Trying to rebuild a 550 engine. So far so good, but i'm trying to split the case and it doesn't seem to wanna split. Do i need to remove the flywheel before i split the case? And if so, how do i keep the crankshaft from turning while trying to unscrew the nut that holds on the flywheel? Any help would be appreciated! Thanks!

I would just find an engine off craigslist rather than rebuilding. I got a 440 for 80 bucks. I see 550's from time to time on PHX Craigslist..

Or go to SBT they have complete motor with warrant I have put lots of them. Ya can't even rebuild them as cheap as they sell them.

Noah Kruse, on 18 November 2011 - 05:08 PM, said:

If you want to remove the crank you do.

Use a chain wrench.

you need to pull the stator behind the fly wheel, Use an impact wrench on the fly wheel nut, and a steering wheel puller on the fly wheel, the cases are sealed with 3bond high temp silicone. change all 3 seals, watch the rear 2 seal direction, one keeps presure in the other keeps water out.

Noah Kruse, on 18 November 2011 - 05:08 PM, said:

to split the cases you have to remove the primary gear from the crank or the flywheel at least
if cylinder is on impact wrench should do the job
chain wrench also can work on flywheel
and you can put some clothes between the primary and clutch hub gear to lock it up

the flywheel nut is left handed! the puller is 26x1,5mm

sign up on ktmtalk.com there is a section Oldie But Goodie where are thease engines mainly discussed my nick is also rlaci there

rlaci, on 25 January 2012 - 02:38 AM, said:

My friend, this is not a bike engine with a clutch.

The flywheel nut is definitely right hand thread! Righty tighty, lefty loosey.