400ex blowing oil out the exhaust.

[whitt304]

So I finally got my four wheeler running after installing a 440 big bore kit in it. I put the kit in because it was smoking and blowing oil out the exhaust, so I thought the rings were shot. Although now that it is back and running it seems to smoke and blow more oil than before. When I had it apart I checked the valve guides, replaced the valve seals and inspected the valves themselves and all looked OK. Could the head be cracked or is there something else that can be causing this? After just 5 minutes or so of easy riding the exhaust was covered in oil and left a small puddle of oil on the ground out of the muffler that's how bad it was.

[BenHonda400ex]

Hmmm, are you sure it's oil. Mine leaked liquid out of the exhaust and at first I thought it was oil but it was just water that had got in the exhaust and had leaked from the header pipe and the silencer. I don't know what could really cause that. I'm subcribing to see what CJM says

[CJM]

Make sure its oil, not carbon build up or water condensation.

Did you store the quad upright or transport it upright for a period of time then crank it over pretty quick without letting it it seep back down.

My guess is a few different things:

1. If the oils over filled it will crank back out into the air box or thru the crankcase vent and into the exhaust depending on how it goes, once the pressure gets to high

2. Even tho you put new rings in the cylinder might be out of round and oil might be passing thru b/c the cylinder is out of round or the walls of the cyl are gouged/scratched up.

Thats about all that can happen really.

Do a compression test, it can tell you if the rings are bad. Build the pressure up when checking the compression, leave the killswitch off, crank the engine over for 5-7 secs. Should be at least 100psi, leave it sit with whatever it reads and see what happens-it drops thats bad.

[whitt304]

The piston, rings and cylinder are brand new. I bought them as a kit. Yes I am 100% sure it is oil, its never been stood upright since I put it together. And It is not overfull of oil either unless the dipstick is wrong. This has me stumped. I will take it apart again to inspect the head closer when I am a bit less P Oed at it. But if anyone has any thoughts please let me know. Thank you.

[CJM]

Are you sure the rings are on correctly, 180 degrees of each other?

It could be excess oil burning up from when you assembled it-but that usually cures rather quick.

How did you break it in? If you didnt run it with a good load on the engine you might as well toss the rings and hone the cylinder again cause they didnt seat good.

[honda400ex2003]

heres my guess...

you got the kit on ebay as a piston and cylinder with some gaskets.

the cylinder was not bored for your exact piston and it has some serious blow by because your piston isnt fitting just right.

do a compression test on it and see how it is.

just a theory, its probably wrong.

next...

i would def do a comp test no matter what, this would indicate if your rings are truly messed up or not.

it is hard to believe that it would even run with enough oil in the exhaust to drip out the end... it would be filling most of the combustion chamber with oil and pushing it out the valves to get that much oil out in a short 10 minute period.

was there any smoke at all or just oil?

just a couple thoughts... i figured i would see came about with it before i responded to it this evening.

steve

[tri5ron]

Originally posted by honda400ex2003
heres my guess...

you got the kit on ebay as a piston and cylinder with some gaskets.

the cylinder was not bored for your exact piston and it has some serious blow by because your piston isnt fitting just right.

do a compression test on it and see how it is.

just a theory, its probably wrong.

next...

i would def do a comp test no matter what, this would indicate if your rings are truly messed up or not.

it is hard to believe that it would even run with enough oil in the exhaust to drip out the end... it would be filling most of the combustion chamber with oil and pushing it out the valves to get that much oil out in a short 10 minute period.

was there any smoke at all or just oil?

just a couple thoughts... i figured i would see came about with it before i responded to it this evening.

steve I'll 2nd that guess, and add a little to it.
I'm guessing that you didn't have the cylinder measured for actual size as well as out of round. And did you verify that it was, in fact, a 440 piston? might it be possible that it is a 426? did you measure it ? if so, What did it measure out to ?

Also, another guess is, that you never took out the old muffler packing,
(I'm assuming you are not running a stock muffler on a 440),
and I'm guessing that the old packing had alot of residual oil in it from Before, you did the new Cyl/Piston.

So the questions that need an answer are,...
Where did you get the piston/cylinder from?
What brand are they?
Did you have them measured ?
Did you have it honed to insure it is round?
Are the rings in correctly?
Is the old soaked packing still in the muffler?
Who checked the head?, and how closely was it checked?

[NMills]

Originally posted by whitt304
The piston, rings and cylinder are brand new. I bought them as a kit. Yes I am 100% sure it is oil, its never been stood upright since I put it together. And It is not overfull of oil either unless the dipstick is wrong. This has me stumped. I will take it apart again to inspect the head closer when I am a bit less P Oed at it. But if anyone has any thoughts please let me know. Thank you.

Brand new does not mean it's 100% perfect... new stuff comes broken... Is the dipstick wrong? are you checking the oil properly?? do not take it apart yet... do the compression test before... that way you can start your diagnosing... might save you some headaches later...

[BenHonda400ex]

Maybe like someone said the rings got burned up because they where junk or the piston wasn't the right size. I don't buy anything from Ebay, if that's where you order stuff from. RM FOR LIFE!!

[NMills]

boy... i gotta catch up on my internet language skills... RM??? if you had a u in there it'd be RUM... but i don't think the U was left out on accident...

[honda400ex2003]

Rocky Mountain atv for parts :D

steve

[BenHonda400ex]

Haha, yeah. They treat people right! Ebay is great but sometime's it's kinda skethy.

[honda400ex2003]

there and dennis kirk, i live a few hours from there so i get my stuff over night for free if i order 100 bucks or more. :D

steve

[tri5ron]

RM I got, but Skethy ??? Was that supposed to be Sketchy ? Scary ? Skinny ? Schennectity ?
I'm lost too, :D

[NMills]

I like RM.... it's cheaper then the dealer in most cases... and i get it just as quick as the dealer get em adn i don't have to waste my time or gas goin to the dealer... Awesome store...

[BenHonda400ex]

Originally posted by tri5ron
RM I got, but Skethy ??? Was that supposed to be Sketchy ? Scary ? Skinny ? Schennectity ?
I'm lost too, :D Haha Yes Sketchy not that good of a speller. :eek:

[400ex_alldayy]

you said the exhaust was covered in oil? did u put the lilttle cover back on the cam chain tensioner? cuz that will piss oil out when there is load on the motor
just a thought

[HondaRacing83]

haha i know first hand if a 2 stroke is runnin rich itll piss oil out the exhaust. but this isnt a 2 stroke. did some oil maybe get in your gas by chance? the smoking is prob from carbon build up. mine did it, now its fine. id like to say that its condensation but you said your sure its oil. will you go taste it please? :D

[ridehonda400ex]

check your exhaust packing also, if it burnt oil before then your packing is probably covered in oil too, not mention, there was probably some in the header and you used oil during the rebuild on cylinder walls and such(i hope) so give it time and it might clear up.