Honda 400x Dynojet

[rich1]

The FMF muffler for the 400 x came with a Dyno jet kit . I was not really excited about using them in a Keihin carb. But the QB ( EPA ) carb is very fussy about jetting and hard to get right. The jet kit uses a different needle too . You have to use an adapter to even use their main jets, good since they flow different from Keihin. However the kit has stage 1 and 2 settings and include a lot of jets, for air flow and altitude adjustments. My richer pilot jetting has cured the cold start (lean) problem. Instructions are detailed and easy to follow. The plug looks good after a few runs up the street. So far so good for a $50 kit.

 

[rich1]

So the 1st ride of the year was good. The Dyno- jet kit gives the 400x more power in midrange and top end. Still using the one step colder plug and it has not fouled yet. The motor seems happier with the extra fuel and seems to running a little cooler. I think that the needle that came with the kit made the most difference.The jets are calibrated different than the Kiehins too. Keihin carbs have never been able to run well thru the throttle ranges except on top end. They have always been a on or off sort of carb . However once you get the mid-range right ,like this kit does, the carb really shines.

 

[Larry's Shee]

Glad it worked good for you.


F the EPA