PDA

View Full Version : 400ex, backfires, no power


mickey400ex
10-19-2006, 08:47 PM
my buddy has an 01 400ex, now i rode this thing a week ago and it would barely pull me around, it has no power whatsoever, its not smoking or anything so i figure the piston/rings are still good, hes changed out the plug, cleaned his carb and air filter, now he is saying it is backfiring some, does anyone think it is carb related or something to do with the cam, or maybe even jumped time?
cals400ex
10-19-2006, 09:24 PM
will the engine rev and not go? if so, look into a clutch. if it wants to die, look into the carb. make sure the mainjet did not fall out of place. that is fairly common. also, make sure the needle clip is still on the needle. i have seen those break before and cause similar problems.
mickey400ex
10-19-2006, 09:53 PM
it will rev, but it wont rev out, and it didnt want to die out or anything
Xater
10-20-2006, 06:21 PM
sounds like spark plug
cals400ex
10-20-2006, 06:27 PM
so it didn't spit and spudder at all? and it revs out fine? are you sure the brakes aren't stuck or something?
ilpadrino113
10-21-2006, 10:38 AM
the breaks could be set too tight, or one of the jets could have fallen out.
mickey400ex
10-22-2006, 05:38 PM
he changed the plug, and the breaks are fine, it didnt sputter when i rode it last week, honestly i could of got on a 350 rancher and smoked it, he said he took the carb apart and checked, but maybe he doesnt know what hes doing, anybody got anything else?
NY06400EX
10-22-2006, 06:51 PM
If the brakes are fine and it truly isn't engine/carb related (although imo I think it may be based on the description - backfiring etc) check the "free spin" of each wheel. Make sure there aren't any bearings that are hung up etc. Check the chain for slack, the sprockets for missing teeth, the throtle cable for wear, the clutch cables and clutch for wear, besides changing the plug did he check for spark? - check general maintenance stuff like the items I listed.

You never know, sometimes the cause is an overly simple one... at times we all have assumed issues are more involved and overlook the basics. Just my .02.
ilpadrino113
10-23-2006, 08:01 AM
get a compression tester and what the comp is
10-23-2006, 08:06 AM
I think its the elec. mine ran bad and backfiredand stuff and i found out my elec connection was loose. Are raptor did the same b4 and it was elec too.

My hybrid was hard to start and would pop when i gave it throttle and had no power. I kept thinking it was the carb but couldn't find anything wrong. I found out my cdi connection was loose and as soon as it was tight again i had all power back and no more poping.