Burning oil?

[Snoman6115]

I changed the oil/filter in late july and went for a trip wed. and was almost a quart low on oil. there are no spots on the ground where i park it and no signs of it leaking but im losing oil magically, anyone else have this problem? is it just because of it being air cooled and running hot?

 

[drewpy]

they do burn a bit of oil, depends how worn the engine is!

 

[Snoman6115]

so basicaly to stop it i would have to do a complete rebuild? hmm maybe i need to save over winter for a new bike seems like less hassle lol

 

[drewpy]

maybe just worn valve seals.

Don't be defeatist life's a bitch sometimes but you gotta grab it by the balls and give them a tug

 

[HoughMade]

How long was the trip? Does your bike have a dipstick or a sight glass? Did you check it on the center stand, or side stand?

 

[Snoman6115]

well ive only put on about 700 miles since the oil change mostly around town 2 220mi trips, i always check it center stand with dipstick.

 

[XSLeo]

Do you try to keep the oil right up to the top line on the dip stick? If so that may be why your using oil. Try running it half way beteen the upper and lower lines.
If over filled it will blow off the extra out the crankcase breather.
Leo

 

[HoughMade]

I concur with that suggestion, but keep in mind that this is a 30+ year old bike. 1 quart every 500 miles wouldn't bother me if it was not visibly leaking or smoking. I usually check about as often as I fill the gas tank and sometimes have to add a bit. That would not cause me to tear down.

In the '90s and before, a brand new car that used a quart every 1000 miles was considered normal.

 

[Lou Ranger]

My engine is different, but I couldn't believe how much oil was in the filter compartment when I changed the filter for the first time.
Did you check the oil after you had run it for several minutes after changing? When I did that on the dohc, it needed another half litre to get it to the top mark after I had put in the measured amount which the book called for.

A question for the others - is it possible that 30+ year old oil specs were different from what is now on the market? The manual called for SAE 20W-40 SE or SF. I haven't seen 20w-40 oil for years. Could a 10W oil seep into places Yamaha didn't intend and then burn up on starting and running?
Now one can get 10-40 or 20-50. Don't know about SE and SF as I just buy the stuff that says for 4 stroke M-Cs with wet clutches.

 

[xschris]

Do you try to keep the oil right up to the top line on the dip stick? If so that may be why your using oil. Try running it half way beteen the upper and lower lines.
If over filled it will blow off the extra out the crankcase breather.
Leo

I would keep it full The xs400 is NOT like the xs650 that tends to blow a lot of oil out of its breather tube

 

[226dark]

so basicaly to stop it i would have to do a complete rebuild? hmm maybe i need to save over winter for a new bike seems like less hassle lol

What Drewpy says. Valve seals aren't a major deal. Oil could be getting past rings, check compression. Could be bad o-ring between piston barrels and head, if you clean the engine do you see any sign of any oil (not dripping wet) anywhere around the head gasket?
Welcome to the joy of motorcycling, an older bike needs some love and it will return the love in proportion. If you don't have a love for the end result of working on it -riding - get a brand new warrantied bike or maybe riding just isn't worth it. Get another used one and then wait for the first thing to go wrong on the way home after buying it, and then leave it on the shoulder and forget about it.
Oil from breather tube you would see a mess! With that much.
No, not because air cooled and getting hot.