2002 w/ 80,000 miles
poor power wide open.  has a sweet spot around mid throttle where power is best.
Opened it up to clean it (main circuit dirty somewhere?).
While cleaning the slider diaphragm (soap and water), I found 3 very small cracks in the creases of the rubber.
Clymers says to get rid of it.  At about $120, that would be a hell of a hit!
Opinions out there on how much impact this is having on the performance, or does that diaphragm not really do much of anything?
Other options.  Replace diaphragm or go with a used carb from fleabay?
This is a Mikuni 38mm, but what flavor do I look for?

Thanks!