jetting

[Civiblu]

I have a yz250, I am trying to cleanup the carb and I wanted to adjust the jetting. from 1/4 throttle and up it smokes quite a bit and bogs I was wondering which adjustment would u start with the main jet or needle jet position. I know the main jet is 3/4 on so I wasnt sure if that was it. Once the bike warms up the engine clears out and up to half throttle its clear afterwards it bogs and smokes, any help is good thanks.

[Levi]

Smoke? Inevitable. What premix ratio are you running?

Have you done a compression (static) check latley? What's it at?

Bogging after 1/2 throttle? If it's jetting, needle clip position and main jet.

Have you done a plug chop?

Another possibility; ignition could be the problem. What are you gapping the spark plug at?

If it's actually jetting, try raising the clip one position on the needle (ie. if it's in the 3rd groove now, try the 2nd). Also try dropping a size on the main jet.

[Civiblu]

I put a new plug in the last one had a lot of carbon build up. Is it best to try down one size on the main jet first and try that before adjusting the needle jet? or can you do both

[Civiblu]

the premix ratio is 40:1 I have to check how i mixed it last, I remember it was 5 gal to 16 oz.

[Levi]

To be completely safe I would do one at a time. Try adjusting the clip position first. See what results are yeilded.

What's the compression at? I know that if you have a tired top end, it makes the job of getting jetting spot on a little harder.

[Civiblu]

Im not sure what the compression is at I don't have a gaugen yet, but it feels [retty good, theres a good amount of resistance when turning it over. Thanks for the help