Blue smoke from muffler when revving engine?

[EvilJester400EX]

Well, I was practicing today and my dad noticed that when I was revving the motor blue smoke was coming out of the muffler. What could cause this? Are my rings going bad? Would it be a bad idea to race it on Saturday? The smoke isn't rolling out, it's just like little puffs.

[jokerman_28]

what kind of oil are you using. try changing it.

[trailburner]

If its blue its oil.....:( check your plug if its black and wet your rings are prob starting to go. but before I would tear into it I would have a compresion test done just to make sure....

[chrisp333]

blue, grey , white, definately oil

black to rich

[EvilJester400EX]

Well, I just came back from the Honda shop, needed a service anyways. They said it wasn't anything to worry about, but they'd look into it and see what the problem is.

mines always done that, i see brand new stuff do that, as long as its not using alot of oil ur ok, it could be valve seals or rings or old oil but dont freak out

[sparks400]

Originally posted by freeride132
mines always done that, i see brand new stuff do that, as long as its not using alot of oil ur ok, it could be valve seals or rings or old oil but dont freak out
ya thats what is probuly happening ur gonna need some new vavle seals, cuz my old 400 did that before i got rid of it, but it could also be rings, or u need some new oil. do a plug chop and see if ur plug comes out wet and if so u should check ur rings. good luck

[nacs400ex]

I can almost gaurantee its your rings ( I believe the oil ring) on your piston. My 400ex was doing the same thing, whiped a set of new rings in and its good as new. Oh yeah, it could be your valve seals too. The ones on my 400ex were looking a little harsh, so we decided to change them too. Take it apart and you will find out:)

[speedy]

well my 400ex smokes when revving also but it also uses alot of oil. What does this mean :confused:

[cals400ex]

i would try changing the kind of oil you use first off. if that does not do anything, it is probally your rings or valve seals like mentioned previously. how much oil are you losing?

[CUZ'n]

Originally posted by EvilJester400EX
The smoke isn't rolling out, it's just like little puffs.

soundn lik slappys van.

[speedy]

i would try changing the kind of oil you use first off. if that does not do anything, it is probally your rings or valve seals like mentioned previously. how much oil are you losing?

Ever time I go riding after i get done the dip stick shows almost empty and i just put some in it befor i left.

Do you think it could be my piston or sleeve walls?

when i first start my ex up smoke rolls out...but then once it gets warmed up it stops..my friend told me it was my valves, they jut need re-seated...is this true? and if so is it a problem?

[EvilJester400EX]

I talked to a mechanic about the problem, he said it's nothing to worry about. It is either the valve seats or the rings, but he said when I start losing compression that I should go in there and check it out, but for now, it isn't hurting the bike. He told me most people don't even run the oil rings in mx bikes.

[AndrewRRR]

I'd do a compression check. If it's low, it's probably your rings. If it's alright then you are proabably pulling oil past the valve seals.
Either way it's not good. You aren't going to blow up your engine if you keep the oil level up but it still sucks. Now would be a good time to go for that high compression piston and cam upgrade!
For reference:
Blue smoke= oil
black smoke= mixture (rich)
white smoke= water (coolant)

[luvmyex]

Originally posted by AndrewRRR
I'd do a compression check. If it's low, it's probably your rings. If it's alright then you are proabably pulling oil past the valve seals.
Either way it's not good. You aren't going to blow up your engine if you keep the oil level up but it still sucks. Now would be a good time to go for that high compression piston and cam upgrade!
For reference:
Blue smoke= oil
black smoke= mixture (rich)
white smoke= water (coolant)
that answers my ? just put a new motor in(new to me) and im getting black smoke when i blip the throttle.but its only run 5 mins top,to check the oil

[EXtreme]

I noticed mine blowing blue smoke yesterday when I reved the engine also. What should be the compression for stock 03 400EX
Thanx:confused:

[nky400]

My friend's brand new 03 400ex puffs blue smoke too. The dealer said that it was the packing in the muffler that had come loose and was beginning to burn. They said not to worry about it. I have never heard of this happening though.

[luvmyex]

if its black smoke do i nedd to rejet or adjust the air screw? I have a 39 fcr btw

[skidplate]

Look like de 400ex like to puff the blue smoke mon !
I say run dem like scolded dogs and drop a kit in them when
she really get to smoking. That's what me going to do mon !
Peace

[EXtreme]

Originally posted by nky400
My friend's brand new 03 400ex puffs blue smoke too. The dealer said that it was the packing in the muffler that had come loose and was beginning to burn. They said not to worry about it. I have never heard of this happening though.


I know its not thje packing, I have full Graydon exhaust

Originally posted by skidplate
Look like de 400ex like to puff the blue smoke mon !
I say run dem like scolded dogs and drop a kit in them when
she really get to smoking. That's what me going to do mon !
Peace

do we have a jamican salpnutz here?????

[skidplate]

you got chalk full of nuts mon, who be this one slapnutz mon.
Everything irey ! Tomorrow we find what Honda been hiding !
JB

ill kikk u in the dirt piles skid plate. u better have ur pecker skid plate on.