1St Gen - That pesky tiny oil leak

Well spent more time under the scoot looking with the blacklight. Nothing in the normal areas.

Another drop seen on the bottom of the rubber dust cover over the u-joint. Looking more carefully, it "could" be the oil seal just before the u-joint. Part #18 (93101-35085-00) on parts page D1 (37 or 112)

Follow my thinking...if the oil drips out of that seal, it will run out the dust cover and drip onto the frame rail. It will flow back to the left exhaust pipe and onto the left saddlebag...which does get oil on it during a run. At rest, it will run down the left side rail to the lowest point...which is forward... under the area where the neutral switch/stator wires/shift shaft are.

My only problem with this argument, is you would also think the oil would run out the back of the dust cover and to the rear... along the swing arm that encloses the drive shaft. But it's dry as a bone! So more confusion...I don't see how it could leak without blowing oil back along the swing arm/drive shaft side.

The area of normal contention, neutral switch/stator wires is dry except for one engine bolt that faces into the block from left to right. It has a drop of oil on the bottom of the head. It's tight so I can't think of why that would leak. Don't want to crank down on it since I can't find it on the parts pdf...

No cracks. No obvious issues other than the leak...which is slightly worse now than 2 weeks ago. 3 drops instead of 1 small one.

Guess I'll just keep on riding and watch the oil level. Something is bound to show up at some point that makes sense....

I checked the service manual for Middle Gear Service on pages 3-45 & 54 and they call that seal a dust seal but I do see where the parts fiche calls it a oil seal. There is a O-ring in the manual and parts fiche, #19 in the fiche that could be the issue. Looking at the pictures in the service manual and from what I remember, this seal isnt accessible from the back of the engine without taking out the middle drive shaft and housing with the shims. If you want to make sure if isnt in that area, you could remove the rear wheel, swing arm and then you would have access to it. My thought if is was leaking oil the swing arm boot would have the oil in there and not on the swing arm. This would show as a leak at the back of the engine.

Just some of my thought.

Keep up the good work.

Rick F.

On 4/23/2018 at 4:39 AM, videoarizona said:

Well spent more time under the scoot looking with the blacklight. Nothing in the normal areas.

 

Another drop seen on the bottom of the rubber dust cover over the u-joint. Looking more carefully, it "could" be the oil seal just before the u-joint. Part #18 (93101-35085-00) on parts page D1 (37 or 112)

 

 

 

 

Follow my thinking...if the oil drips out of that seal, it will run out the dust cover and drip onto the frame rail. It will flow back to the left exhaust pipe and onto the left saddlebag...which does get oil on it during a run. At rest, it will run down the left side rail to the lowest point...which is forward... under the area where the neutral switch/stator wires/shift shaft are.

 

My only problem with this argument, is you would also think the oil would run out the back of the dust cover and to the rear... along the swing arm that encloses the drive shaft. But it's dry as a bone! So more confusion...I don't see how it could leak without blowing oil back along the swing arm/drive shaft side.

 

The area of normal contention, neutral switch/stator wires is dry except for one engine bolt that faces into the block from left to right. It has a drop of oil on the bottom of the head. It's tight so I can't think of why that would leak. Don't want to crank down on it since I can't find it on the parts pdf...

 

No cracks. No obvious issues other than the leak...which is slightly worse now than 2 weeks ago. 3 drops instead of 1 small one.

 

Guess I'll just keep on riding and watch the oil level. Something is bound to show up at some point that makes sense....

So how does this oil leak story end up? Did you find the leak spot? Did u fix it?

I’ve come to terms that my tiny mystery oil leak is just part of the lure.

5 minutes ago, Pasta Burner said:

I’ve come to terms that my tiny mystery oil leak is just part of the lure.

And he replaced the Yamaha logo with a Harley one ........

15 minutes ago, saddlebum said:

And he replaced the Yamaha logo with a Harley one ........

I said TINY leak! 😸

There are two bolts in the same area that can cause the same type leak...the top bolt for the clutch slave needs to have a sealant on it when installed and the bottom bolt of the middle gear cover needs a washer.

In addition, the o ring for the clutch shaft and the rear cylinder valve cover can leak oil and appear in the same areas. 

21 hours ago, Pasta Burner said:

I said TINY leak! 😸

Oooops.....

On 8/6/2022 at 3:47 AM, Sandro17 said:

So how does this oil leak story end up? Did you find the leak spot? Did u fix it?

Nope. Never did find the leak. I did replace the shift shaft O ring and the neutral switch orange O ring... But I still got a tiny drop of oil after a day run. Gave up! Wasn't enough to bother me anymore. 

The bike ran so good.... Decided to enjoy the ride!

Sold to a friend's son. I hope he's having fun as well. It was a great bike!!

I have never been too concerned with tiny oil leaks as long as they are not wet dripping leaks. What we refer to as oil sweating or class 1 leak isn,t worth chasing, neither is a class 2 or wet but not dripping. I might think about fixing it, depending on were it is and how much work it will take to fix. A class 3 or dripping oil leak well that's a winter project. Unless it's so severe it is affecting my oil level which In most case's is unlikely.