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redrider_1220
10-11-2005, 06:58 PM
I have a 2002 400ex. The motor is completly stock other than an IDS exaust. It blows out blue smoke when you start it but after it gets good and warm it quits or at least I haven't noticed.

It is also using alot of oil. I filled it up last time I rode for about 3 hours and I checked it a couple of days later and it wasn't even showing on the dipstick.

My question is do I need new rings, piston, valves, or what? If I need a new piston what compression should I go with?

Thanks, any help would be appreciated.
2004exrider
10-11-2005, 07:08 PM
welcome to the site, sounds like your valve seals are bad. alls its doing is leaking oil in the cylinder when its sitting and when you start it it just burns the amount of oil thats in there.

Jimmy
tater_kamik
10-11-2005, 07:58 PM
does it do it when you rev high?
redrider_1220
10-11-2005, 08:23 PM
Yes it smokes more when it is revved
exracer131
10-12-2005, 11:28 PM
i would also say your main problem is in the valve seals. it would be in your best interist to go ahead and rebuild the top end anyways. why i say this is; when you take the head off your will break the seal on the cylinder base gasket, there fore you will need to removed the cylinder to replace the gasket. so since you got the top end tore down why not rebuild it. i myself would go with a 10:1 piston just for the fact 92 or 93 octane will work fine in that engine.
limetimeracerII
10-13-2005, 06:47 AM
actually on the 400ex the head studs don't hold the cylinder down. It has seperate bolts that hold it down. So you won't break the base gasket seal if you take the head off.
Travis712
10-13-2005, 08:36 AM
But would valve seals affect it when its revving high? I understand the sitting part?
tater_kamik
10-13-2005, 09:27 AM
sounds like your rings to me...
ridinthedunes
10-13-2005, 09:53 AM
3 hours of riding and it didn't read on the dipstick??????
hondajoe05
10-13-2005, 05:22 PM
wiat maybe your valves need adjusted real badly or your rings came off cuz that burn a **** load of oil mine did and it doesn't go away tho and it costs a **** load if you keep riding it so i would stop
tater_kamik
10-13-2005, 05:28 PM
that really is a lot of oil... you definately need to take your top end off atleast. or take it to a shop and see what they think, have them do it if you arent comfortable with doing the work yourself
Sleeper
10-13-2005, 06:40 PM
general rule of thumb on smoking is that valve seals will make you smoke on start up and on deceleration. they make it smoke on decel because you are pulling a vacume that can suck oil through the intake valve seals when the throttle is closed and the engine is winding down. Rings normaly make it smoke on acceleration. course if the rings are bad enough you could pretty much smoke constantly. either way it's probably time to freshen up the motor. Time for a mod!



sleeper
ridinthedunes
10-13-2005, 07:05 PM
he said it only smoked during warm up.....but to use that much oil if it's only smoking for a few minutes.......????
Did you try checking the plug to see if you could get the other cylinder to fire???
proff x
10-13-2005, 07:12 PM
my friend had the exact same problem with his 2004 400ex he had a yoshi pipe and his ring were shot i would say rebuild the motor or make it a 426 if you want my friend payed $70.00 at the dealer for the bore and $100 for the piston and $17 for agasket kitid tell you how it ran but my friend tourque the bolt on the head down to much and snapped it but it was easy to take ap art and rebuild just WATCH and make sure your on the compression stroke and the cam is linned up. A clymer Manual is very helpful on the entire thing
tater_kamik
10-14-2005, 03:52 PM
Originally posted by ridinthedunes
he said it only smoked during warm up.....but to use that much oil if it's only smoking for a few minutes.......????
Did you try checking the plug to see if you could get the other cylinder to fire???

at the beginning of this thread, i asked if it did it when he revved it up, and he said yes, it does. also, there is only one cylinder on an 400ex, so what do you mean by the other cylinder?
Travis712
10-14-2005, 03:58 PM
Haha..thats a good question.
Chicksdigme423
10-14-2005, 08:14 PM
he said it only smoked during warm up.....but to use that much oil if it's only smoking for a few minutes.......????
Did you try checking the plug to see if you could get the other cylinder to fire???


dude, 400ex's only have 1 cylinder what are you talkin about?
ridinthedunes
10-17-2005, 12:23 AM
oops....was also involved in a thread for aircooled vw's and a guy was having problems with #4 cylinder.....got the two mixed up.....guess I should look at the other thread and see if I wrote anything stupid there :rolleyes:
fitethesystom
12-20-2005, 11:54 PM
join the smoking 400ex club.... i call my bike smokey. I'm gonna throw new rings & valve seal's and see what happens. God I hope it stops.

Mike,