jetting ?

[hondamanforlife]

I think i may need to rejet my 400ex. i have a hmf slip on with stock airfilter, and airbox w lid. everytime i start my 400 it takes forever. i know hondas are cold natured but it takes me prob 4 min to get it running good on choke without gasing it up a lot. i jetted it before, and have jetted other 400s and 450s so i know i am doing it right, i just dont really know if i just jet higher or lower or stay the same to help it start better. after i get it warmed up, it runs great and i have no problems. any suggestions would be great thanks

[bwamos]

Probably a little lean in the idle circuit.

The motor runs leaner when it's cold. Cold air is denser so you have more oxygen in it. Richen it up a little and try bumping up the idle speed about 100rpms.

Your stock pilot jet should be fine. Just adjust the air screw and idle speed.

On the air screw what you want to do is get it warmed up. TUen it all the way in until it seats (richest point), turn it out slowly with the motor running. You will notice the engine speed increasing. Keep turning until it stops turning. THis is the optimal a/f ratio 14.7:1 Turn it back in (richer) a 1/2 turn for saftey. Don't want it to idle hot. ;)