How does oil get in the cylinder

kevbo82 · Jun 3, 2013

Besides bad rings and/or valve seals, are there any other ways oil can get in the cylinders? valve adjustment, oil level, etc?

ILLF8ED · Jun 3, 2013

Porous head casting, cracked cylinder come to mind.

Hobot · Jun 3, 2013

Ugh, blow by-suckion around the push rod tunnels and the oil drain hole partially occulded.

pete.v · Jun 3, 2013

A failing head gasket. You may not see anything blowing out but that doesn't that it isn't sucking in.

79x100 · Jun 3, 2013

Down the outside of the guides is possible if they're loose in the head.

If you have the standard air box / breather set-up, it's quite possible for an overfilled oil tank to pour oil into the air box . Certainly with the Mk2A / Mk3 type, this will allow it to be drawn into the cylinder. With the paper filter, it will usually drip out first.

Rohan · Jun 3, 2013

79x100 said:
Down the outside of the guides is possible if they're loose in the head.

+1 on down the outside of the guides.
Sign of the head not being heated when the guides were removed/installed.
Big problem in the engine reconditioning world generally.

850's breathed into the airbox - oil mist etc.
If this beathing is excessive, the smoke out of the peashooters will remind you of it.

kevbo82 · Jun 3, 2013

i have a small amount of smoke from the pipes at idle (gotta get your eye at the right angle to see it) but then when i blip the throttle i get puffs out of both sides. the bike is going to go to the shop that rebuilt the motor soon to have this checked out, but i just keep trying to check things out on my own in the meantime. any warning signs or things to look for when it comes to head gasket problems?

Rohan · Jun 3, 2013

The head needs to be retorqued, 2 or 3 times even, after a new head gasket.