Where's my oil?

Fred T

Mi. Trail Riders
Joined
Mar 23, 2001
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#1
I've always dumped in a whole quart of tranny oil when I change it. (I change it every 2 rides) and the last 2 times I decided to measure what I got out of it when it drains and it's slightly less than a full quart, like 80% -both times. Soooo where does that oil go?

I know the tranny has a vent tube but it's routed upward into the airbox and I dont' see oil leakage in there.

My engine is sound and I know it's not burning any of the tranny oil through bad seals, it's new with about 650 miles on it.

I assume this is normal but it made me curious.

Fred
 
Joined
Jan 25, 2001
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#2
Well sorry dude it don’t evaporate. If the level is going down then it is leaking out the seals or the crankcase joins.

Maybe that the gear shaft or output shaft is weeping & you don’t see it behind the sprocket say? The vent will only leak if you leave your bike upside down for a while, which isn’t out of the question if you ride like me.

A leakdown test will tell you if the bottom end has a secret arrangement with the gearbox. Not every shop (or many) has one so you may have to build your own.

Check out the macdizzy site for DIY guide if you want to build one.
 

Fred T

Mi. Trail Riders
Joined
Mar 23, 2001
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#3
Isn't it possible that there is a small amount of oil that won't come out because it's clinging to the insides of the cases, clutch and tranny gears?

Have you ever measured what you take out? Do you get a full quart?
 

MADisher

Grand Data Poohbah
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Apr 30, 2000
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#4
I thought, and someone correct me if I'm wrong, that if you use a full quart, your gonna lose some through a breather somewhere as it's not really ment to hold a full quart.

Also, my service manual calls for 800ml if dry, but for a change only 700ml as they are sure you won't get it all out.

Just another perspective.

I use a full quart of the Spectro 80wt because I can't stand the rattle, I don't think I ever really get a full quart back. I've always assumed (a) some's coming out the breather tube somewhere and (b) my bike spends a fair amount of time on surfaces other than the wheels.

I'm pretty sure I don't have any known leaks, I just chalk it up to attrition. Now my zuki, still, after replacing all the seals, weeps from the shifter lever a bit.

-MD
 

Canadian Dave

Super Power AssClown
Joined
Apr 28, 1999
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#5
I think Fred T has hit the nail on the head here. Not all the oil originally added to the transmission is going to drain. There is going to be oil that clings to parts with in the transmission that is going to be left behind during a typical oil change. If you don't feel there is any reason to be concerned you're looking oil through a bad seal I wouldn't get worked up about it. Ride and enjoy.

David