will damage the new seal.

The seal is the correct size - as supplied by MRS.

Has anyone ever encountered this problem and if so, could you tell me the fix?

Thanks very much

Edited April 19, 200719 yr by gasgasjools

I've done a few of these some time ago and have always replaced the bearings.

I'm trying to think of the procedure and I'm fairly certain I put the crank assy back into the crankcases first, then I put the seals afterwards. You might like to check if this is possible, as without the engine stripped down in front of you it's difficult to picture accurately.

Hope this helps

Hi there,

I've replaced many main bearings and seals over the years, but never worked on a Sherco. In all cases, except for the PRO motors which have the crank seals inward of the main bearings, the seals go on after the crankcases have gone together, never before as they are then subject to damage.

You might find that on the primary gear side, there is a sleeve perhaps of some description that acts on the seal or maybe the seal acts directly on the crankshaft. Make sure the spring on the seal faces inwards to the crankcase, fit the seal after the cases are put together.

Bye, PeterB.

The seals are different on 1.25-2.0 vs 2.5-2.9, wiich means you better ck the size to be sure they did not get mixed!

Thanks for the info guys,

I will give it another go tonight - remembering to put the seal in after the cases are fitted back together.

Thanks again

Jools