Rings, Valves, or Carb?

[RNCC400EX]

Here's a very crappy video of the smoke my quad is putting out. When I had it tore down the rings/cylinder looked excellent, don't see how they'd be leaking, but I could always be wrong.

The motor was semi-warm when I shot this. Just uploaded the video might take a few minutes to process.

http://www.youtube.com/watch?v=hCi5m8h5t0I

[k4f5x0r]

best bet will be to ride it around for a while. then check the oil. if any ismissing then your valve seals are most likely messed up. if its not loosing oil. drop down your main some or move it up on the clip.

[Snipe]

Un burnt gas smoke is black that is white or blueish that is im putting my money on burnt oil.

[honda400ex2003]

If it burns oil at startup and on hard acceleration it is valve seals. If it is burning oil all the time and when it is warmed up, it is the rings. If it is blue smoke it is oil, black is rich. take a look and smell it. There is a distinct smell to oil. the black will be the carb being jetted incorrectly. Otherwise the rings or the seals or bad depending. The video looks like it is the rings but when it is revved up. you would just see a puff under hard accel during a ride. If you let it sit over night and go to start it up and it is really smoking bad compared to the rest of the time it is the seals. I guess it could be a combo of both at different times. Good luck, steve

[RNCC400EX]

Unsure if it makes any difference, but I was sitting still the other day, waiting on my brother to catch up, and the smell from the smoke was enough to burn my nose and throat. I've worked around MANY running engines and NEVER experienced anything like that. I run 93 octane, no additives, so what the hell could that have been?

Also, the majority of the smoke on hard acceleration is black, so I'm guessing I need to check the jets on this thing. We got it from some kid in Delaware, and we live 1000 FT + up in the PA mountains. I know elevation has a lot to do with jetting, but where can I find a happy median when we go from 1k to 1.75k while riding?

[honda400ex2003]

It is most likely oil burning then. It looked pretty blue anyway from the vid. steve

[monkeyballs]

HOLY CRAP! SMOKIN! First of all, what are you running for jets.

Then, you said the piston and rings looked good..... How did you determin this. Did you take a telescopic T gauge and messure it or a cylinder boar gaguge.. Or did you just say ohh.. that looks good.. And did you mesure at the 3 diffrent positons? Did you have the top end off?

Then where did you place your ring end gaps? Not close together right?

What year is it? And have you ever changed your valve guide seals? Becaus im sure the seals are playing a small role in this.. If its an older.. But I highly doubte they will make it burn that much oil. I would not doubte it if you have to go to a 440 or re plate. And you said that you went for a small spin to warm it up a tad.. Looked like it had a hard time starting. Incorect jetting? Low compression?

FINALLY! If you want reassurance about the burning oil just check your spark plug if its black and chippy. Your burning oil... But I gaurantee you that you are burning oil.

[RNCC400EX]

I have no clue as to what jets are bring used, I didn't put this things together.

Not long after I got it the cam chain tensioner ended up going. Being unfamiliar with ATV engines, I took the head and cylinder completely off. No I did not check anything with a micrometer. I checked the cylinder for scarring or a ridge, which there was none. Cylinder looked like it had a fresh hone to it. It hadn't been long since the 426 kit was installed, but even then I don't know if he just got a sleeve or the whole cylinder, not that it'd matter, but I'm pretty sure he did nothing to the head. I was sure to place the endgaps at least 120 degrees out from each other when reassembling, and yes I used fresh gaskets.

Guess my best bet would be to throw a fresh set of rings, valves, and valve seals on it anyways. Have some downtime due to bearing carrier crapping out anyways.

Here starts the nickel and diming process.

[honda400ex2003]

if you take care of it all at once then it will not start to nickel and dime you. spend the money at once and do it right and you can have many many years of fun with good maintainance and such. Making sure you change the poil, keep the valves adjusted and keep the filter clean and it will run good for a long time. change the seals, rings, get it honed for the rings to seat right, get a new cam chain, check out the tensioner and guides to make sure they are in good order, and get the valves lapped to get them to seal perfect again and you will be good for the motor. put some new bearings in the carrier, oil it all up good, check the tierod ends for play, the wheel bearings, swingarm bolt and bearings, and you will be sitting in tall cotton. steve