Top-end problems

[Melton69]

Hi, I have an 86 250r, all stock except a pual turner mx pipe. When I am riding the quad and i get to the 3/4-full open throttle the motor bogs down and wont go above that rpm. I know that a big tattletail to this problem is the main jet. I have switched it from 155-178 and everything in the middle and it just doesnt affect it. I have tried moving the length of the jet needle and all of that tinkering never fixed the problem, I had it were it was alot better but it just wasnt right. Does anyone have any ideas about fixing it? Any help is greatly appreciated.

did you check the reeds?

[Kirt13]

Did you recently make any changes to your motor, intake or exhaust? Have you had it sitting for a long while?

spark plug may be fouled. You may be running too rich. Put a new plug in and ride it for a little while. check it and make sure it has a nice brown paper bag color.

[Melton69]

It could be the reeds, I bought the quad last year and dont know if the reeds are stock or aftermarket, they are carbon fiber though. When I looked at them they look very clean and new, no cracks, however, i dont know what to look for when it comes to them.

I havent done any engine work, and its got a full aftermarket exhaust, but the quad had the problem when I bought it and I am not sure if it started happening right after the pipes were installed.