I have a 1980 naked GL1100 that I have been working on since 2006. this last piece is a mystery to me and no one I have asked can offer an explanation.
My bike eats up a quart of oil every 100 miles. the mystery part is: that it isn't smoking
There are no visible leaks where it is parked.
It runs smooth and does around 32 mpg.
The spark plugs look good and no sign of fouling.
People that ride behind me complain that it stinks. I did find some "sweating" from the bottom of both valve covers (I recently did the head job and perhaps I didn't place the valve covers well (new valve cover seals.) and I think it occasionally drips on the pipes and stinks as it is burned off by the pipe.
Any thoughts? a direction? I thought it may need rings but a friend said that if it was loosing that kind of oil it would be bellowing so much smoke that I would be pulled over in a heart beat.
Any thoughts?
:eek:

Well I'm in no way a mechanic and I'm not telling you anything you don't already know, but it seems to me that missing oil has to
1. be burned off
2. leaking out
3. mixing with something else.

It seems to me that a quart in 100 miles would be noticable somewhere, but if it's droping down onto a hot surface it would evaporate quickly, but you would have a smell lingering on the hot surface. If it's mixing with water then it would show up on in the radiator. You say you don't see smoke out the exhaust but you might try placing an old teeshirt about 6 inches from the exhaust and reving up the engine and see if you get any oil splater out the pipe.

Other than those things I don't have a clue. Unless someone is stealing oil from your bike at night. (LOL) Good luck, I hope you find the problem and can get out and ride.

Do you park on the side stand overnight? If oil is dripping on your exaust you could, over time, see a deposit ov oil there.

... Howdy ... Zen ... My Guess Is A Leak ... If It Was Internal The Engine Would Run Bad And You Would Have Fouled Plugs ... Lay Down And Start Looking At The Frame For Any Hidden Deposits Or Splatter ... Thats A Lot Of Oil To Be Burning On The Pipes Without Showing Up Or Having Drips ... Valve Covers ... Also Check Around The Oil Filter ... Happy Trails ...

Thank you for the replies. the consensus appears to be towards a leak that evaporates. I will degrease/pressure wash the bottom of the bike after refitting the leaking valve covers and put a clean cardboard under the bike after that and see if I can catch the oil stealer.

Just a shot in the dark..Are you sure you have the correct oil dip stick? If not, it may look like you're down when you really aren't....Like I said....just a shot....:D

1000 & 1100 wings have a sight glass, no dip stick. if the oil filter housing is over tightened it will compress the o-ring and you will get a leak