Splitting cases on a YZ 426

OK so long story short, I need to replace a crankshaft on my bike.

I am planning on doing the work myself, as I have done top ends before and watching videos online i think i can do it as long as im careful... hopefully haha.

My question is what miscellaneous parts will I need? I am going to replace the left half of the crank ( the part that the flywheel ultimately bolts to).

Should i be getting all new crank bearings too, and any other stuff i may be overlooking? It is a 2001 after all...If anyone has split cases on a four stroke before and has some insight please chime in... Thanks!

I did my 426 in april. I would replace any warn bearings. Do yourself a favor and replace all the oil seals along with the gaskets. Goto youtube and search johnnyshop. He has excellant videos of a 250f rebuild. The motors are the same design.

You will need a torx bit, can't remember the size. It's to remove the timing/stator plate to remove the counter balance shaft.

you need a Yamaha service manual. not a climer or any other cheap manual.

the Yamaha manual gives details on removing the motor, gives specs on everything.

you can pull everything apart in a way that you can remember how to put it back together (notes, pics, whatever helps) once you got everything apart you can makes a parts shopping list and order everything at once.

This is the only way to do it. if you only buy bearing a and b... you could find yourself half way done with the rebuild and need more parts.

thanks grayracer, the manual is going to help so much, the bike came with a clymer, and using one of those for reference is like shooting yourself in the foot trying to prepare to run a marathon.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now