400ex jetting question

[jmonje]

I recently bought a 2001 400ex with a ProCircuit t4 pipe. The guy I got it from said the pipe had been installed and the carb rejetted by a local shop. The bike looks good, sounds good and runs good. I got a k/n filter, Dynojet kit, and EHS airbox cover. But when I pulled the old main jet from the carb, it was a Keinin #140????? , with the needle set at position 2. I put in the Dynojet 170 and dj needle (position 3), but it bogged at full throttle and the floats overflowed. I tried the dj160 with the same result. I am now back to the Keinin 140 and the Keinin needle. Seems to run better and the floats don’t overflow anymore. I will talk with Dynojet later today. Is it possible that I have a 300ex carb? How do I tell? Any advice will be appreciated. Thanks!!

[vze2hnvz]

170 dynojet is way too rich for that setup, even the 160 dynojet is a high. A 170 dynojet = 190 Keihin. And a 160 dynojet = 177 or 178 Keihin jet. If you have a 142,144,146 dynojets, try those and do a plug chop test. Should get you a little closer. If a 140 Keihin jet is in there now, thats too lean considering the stock main jet is 148 and with the mods you running. Start with the dynojet 146 and work your way down if it's still too rich.

[jmonje]

thanks - the dj146 is pretty close. i have the dj needle @ pos 3 and the mix screw out 3 turns. also the floats are NOT over flowing. i will check the plug and go from there. i really appreciate your help. i did talk to dynojet on the phone today - a total waste of time. you know more about their product than they do???

[vze2hnvz]

As with any company, the amount of help you get depends on the individual your talking to. You could call back 10 minutes later and get a carb guru - luck of the draw. Glad I could help... ;)