My sp335 was blowing blue smoke out the muffler. Tore the engine down, replaced the piston, rings, and the valve seals the cylinder was in spec according to service manual. Rings were worn out. Rode the the bike 6 times after the top end rebuild. Ran about 2 tanks of gas through it, no smoke ran fine. Last weekend rode for 5 hours played in the mud, ran fine except for last hour of riding. Started to smoke again, LOTS of blue smoke, checked oil was not milky, no water in air box, did find in air box white foam coming from breather tube. Figured some water must of entered into the engine somewhere not sure where. Checked the compression was in spec accoriding to service manual. Replaced breather filter checked lines for blockage, replaced air filter. Still smoking like crazy. (I mean lots of smoke)

Any ideas?

 

Broke a ring possibly? I've done it on new car engines. Smokes like a train after that happens.

 

Not sure on your particular engine, but most cylinders need to be honed to break the rings in so they'll seal properly.

 

The bore was honed and the engine was broke in (ran 2 tanks of fuel through it). Never smoked the till last time went riding. Figured if it was a brokin ring I would of lost some compression, plus the engine starts right up and has plenty of power, just smokes alot. Unless maybe just the oil ring broke?

 

First do a compression check. If compression is ok I would look at a clogged breathing system sort of like a pcv valve on a car (if your quad has one).

 

sp335aok,

I could be in left field here because I have not had a sp335 apart so I do not know for sure what it has for rings.
But I can tell you that if the oil ring broke you could still have good compression and still smoke. I did a top end rebuild on a tractor once that the owner said his two boys rebuilt, but it smoked like a chimney ever since. The bottom end and cylinders were in perfect shape even the compression rings. But they did not put the expanders behind the oil rings like they were supposed to so the oil rings were doing nothing. I put another complete ring set in and she run perfect after that with no smoke. I'm not saying you put the oil rings together wrong but freak things do happen, so if something broke on them it could be your problem. If everthing else checks out with the airbox and oil levels and such, it may be
something to look into. Again, I have not had one apart so this is mearly a suggestion.

H.O.

 

UPDATE:

Tore engine down, found out oil ring was wornout, the top ring was still in spec. Must of got dirt into oil somehow. Checked air filter no it was sealed and no rips in it.