no top end

[tntinc]

quick question, i have an 88 rm250, 150 or so compression ,new plug and im deffinately getting spark. so the question is after about 2/3 throttle to full throttle it basically dies until i let off then it will pick back up but i have basically no top end. It has a fatty pipe and silencer, twin air filter, after market reeds of some kind. i cleaned the carb and checked the jets, the pilot was 5 under,a 15 and stock calls for 20. my needle is in stock location, 3rd from top, but my main is suppose to have a 370 but it had a 320. i just put a 370 in and theres still no topend. i did find that my exhaust valve rod was unhooked and i thought that would do it but it still has problem. i did the rooling spark plug test and the plug was wet. could it die being too rich. sorry its so long

[burgiebird]

Yes it could be too rich. is it smoking like hell? If the plug is wet try a 300 and go down from there. Careful to not go to low. Check air filter and leaks in the intake.

[tntinc]

i appreciate it, i was under the impression that with the pipe I would be at stock or above on jetting, I have a 320 that ill put back in, any advice on an irradic idle? Ive been toying with the air idle screw but no luck, if the reeds are in less than perfect shape could it affect the idle that much?

[burgiebird]

Yes they can but it sounds like there is a leak in the motor somewhere. let it sit and idle and spray carb cleaner or break cleaner on the intake boot and engine to see if there is a leak. If it shuts down or revs up you will know where the air leak is.

[tntinc]

wouldnt the compression drop if there was a leak?

[drag lt guy]

not nessicarly. it will make it run like shit and you will hurt the engine almost 100% of the time

[tntinc]

what is the most common leak, itried the brake cleaner all over and it never revved up. it runs good up to about 2/3 throttle but it does idle crappy, it will idle fine, then drop, then idle high and so on