I bought my Warrior used in 2006 and it has been doing this ever since. Whenever I get on it hard like climbing a hill or spinning the tires when I'm stuck (anything with high RPM's) it will start smoking from the cylinder head from accumulated oil. I'm not sure exactly if its an oil leak or if its just accumulated oil that starts burning when it gets hot. I've made an attempt to clean it all off but it continues to smoke.

It also smokes a lot when I start it up but clears up within a few minutes. I pulled the spark plug today and it was oil fouled which according to the manual means piston rings, valve guides, or improper jetting. The only mods I have (that I'm aware of) is a K&N filter with a closed airbox and a DG slip on that's a little leaky at the midpipe. I'd like to maintain some reliability with my quad so I'm hoping that you guys could help me out and point me in the right direction!

 

Sounds like you have a couple seperate problems if you have smoke coming off the head and through the exhaust.

On the head, it's probably leaking past one of the valve adjustment caps.

Through the exhaust, it's probably valve seals or maybe the piston rings. Usually when it smokes like a 2-stroke during startup but thins out or stops after warmup it's the valve seals.

 

Thanks for the info. I think you are correct on the valve cover. The exhaust valve cover is 1/2 stained with oil (the 1/2 facing the spark plug) so it is probably coming from there. Are piston rings or valve seals tough to change? Pulling the top end apart looks pretty straight forward and I'm fairly mechanically inclined.

 

Well, the oil was leaking from the intake valve cover because 1/2 the seal was missing!

As for the smoking, it didn't start until I recenlty pulled my head pipe off to knock the rust off and spray it with high temp paint. Could that have anything to do with it?

 

if you didn't seal it up properly when you put it back on, it's remotely possible that it's related, but still not likely.

Warrior engines are one of the easier 4 strokes out there to rebuild, but it's still not something that a beginner should attempt by themselves the first time around. Even though it's a fairly simple, straight-forward design, there's still a lot to go wrong if you start taking guesses or aren't paying close enough attention. Especially when you get to the valve seals.

While the top end is apart it would be best to throw a new piston in it with a slight overbore, and then of course get the cylinder bored and honed for the new piston as well. Replacing just the rings isn't going to stop the smoking completely if the piston or cylinder walls are worn or scarred, and at a minimum you have to at least take the jug off and hone it anyways or the rings will never break in and seal up properly. A good aftermarket piston kit will cost you $120-150, and will be stronger, lighter, and with higher compression than stock to bump up your performance a little. I've been in the exact same position as you, and I just threw in a wiseco high compression piston while it was apart since it's literally 5 more minutes of work to put a new piston in, and usually about $50 for a machine shop to bore and hone your cylinder.

Hope that helps

-Greg