in 1st and 2nd gear i have popping and power loss while reaching upper rpm's. 3,4,5, gears run normal.

any suggestions?

going crazy in vegas


2003 honda 400ex

 

just a guess but it sounds like a carburator, or fowled plug.

 

yah sounds like a carb problem to me too. does the bike have a jet kit in it already?

 

i do have a dyno jet stage 1 kit installed, with a white brothers pipe.

i had removed the carb and cleaned, as well as replaced the plug, but still have the same problem. I am noticing alot of soot around the end of the exaust pipe.

 

Sounds like a classic case of a clogged slow jet! This makes you lean overall, but especially on the bottom end. Fuel probably dried up in your carb and left scum in your jet. When you cleaned the carb, did you pay any particular attention to your slow jet. (Most folks concentrate on the main, and don't even realize they have a slow (idle/pilot) jet.)

I'll take a guess here, and seeing that you are in Vegas your quad mostly sat during the summer months when it was to hot to do much riding. Now that things have cooled off, you rolled it out of the garage and discovered a problem.....