Bonneville America Forums Forums Technical Forums General Tech Won't stop burning oil.

I tried to "Re-break in" (deglaze) the top end running about 1000 miles using dino oil and hard riding, but the problem still persists. I got my hands on the factory service manual and found something interesting. Our bikes have an internal oil pressure release valve. I'm wondering if mine is failing and causing excess oil to be forced through my case breather tube and into my airbox. I wonder, because there always seems to be oil seeping around the tube, and the last time I had my air filter out I could feel a good amount of oil residue where the breather line comes in. Any ideas guys?

I'd be interested in other opinions as well. After my engine casing was replaced (idler shaft failure), I had an oil usage problem. The newer casings have a different breather set up than the older ones. I've found if I run the oil level near the top level line, I get blowback of oil into the airbox and find it in the plugged drain hose (usually right side). But, if I run the oil level at the bottom level line, this is greatly reduced or almost non-existent.

I made one other change. After my casing was replaced my breather hose had a slight drop as they used the original hose. I cut and slightly shortened the hose at the top to be sure that oil drains back into the crankcase. If you have a dip below where it goes into the crankcase, misted oil can collect and eventually blowback into the airbox like a burp. Newer models should not have this problem, but you should check the hose to be sure.

Besides that, I do feel some oil is leaking into my right cylinder. I suspect a valve guide seal that could be leaking. So, I actually had two problems. Triumph suggested running the oil at the bottom line on the level guage and I decided to alter the hose. Since doing that, the oil usage has been significantly less. I'll wait until there's a reason to get into the engine to check the valve guide seal.

Bob (V150super), there is something else to check. Because you probably have the original casing, there is a rotary breather that has been known to fail in the oil breather system. The later casings use a different system and do not have the rotary breather. I would take it to a Triumph service dealer and tell them you may have a rotary breather problem. This is an easy replacement and not expensive.