We look into most parts that are NLA, depending on popularity. Other parts can often be substituted. Some discontinued MC16 seals for example, while being different to later bikes, can still be substituted with their later equivalents.

The centre seal for the 89~97 motors is part of the centre bearing. We've looked into reproducing the 87~88 centre seal, but the only people we've found who will do it, will not rate them to 13,000rpm, which is what we need. They will only rate to 10,000rpm.

You can check for a "good bad" centre seal with a leak down test, and a "bad bad" centre seal with the fuel-in-crankcase test.

As a very general rule of thumb, providing the bike runs, but runs poorly:

• If it leaks fuel across the centre seal quickly, the centre seal is buggered!
  
• If it leaks fuel across the centre seal slowly, but a leak down test drops pressure quickly, either one way or both ways, it's buggered!
  
• If it holds fuel, but the leak down test drops pressure, it's buggered, and on the way out!
  
• If it holds fuel, and holds pressure, it's new!

_________________
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!