In the previous episode of this on-going GS saga, I replaced all gaskets and o-rings in an attempt to stop my bike from eating oil. 1.3ml per mile to be exact. Veterans out here suggested bad control rings, allowing oil to enter the cylinder. However, last weekend I rode with a group of guys for four hours and we talked during lunch. I asked them if they saw or smelled any blue smoke at any point during the ride, answer was no. Also, compression tests for both barrels passes, barely, but its in there. So, I'm beginning to doubt this theory. I thought bad valve seals would produce blue smoke too. I see no leaks beneath, when parked or moving, and nothing splattered inside the fairings. Where is the oil ending up?
If your compression test barely passed, my hypothesis would be that the rings are in fact failing, or at least excessively worn, and some amount of oil is getting past them. Not enough to discolor your exhaust, but enough to lower the oil level over time.
1.3L/1Kmi oil consumption, if burning it, will not be enough to show in the exhaust noticeably IME.
In fact for a time Audi claimed that '09+ A4/A5/Q5 which burned 2-3x this amount when BRAND NEW were in the range of normal and their official solution to owners of these cars was to offer, for free, to top up the owner's oil if they stopped by the Audi dealer, at least during the 36K warranty. How nice. Anyway...
My Miata had a bad oil control ring (stuck in the groove) and I couldn't detect any smoke until it was over 1 quart per 500 miles. In truth I thought it was leaking.
Compression test will not give you much indication of oil control rings condition.
Anyway, I'd say you're burning the oil, and that doesn't really sound excessive. If you have slightly low compression then that would explain it.
Remember.......this engine is dated and air cooled. If you are giving it a hard time for several hours at a time its more than likely evaporating, particularly if its a cheap mineral oil in there.
Yeah it may have a cooler, but its not under the piston crown where things are hottest.
Plenty on the net about volatility and evaporation rates. Most of it from manufacturers making inflated claims over their products while putting down products from rivals but there is some truth in it. Some oils will evaporate at a higher rate than others.
Interesting--I never thought about oil evaporation.
Quote from: mr72 on July 05, 2017, 09:24:21 AM
Anyway, I'd say you're burning the oil, and that doesn't really sound excessive. If you have slightly low compression then that would explain it.
This is great news. I thought the engine was on its way out. Thanks dude