new member with a ?

[Hondarider400ex]

i have a 2001 400 ex...its ruff starting up less its got jumper cables on it...im guessing needs a new battery but once its warmed up there is no problem with it starting. Recently after it warms up if i hit throttle hard a flame will come out of the exhaust and it will stall out. I was wondering if this couuld be carb gunked up or maybe the jet going bad?shoot me your guesses please

[TRX2fiveO]

Welcome to the forums....

The battery would be my guess, as far as the backfireing goes is it cold when itdoes this or does it do it all the time? if cold i would say your rich and it's loading up in the cylinder and detonating when it comes up on stroke to fire the plug and hitting the throttle adds more fule to the chamber. What kind of mods have you done to your quad?

[Hondarider400ex]

well i bought it used its got dg full exaust aftermarket blue?? yamaha racing plastics..and cept for the sprockets and chain that i replaced im not honestly to sure what all he did before i got it. I had it for about a year now!

[Billy250X]

Clean the carb good.If it just started recently something had to have changed.Probably just junk on it.

[Hondarider400ex]

how would i go about fixing what u said up there if that does happen to be the problem

[Hondarider400ex]

thanks billy thats what i was going to do..just wondering if there was something else i could check while i was in there dickin around

[TRX2fiveO]

jetting may be your issue that along with a dirty carb...like Billy said take it off and give it a good cleaning with some carb and choke cleaner

[tomgodd]

Welcome to the Family!!

[shadetree]

yup..start with a good carb cleaning..if that don't work..you may need to over haul your carb with new jets.

[mud99]

Welcome to the forums