0-60/100

[cywelchjr]

Here's my concern about the running the engine to 10k to achieve this. I know these engines are stout, but remember, that bearings are becoming pretty much NLA at any price and rings are available ONLY in oversize and pistons are not, and while there IS a big bore kit, I understand they are running their LAST run of those, so parts are getting scarce, which means in the future, custom made parts (I believe there are places that will make almost any part to spec, but they can be REALLY costly), as this is how some of the restorers of really old stuff do it, and it's why it can be so costly, fabricating a full set of custom bearings, and a full set of custom pistons and having a full set of custom rings made (although I understand there are rings that would work if only the grooves were a tiny bit deeper which if you made custom pistons you could do). Engines are still around but they are going to get harder and harder to get in good condition.

This makes me nervous about abusing the engine too much, I consider redline a safe place, the engineers clearly felt it was a safe place to be able to run the engine up to, and I'm thinking even sustained runs up to there are ok as long as everything else is in good condition. But 10k? that's 1500 RPM over redline. Maybe that's not a lot, but it could be the difference between and engine that does 200k and one that does 60k.

[planedick]

Forgot

Maybe I never mentioned it, but I have a complete low mileage engine/tranny here in the garage, and at my age I'm pretty sure this bike is gonna outlast me for sure. The engine in the bike has at least 112,000 miles on it with nothing more than valve adjusting. Compression is 150 straight accross and you will be hard pressed to find one that runs better. It has the 750 final, and 60 mph in first is easy and quick.The excelleration between 3,500 and 8,000 is radical and it's still pulling hard at 10,000. The only thing I worry about is the valve springs pulling the valve closed before the piston comes up and hits it. Usually what happens at those rpm's is the keepers come off and drops a valve which destroys the engine.

[petejw]

i was going to say id be worried about valve bounce,
which planedick talked about, the other thing would be the worry
of the shim dislodging from the valve bucket, but yamaha recommended
changing the buckets/shims so the shims fit under them in instead of on top
for there race bikes but not sure what they revved out too.