Diagnosing Smoking...

[thisperishedmin]

Alright...I know I had a thread going before...but I ended up parking her over winter - and now I'd like to get things straightened out for sure.

In short, my quad (416 overbore...unsure of hours on the motor) is burning oil. I've ruled out condensation in the exhaust - but still cannot decide if the smoking is coming from valves or rings. It definitely smells like burning oil too - has a very white color - I couldnt say it has a blueish tint, but someone else may think it does...sadly i dont have a pic / video.

Anyway, it smokes on startup and idle, and if you crack the throttle from idle it smokes a huge puff. When riding at a constant speed or when the throttle is held at a constant point, 1/2 to 3/4 throttle it seems to smoke less. When riding, it seems almost nonexistant...however - that may just be an effect of moving and dissapating through more air.

Basically, short of a leakdown - is there any other good way to determine seals vs rings. Or - from others experience, should I just save the $150 for a top end kit and the seals and do it all at once and be done with it?

Anyone know of a good / cheap place to order top end kits for a 416? And lastly - if it needs new valve seals - do I need to get any valve guides or anything else besides the seal?

Thanks in advance...cant wait to get her back to perfect health :D

[CSR400EX]

sounds like valve seals. but it could be rings. only way to see if its rings is a leak down test like you said. id replace the valve seals while i was at it too.

[cbrooks118]

I would put my money on rings, but would just drop 150-200 and replace it all. RockyMountain sells wiseco's pretty cheap

[limetimeracerII]

It might be something else. My bike does the exact same thing. I've done some checking around and it seems like more than a few people have this problem. Another possibility could be that when the motor is shut off that oil could be leaking in between the valve guide and the head. I know it sounds weird but it makes sense, I've checked every other possibility on mine and figure this is the only thing it could be. I know for a fact that it has happen on other bikes. One fix is to take the valve springs off and the washer that they sit on off and clean the head real good. Pour some yamabond around the guide, let it set up then reassemble that might take care of it.