i recentley put a new piston and small end bearing in my bike but i want to rebuild the bottom end i was wondering how much are looking at for the crank bearing and various other bearings and is it easy enough to get the old crank bearings out or do they need to be pressed out ??
Depends how the motor has been treated but generally about 15k miles upwards probably. Worn main bearings make a rumbling noise when the engine is running. Also, take the left hand generator cover off and grab hold of the flywheel. If you can detect up and down play then the mains are worn and need changing. You must change the seals at the same time. I use bearingboys.co.uk which from memory were about £25 each bearing. Its a crap design as Yamaha have taken a cheap standard bearing and machined 1mm off the width which has made it a special and therefore much more expensive. No idea why they have done it but there are very few places where you can get em.
Through Yambits (ebay) i have recently ordered a full set of seals, Long conrod kit, and koyo crank bearings, all together it came to about £105 delivered.
