Need to brain storm some ideas to stop my oil leak issue

Shermanator86

Shermanator86

Big guy on a little bike
307722_662206536281_65000676_33372917_359978919_n.jpg


Ok so trying to get the bike back on the road for this season and this is my hold up, replaced this seal and rode on it for about two months before it started leaking again. Its the push rod for the clutch, checked the size of the rod and it is in spec so thats not the issue. Don't want to spend another $40 on another 30 year old seal just to have it do the same thing as this one. So I need a new plan, My best idea so far is to find another seal with a little tighter ID and close to the same OD and glue it to the old one then use some RTV sealant around the outside. Problem I have with it is finding a seal with a 7mm id (I think I'll double check that measurement when it get home) and it just seems like a rigged up thing which is fine if its the only way but not my first choice.
I just want to get this thing to stop leaking before I put the rest of the time and money into it I was planning on the spring so any advice or ideas would be greatly appreciated.


* Bike is a '78 kz400b if that helps
 
The question is which side is it leaking, the shaft side or the case side.


If it's the case side, you can drain the oil, remove the seal, clean the case very well, and reassemble with RTV to ensure that the seal to case is tight.


If it's the shaft side, you need to replace it.


FYI, a lot of these oil seals are standard items and can be had from hydraulic supply and other industrial supply.
They are listed by dimension, O.D. X I.D. X Depth.


You may well be able to find a nice new seal that hasn't been sitting in a baggie for 20+years that way.

Another (less likely) possibility is that the clutch pushrod is spinning with the clutch. (the seal will wear much more quickly if so)
There should be a ball bearing trapped between the clutch and the pushrod to isolate the rotation. If it is no longer there or has become welded to one side or the other, then the shaft may be spinning.

Best of luck!


It can be a real challenge to get these old bikes completely leak free...
 
Bozz said:
The question is which side is it leaking, the shaft side or the case side.


If it's the case side, you can drain the oil, remove the seal, clean the case very well, and reassemble with RTV to ensure that the seal to case is tight.


If it's the shaft side, you need to replace it.


FYI, a lot of these oil seals are standard items and can be had from hydraulic supply and other industrial supply.
They are listed by dimension, O.D. X I.D. X Depth.


You may well be able to find a nice new seal that hasn't been sitting in a baggie for 20+years that way.

Another (less likely) possibility is that the clutch pushrod is spinning with the clutch. (the seal will wear much more quickly if so)
There should be a ball bearing trapped between the clutch and the pushrod to isolate the rotation. If it is no longer there or has become welded to one side or the other, then the shaft may be spinning.

Best of luck!


It can be a real challenge to get these old bikes completely leak free...
Click to expand...

Its leaking around the shaft, the ball bearing it still in place and moves freely. I'll have to look into finding a new seal for it, bitch of it is you have to split the case to get to it (later model 440s just use a c clip). Wouldn't mind if it leak just a little but this thing has just a constant stream leaking out because the its and oil passage right behind it. Thanks for the advice though I'll have to find the complete dimensions of the seal and do some searching.
 
Bozz said:
FYI, a lot of these oil seals are standard items and can be had from hydraulic supply and other industrial supply.
They are listed by dimension, O.D. X I.D. X Depth.
Click to expand...

As far as I've been able to find, this is one of the few that aren't available from industrial suppliers. I ended up buying a complete sets when I rebuilt my CL350 and CB400f. They weren't in Honda packaging, but they're all made by one of the big seal manufacturers, so they should be the same quality.
 
My kz has the same issue. Mine started leaking after i put the cases back together after rod bearings. F@&$. I bought a new seal. Not sure if its NOS or not. Someone on the kaw twins forum said he cleaned his really well and super glued a new seal to the outside of the old seal. He said it works. I was going to try it before i decided that im just gonna tear it down after bike week. Drives me crazy. Ive never had such an oil leaking bike. I love it but come on....
 
It might be the angle of the pic, but the seal looks cocked to me. Is it pushed in further at the bottom than it is at the top? That would cause the ID to be egg shapped and not seal quite right.
Can you get a deep well socket that just matches the OD and gently drive it in straight?
 
Like adc said pry it out or use a screw, chamfer the edges of the case very carefully with a razor blade so you don't nick the new seal, clean and remove any burrs on the clutch pushrod. Put it back together with a thin film of rtv on the case side of the seal. Similiar set up as the xs 650. There are a bunch of walk throughs on the yamaha forums...
 
Hoosier Daddy said:
It might be the angle of the pic, but the seal looks cocked to me. Is it pushed in further at the bottom than it is at the top? That would cause the ID to be egg shapped and not seal quite right.
Can you get a deep well socket that just matches the OD and gently drive it in straight?
Click to expand...

Just the angle of the pic, the seal sits in a good 1/8 inch grove in the case so not really any way for it to get out of shape
 
Tim said:
The rod could also be worn.
Click to expand...

did a quick check, seems to be a uniformed dia trough the whole area that come in contact with the seal. But I'm going to pull another rod out of my roommates bike and check it.
 
AlphaDogChoppers said:
Seriously? You can't just twist a lag screw into it and pull it out?
Click to expand...

could pull it that way, but no way to replace it with out the case split. the case has a good sized grove the seal sits in so the seal is quite a bit larger than the hole you can see in the pic
 
reelinfeele said:
My kz has the same issue. Mine started leaking after i put the cases back together after rod bearings. F@&$. I bought a new seal. Not sure if its NOS or not. Someone on the kaw twins forum said he cleaned his really well and super glued a new seal to the outside of the old seal. He said it works. I was going to try it before i decided that im just gonna tear it down after bike week. Drives me crazy. Ive never had such an oil leaking bike. I love it but come on....
Click to expand...

I'm on the twin owners forum to, do you got a link to that thread? I'm damn near ready to just get a 440 case just for the revised seal lol
 
Here are some pics of when I replaced the seal last summer, you can see the grove the seal sits in, in front of the sprocket
IMG_20110824_180119.jpg

IMG_20110824_180113.jpg
 
Swivel said:
I think its case splitting time again,sorry.I hope you clean the case mating surfaces cleaner than grannies best dish plates before putting them back together.I doubt a seal sitting in a wharehouse would go hard or shrink.You need to use thin coats of Yamabond grey around the seals and on both the mating surfaces.I've worked on harder to split bottom end cases than those,they look easy to me.Use correct rubber grease on the pushrod in that seal when you put it in so it does'nt score or tear the seal when it spins.Look at the pushrod with a magnifing glass and if its got scratches on it get a new one.
Click to expand...

yea the case is easy to split just takes time, and it doesn't leak at all anywhere but the push rod. I'll have to see if I can even find another seal as the last one took some time to even find, they only made that seal for 2 years before they revised it to be replaceable with just a c clip.
 
Swivel said:
Don't feel too bad about it only leaking from one place,get a rat Norton Commando that leaks from about ten places to get a real perspective on oil leaks. ;D
Click to expand...

haha i know i know i shouldn't bitch about one measly oil leak, my buddy has the older model kz400 that leaks from everywhere lol
 
Here is an idea to try.
Take a piece of 3/16" or 1/4" ID rubber tubing, whatever fits snugly over the clutch rod. Use fuel injection gas line. (more reinforcement.) Cut a piece that fits snugly between the seal and the clutch actuator. Clean the seal pristine clean with spray carb cleaner. Put some silicone sealer on the face of the seal, and slide the tubing onto the clutch rod and bed the end of it in the silicone. This might stop the leak or at least slow it down enough to make it tolerable.
 
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