Oil Hemorrhage!

My 80 Yamaha Sr250 has a terrible leak at the front sproket. We were riding it around for one and a half days with no problems. Towards the end of day two, I noticed some oil. On the third day, the oil seemed to gus out, covering the wheel, sing arm, chain, etc. I took the cover off to see where it was coming from, cleaned and dryed the area and rode about a half mile. Got to our destination and found the oil leak to be from the front gear. I've noted that the sprocket has a bout 1/8" of lateral play. Cleaned it up again and pressed the sprocket towards the engine and left it for about 3 days and no drips or anything. Could this be a bad seal, chain tension, or some sort of spacer related problem?

The oil is leaking from right behind the front sproket. I've checked my manuals and it doesn't say what the sproket is connected to. Is it connected to the transmission? With a leak like this does would you suspect that I would need to replace more than just the seal?

Also, the bike was stolen from us and found dropped on its left side. This problem started after we got her back.

what kind of bike is it?I know it is no laughing matter but it appears to be a new innovation, I will split the profit, a self oiling motorcycle chain.

Might be an issue with Oil Seal 93102-25208-00 behind the sprocket.
Could check with Yamaha dealer as to availability and ease of replacement.
Some such seals are rather easy to replace once the sprocket has been removed.
But just guessing as to the bike at hand.

Good Fortune!

you say there was two of you an a 250?

donthaveakawman-it oils more than just the chain! the ground, the frame, side walls, battery box, pants, anything and everything! and yes two of us on a 250 which ends up being around ~275 lbs. we've done two on a 50cc ruckus.
ickbro.blogspot.com/2011/12/winterxgames.html

Patton-thanks you! this was an exploded view i was looking for! i kept finding a less descriptive one.

One place for parts diagrams is

Click > www.babbittsonline.com/motorcycle-parts-for-sale

Go to Parts > Yamaha > 1982 > SR250J > Transmission

A split screen should appear, with diagram on left and parts listing on right.

Oddly, the seal is number 25 on the diagram, but number 26 in the list. :huh:

Good Fortune!

candyskateboards wrote: donthaveakawman-it oils more than just the chain! the ground, the frame, side walls, battery box, pants, anything and everything! and yes two of us on a 250 which ends up being around ~275 lbs. we've done two on a 50cc ruckus.
ickbro.blogspot.com/2011/12/winterxgames.html

Patton-thanks you! this was an exploded view i was looking for! i kept finding a less descriptive one.

no wonder it blew up.

donthaveakawman wrote: what kind of bike is it?I know it is no laughing matter but it appears to be a new innovation, I will split the profit, a self oiling motorcycle chain.

My TT500 does that! It's great. It does not leak enough for me to replace the worn collar, it leaks just enough to keep my chain lubed. It's brilliant! :woohoo:


On topic: I'd make sure the seal is good, the o-ring is good and that the collar is not worn badly. Check for cracks in the case too.