Until recently, crank bearings for the NSR were even rarer that the proverbial rocking-horse sh!t, as neither Honda nor Koyo (the bearing manufacturer) would supply them!!!
Consequently, NSR cranks were labelled as non-rebuildable, and the only official answer to wear and tear and/or seizure, was to buy a complete crank assembly direct from the big "H".
Recently though a small stock of main bearings has become available from a supplier in Australia, and a link for them can be found on both the homepage and at the very top of the Classifieds page.
Needless to say then, the NSR crank CAN be pressed apart, and new bearings installed, but it MUST be done by a reputable engineering shop - preferably one with mucho 2-stroke experience! Tuners such as Bob Farnham and Terry Shepherd spring to mind! Only recently has one owner in the UK had his crank rebuilt with alternative (to the Koyo/Honda) bearings by Chris Appleby, but his motor has yet to be used in anger!
So, the latest word on the street is, "yes - the cranks CAN be rebuilt, and yes, you CAN get main bearings!", but... there is still no known supplier of big-end bearings although there must be something out there suitable as they most likely won't be unique to the NSR.
Andy.
NSR-WORLD.COM