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trx400ex
08-26-2001, 07:37 PM
alright guys ...400ex bought in march 01 is 5 months old 5x30=150 days old...ive ridden it about an average of 3 hours a day 3x150=450 so it has about 450 hours on it..the other day i was ridding and it started to smoke blue ...i washed it off put it away and took it out today....i had my friend ride it while i watched and it smoke a little...(btw it was all out of the pipe)..does anybody hereknow if it would need a rebuild alread? if you do please help me out...thanks a bunch

nakomis0
08-26-2001, 07:45 PM
You wouldn't think it would need a rebuild. Maybe its time for an oil change.

skemp
08-26-2001, 08:08 PM
I think it might be the oil too. It will break down and possibly cause the engine to smoke after it gets very hot or is worn out.

It could also be damaged or worn valve stems or guides. This could let oil seep into the combustion chamber and burn. Another problem might be leaking valve stem seals. Blue smoke usually means oil is burning.

I would first change the oil and oil filter and see if that stops the smoke.
If the oil and filter change doesn't stop it, you could try to get a compression tester and see if there is low compression. This could mean a seal, stem, or guide is bad. If that yields nothing, take the cylinder head off and visually inspect the valves and other parts to look for wear or damage.
Good luck!

trx400ex
08-26-2001, 08:32 PM
thanks guys but the oils only been in there for 3 days :)....is it possible i might need a rebuild...i really wish i would cause then i can modify the whole engine cam, 440, carb, port etc,,,,my dad doesnt want me to screw up a "perfectly good" engine haha any other i deas thanks

08-26-2001, 08:38 PM
you can't find a valve guide,seal or anything above the valves with comp. test cause valves are closed on comp. stroke

trx400ex
08-26-2001, 08:44 PM
what?

skemp
08-26-2001, 08:51 PM
Originally posted by McgrathSucks
you can't find a valve guide,seal or anything above the valves with comp. test cause valves are closed on comp. stroke

True, but if a valve is bent or distorted, you would find low compression. If they don't close all the way, oil will leak into the cylinder whether it is intake, compression, combustion, or exhaust. I have heard from my local Honda shop that they have seen a couple instances of bad valves right from the factory. A guy that used to work there as a mechanic told me one guy brought his motor in with one exhaust valve jammed shut. Turned out the valve broke clean off and the spring, retainer, etc. were bouncing around inside the cylinder head. The guy apparently tried to run it home like that. :huh