If the centre seal is shot, you are completely out of luck. They are not available, full-stop. Your only alternative is to find a crank with a good seal, even if the rest of the crank is shot, and have one rebuilt.

We have to reuse centre seals (although we have some alternative seals to try, but the manufacturer won't rate them to 12,000rpm like the Honda ones), but we are not prepared to use them in customer cranks that we put our name and reputation on.

We've rebuild 87~88 NSR, HRC F3, and HRC RS250 NF5 cranks reusing [good] centre seals (the customer is always informed that we reuse the seal), and we've never had a failure. The seal must be perfect though, or we write the crank off.
_________________
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!