Need some advise smoking 400ex

[atvmbaca]

Need some advise, my 400 is pretty much stock except for a yoshi
slip on, and I noticed every time I start it up it blows white smoke
out for just about 30 sec as you rev it up then, I never see it again, any thoughts on this I know my jetting is good and also I did a compression test on it and it was good according to the spec limits given for it, could it be leaky valves, its only about a 1 year old
I hope this is not something major because it runs realy strong.

How much and how long does it smoke? does the color change or is it just white?

Sounds like it could be leaky valve seals but with it being only a year old seems a little quick for them to go bad.

[hondaboy400ex]

ya i have the same problem and im all stock for the motor at lest

[atvmbaca]

It smokes for about 15 to 20 seconds mostly white with maybe some black but not much should I be realy concerend will this,will this hurt my performance, it seems to run really good right know and I check the oil all the time seems to be ok, those who have this problem let me know what you did or think I should do, Like I said its only a year old and I dont run it that hard I believe it also might be a leaky valve will this hurt anything?????

[DGR Designs]

well black is just carbon build up. don't worry about it. white is probley nothin to worry about either as its probley the time it takes for your oil to run all throught your engine and up around the seals. not a big problem. also its common for your engine to make a ticking noise during this period. don't worry about it.
~Dave

[atvmbaca]

Thanks Bro!!!

[Pvt. Maggot]

your quad has a bad habit :huh mine does it too...i'm pretty sure its just while its warming up

[atvmbaca]

So should I be very worried about this or not!!!!

[UglyMotha™]

white is usually condensation probably in the exhaust now mine on the other hand is only a year old and when i fire it up it blows blue smoke for about 30 secs and now that i got it ripped apart it it's got oil running down into the left exhaust port when it sits so i'm assuming my seal is bad on that side already valves still seat real good though

[RAPTORAZ]

Is it consuming oil?

[ridesa02400EX]

mine has been doing the same thing it just smokes a little blue until it warms up is it valve seals? i blew it up and just had it rebuilt but the shop was really stupid and i dont think they replaced the valve seals

[UglyMotha™]

Originally posted by ridesa02400EX
mine has been doing the same thing it just smokes a little blue until it warms up is it valve seals? i blew it up and just had it rebuilt but the shop was really stupid and i dont think they replaced the valve seals

it's either that or the valve guides i took a flashlight and looked up the exhaust ports and you can see after it sat overnight the oil running down the shaft of the valve it's nothing major just a little bit and then when you fire it up it burns off causes a little smoke and then it's fine the rest of the day until it sits overnight again

[atvmbaca]

thanks to all of you who gave me feed back on this problem.

[ridesa02400EX]

alright ill just check it out tomorrow

[RED121572]

White smoke is condensation. Dark smoke is oil.

[UglyMotha™]

Originally posted by RED121572
White smoke is condensation. Dark smoke is oil.

define dark because black is a rich fuel condition where as blue is a burning oil problem

[RED121572]

Good call bud, I shouldve been more precise in my reply. Burning oil is kinda blue. I use Castrol Synethic oil. It smells really funky when it comes out the exhaust.:D

[atvmbaca]

An earler post asked If my bike was consuming oil and I have checked it and it seems like it is but not to much is this bad,like I said it runs real good right know, will this cause more damage latter on!!

[atvmbaca]

An earler post asked If my bike was consuming oil and I have checked it and it seems like it is but not to much is this bad,like I said it runs real good right know, will this cause more damage latter on, I just dont fell like taking the motor apart to fix a possible valve leak.

[RED121572]

I know bud, Im in the same boat right now that you are. Its a bummer. :( Leaking valve seals prob would "clog" up the combustion chamber over time. It would leave an ungodly amount of soot in there. For that, Im fixing mine before taking it out again.

Good luck with it.

[quadman21]

The smoking issue is always frustrating. In fact I've gone through this many times and it makes me paranoid to see even a little puff. It could be any of all the above the reasons people stated. But aer't you guys having an unusually cold winter there in arizona? It's real cold here in VA and my quad does the same thing. But I know I'm running rich. Plus with it being cold and having condensation in the pipe when it sits over night, it's kinda nature of the beast. I wouldn't worry too much but definitely look into to be sure.

[RED121572]

Hey quadman, good point.:)

[atvmbaca]

thanks