Project Operation Fzr250 revival

OK, rebuild parts are difficult - first point

Head gasket available ~$38
Bearing shells - TBD - it's a BIG topic and I have some more research to complete the puzzle for OEM alternatives
Conrod bolts use Kawasaki ZXR250 bolts
Gearbox output shaft bearing NLA - I have an alternative, the other 3 transmission bearings are a walk-in to the bearings supply store

BUT, before you tear it down, check the clutch basket, the rubber dampers will be hardened - get some 0.4mm gasket paper to cut your own gasket in case it tears on removal.

Here are my links
https://www.2fiftycc.com/index.php?threads/1993-zzr-250.8957/page-4#post-113608
https://www.diymotofix.com/blog/how-to-repair-your-clutch-basket-dampers-for-less-than-30
https://thumpertalk.com/articles/what-causes-a-worn-clutch-basket-amp-how-to-fix-it-r282/

Now removing the clutch basket rivets, drill the heads, the push out with a marking punch, they are 4.2mm diameter so a 5mm 0.8mm thread can be tapped directly

NOTE, the rivets do not hold basket 100% tight to the primary driven gear, there is a tiny bit of clearance to be able to move to absorb the ignition pulses
So replacement screws would need to be tightened with something to keep clearance [then removed] and using red loctite

NOTE - on the bearing shell issue - I have done a lot of research, need to make space in my garage to complete my measurement, then hopefully I will have a full compliment of OEM [Suzuki, Honda & Kawasaki alternatives] as everything Yamaha in that dept is basically NLA

Last thing to mention, they are noisy engines, you've got exhaust pulses, intake pulses, the ignition pulses causing the primary driven gear and transmission to make noise.

If you recall that OEM side fairing that I gave you has sound absorbent foam, it's there for a reason...