Whip the flywheel cover off and give the flywheel a good man-handle! Sit on the bike and reach down, and rock the flywheel up and down. Turn the flywheel 30° and repeat until it's gone through 360°. It's not the definitive test, but you can feel even very tiny play. Any play at all would suggest the crank is on the way out, and if the crank is on the way, then the centre seal is almost certainly shagged!
Sorry, but it how it is! Mine went on for ages, and right up until just a couple of months before we pulled it apart it would scrape 60hp, but it was rough as hell!
Goes like a rocket now it's rebuilt mind you!!
_________________
Andy.
NSR-WORLD.COM
Please keep all responses to Forum posts on the Forum so that others may benefit.
Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.
Check us out on Facebook! Please "like" our page!