View Full Version : my 400's got me doun
1fst400
04-18-2006, 07:10 PM
today at the track it seemed as tho my 400 was constantly dogging out. low on power. and missfiring on top end.
I suck at jetting. Im running a fcr carb, im running a 175 main. time to go bigger on the main. hasent been running right scence I installed a higer comp piston.
Ex'r Marlin
04-18-2006, 11:55 PM
Question:
Are you running a stock exhaust?
If so, try running your atv without the airbox lid and see if that makes a noticeable improvement.
If that makes an improvement, and/or you need it to improve even more, you most likely will need to go with at least an aftermarket slip-on exhaust to allow more air flow through.
Note: Once I went to a higher compression piston (10.8 to 1), it did not matter what jets I put in it... The atv ran terrible until I put a slip-on exhaust on it. BINGO... Problem solved.
Best wishes with your first atv!:macho Congrats on getting a HONDA!:D
EXevan91
04-19-2006, 09:17 AM
what is the comp ratio on the piston u installed ?
1fst400
04-19-2006, 01:54 PM
12:1 je piston. and everything eltse, 416 bore
CHEVYZ
04-19-2006, 02:34 PM
What kind of fuel are you running?
1fst400
04-19-2006, 05:32 PM
vp red.
the answer Im after is does missfiring on top end come from bad jetting or is my problem eltseware.
CHEVYZ
04-19-2006, 06:33 PM
Try rejetting with a little bit larger on the main and see if it helps any. You may have to play with the tune for a little while to get it just right. Misfiring on the top is an indication in most cases of being a little lean.
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