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Discussion Starter · #1 ·
Yea. Yet another smoking problem, probably just pissed most of you off just by the title seeing how there's so many different posts stating similar probllems. Well I want my own.

01 400 ex 440 kit unknown brand believed to be wisco. Unsure! K&n air filter boot and box seem to be stock. Lrd pro 4 series pipe&muffler. Any internal mods are unknown untill teardown.

Starts easy Cold or hot. Jetting seems good. When cold backfire threw carb every 4-8 secs and stalls (not worried about it)
Lots of power and torque none lost as previous owner said. I've owned for a month. Previous owner put 30 hours sence rebuild in 2012. Started smoking in summer 2014 Sat for the winter. And here I am being its New owner. Gor it for 600$ good deal so I say. I bought it knowing it smoked. Previous have limited detail and info on parts ect installed.

So.. I'm left with a 440 ex that smokes a good amount. Exspecially after 5-40 synthetic oil change 3 weeks ago. Still a bit cold in new Hampshire. Considering I didn't know how,temperamental these 440s are to heat. Switched to rotella15-40 still smoking a lot none consistent but at times huge billows of smoke behind. Yes blue smoke at times blue white smoke from my understanding that's just burning a lot of oil.

My question is. Can valve seals cause this much smoke. Is it a combination.

The last 5 hours on this quad has been lower rpm riding. With occasional 1-4 sec w.o.t could I have lots of built up oil that causes it to smoke more. I also have a few drips of carboned up oil drips that had seeped from header head bolt area, don't believe it's head gasket. Any input,will help I'd love to learn more about this bike so I can start doing the work myself instead of shipping off to some shop. Thank you

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In my experience (I've worked on motorcycle engines for over 40 years); so many reasons for burning oil - specific problems for specific engines.

In general - if an engine is burning oil due to valve seals - if the intake seals are bad, the engine smokes worse on start-up, smokes less when warm and tends to foul the spark plug (plug will be wet when removed after engine quits running due to plug fouling) - if the exhaust valve seals are bad, engine smokes worse as the engine heats up, exhaust runs wet and spark plug looks normal when removed. If oil consumption changes with a change in oil type or viscosity (synthetic oils are slicker than mineral oils and gets past the rings easier) then it is possible the oil ring can be bad while the compression rings are good. In fact, and engine that burns oil typically has better compression than it had when it did not burn oil.

If an oil ring is bad but the compression rings are good, it might be caused by a failure to change oil frequently enough. K&N filters may flow more air, but they also flow more dirt. Engines run with a K&N filter that is not serviced properly (and few are) wear the rings out prematurely and can suffer other wear that might require complete rebuilding.

If the 440 kit was installed by simply boring the cylinder (Wiseco specifies having a heavy sleeve installed for installation of the kit), the sleeve might have cracked or simply distorted and the cylinder may need re-sleeving or replacement.

If the engine was worked on after the 440 kit was installed and the mechanic did not realize it needed a special head gasket (I have seen this), the gasket can get pinched between the piston and the head causing the head to loosen and it can draw oil from the cam chain well or an oil passage.

At any rate - to correct the oil burning - the engine needs to be rebuilt.
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