Drive shaft leaking after replacing seal

[RempageR1]

Hi,

Over the last four years, I have had to replace the drive shaft seal twice and now it`s leaking again. I`m talking about the seal where the shaft exists the engine block, number 18 in the diagram below. Also, I`ve replaced the bearings 10 and 13, so they are fine.

I _think_ it only leaks when I run the bike hard but I can't say for sure.

Has anyone else had this issue?

Thanks!

 

[davesax36]

Has it been bent both times?

 

[one2dmax]

Might have a groved surface on the ujoint where it enters the seal?

 

[wildweasel_pt]

Or maybe leaking from the final drive instead?

 

[RempageR1]

Hi all,

Thanks for your replies!

To answer all in one:
- It wasn't bent
- It`s engine oil for sure, pumpin is still filled to the top.
- uJoint: From memory I know there was a ring visible but cannot say if it`s from that part being polished by the seal or if it`s actually a grove. I`ll check when disassembling the bike.

Thanks!

 

[wildweasel_pt]

There is a thick washer (1/4") where the fwd yoke nut seats (#15). the nut actually makes the whole assembly fit snug, both bearings and 2 spacers inbetween bearings.

 

[RempageR1]

There is a thick washer (1/4") where the fwd yoke nut seats (#15). the nut actually makes the whole assembly fit snug, both bearings and 2 spacers inbetween bearings.

Hi,

Yes, and crush washer (12) is there to take up slack and so you can set it up at the specified torque. Have done that twice (it`s good to always order two if the washers as it`s very easy to compress it too much).

Anyway, four days ago my daugher was born so currently I have little time to work on the bike, I will pick this up in a few months :eusa_dance:

 

[RempageR1]

Hi,

Today, I tore the bike apart and found out it wasn't the seal after all. One of the bolts that goes into the bousing bearing was leaking oil (lower left one). The seal itself was absolutely dry, so my conclusion about the third leak having the same cause as the previous two was a bit premature.

Thanks all for helping!

 

[RempageR1]

Well,

I tested the bike today and it was leaking again..... It`s driving me mad so here`s what I know:

- The u-joint seems try (might be because of centrifugal force)
- There`s oil on the rubber boot
- There`s oil where the pumpkin connects to the swing arm
- The oil seal where the drive shaft exits the engine is dry


Just for verification, is it even possible for oil leaking from the engine to make it all the way down the swingarm? There is a small hole at the bottom of the boot which should expell any leaked oil.... If not, I should be troubleshooting two leaks, one from the pumpkin and one from the engine....

Thanks.

 

[one2dmax]

Oil can travel up or down the arm easily.

 

[RempageR1]

Hi,

Well, I found the cause of the leak... The two bolts on the top of the crank case around the exhaust shaft were loose... I probably had not torqued them when working on the bike last winter...

My bad!

 

[CustomMax]

Which two bolts are those ? I've been dealing with the same kinda leak issue and almost ready to lose it!!! Even a hand drawn pic would help. Thanks

 

[wildweasel_pt]

Ed
He should be talking about 2 of the 3 that hold the shaft output assembly

 

[[email protected]]

My guess is he is talking about the 2 pinch bolts that hold the output shaft assembly in the block.

 

[CustomMax]

Ok, I'll check all of those and see if any are loose. Just sucks cause it's making a mess and it only happens when I'm at higher speeds on the highway. Doesn't seem to leak around town. And Thanks Fred and Mike for your Input

 

[Redbone]

Just to be clear, the bolts in question are part #21 (of which there are 3) holding down part # 17 (housing).
http://www.ronayersmotorcycles.com/...Motorcycles&make=YAMAHA&year=1992&fveh=203593

I am replacing part # 19 (o-ring) in an attempt to seal a leak from this area. What is the torque specs on these bolts?

 

[[email protected]]

Just to be clear, the bolts in question are part #21 (of which there are 3) holding down part # 17 (housing).
http://www.ronayersmotorcycles.com/...Motorcycles&make=YAMAHA&year=1992&fveh=203593

I am replacing part # 19 (o-ring) in an attempt to seal a leak from this area. What is the torque specs on these bolts?

My manual shows 30Nm/ 22 ft-lbs

 

[CustomMax]

Thanks Brian, I figured those were the ones that Fred was talking about and I'm also gonna check the 2 pinch bolts Mike mentioned.

 

[RempageR1]

Hi,

I`m sorry for the late reply. This is the bolt i`m talking about (and the one on the other side):

BOLT.JPG

I guess at full power all the oil moves to the back and with those bolts not tightened properly, the o-ring leaks...

Now the second part is perhaps a bit far-fetched but I have no better theory for it.... The rubber boot has a little hole in the bottom and with the U-Joint spinning fast, it might actually suck up some of that oil and leak it down the inside of the swingarm.....

 

[Redbone]

Sean or Damon can correct me if I am wrong but the back part of the transmission is somewhat separated from where the bulk of the oil is. There are passageways to get oil back there (and drain back channels) but the bulk of the oil remains in the front where needed.