i have a honda trx 250 1985 i did some stuff to it look and see a bottom what is the max rmp i should be running

 

They have a rev limiter. Max rpm with the rev limiter is around 8,500.

 

ok thanks i have a tach on it on the highest i got was 8970

 

Regarding your last thread, are you running race fuel. With a 12:1 compression ratio, and using regular pump gasoline, that could explain the overheating problem you are experiencing. There is no choice in this matter. If you want to run high compression then you also must run the higher priced and harder to come by racing gas. Your new piston will soon have a hole in it (from preignition)if you don't heed my advise! If none of this makes sense to you, dump that piston now and return that quad to stock.

 

irun i high octane fuel i ran about a 105 to 110 i get it from pump but i boost it up to 105 to 110

 

Sorry, but an octane booster isn't race fuel. Not even close.

We'll repeat it for the 5th time (you've had five other answers from different people stating the same thing in the last month)

YOU MUST RUN RACE GAS WITH A 12:1 PISTON.

Not octane boost. Race Fuel. VP, Trick, S&S, ELF. Whatever you choose, but it must be at least 108 octane and leaded.

No if's ands or buts - anything else will cause the detonation you are experiencing.

I guess it doesn't matter if you listen to our advice or not, you'll learn about detonation and octane soon enough when the bike seizes or doesn't have enough compression to start.