Mikuni TM33 jetting....
 

I did the 351 kit from Bill Blue. I also bought the TM33 pumper carb. The assembly went well. Bill noted that the carb was jetted 40 pilot and 140 main. I also ordered an FMF Q4 exhaust. When I started the bike, I had the stock exhaust. On the first test ride, there was bad hesitation. I worked on the needle and got the idle good and it helped the hesitation. I still would not pull more than 7500 RPM. I decided to wait for the exhaust and Bill Blue advised that I should try the 142.5 main. Both went on today. I still have the hesitation and it will not pull more than 7500-8000 RPM. Any suggestions? Thanks,
Don

2006 KLX250s, 351, TM33, 40 pilot, 142.5 Main, FMF Q4.

Take the air box lid off. If it runs better, go lean. You need to post your elevation.

Thank you for the quick answer. The elevation is 1200 ft. I pulled the snorkel before I went to 142.5. It ran better without the snorkel and with the 140 main.

Right now I am running a 130main/32.5pilot/2.75ish turns out@3300 elev. I have no mods other than 351. It is running great up to 12000ft.

I have basically the same setup as you - 351, Tm34 with fully Muzzy. I'm running a 40 pilot and a 145 main. Elevation is about 1300 - runs great through the full range.

I'd try to be a little rich over lean, especially at break in.

Jeff.

Hey - does the Q4 come with a bigger head pipe?