Oil leak found...now what?

I finally found the leak from my KZ750H3 engine. Someone here was right and I was wrong. It is the tach cable input on the head!

The seal is an O ring and I put in a new one, but it still leaks. Any ideas what to try next? Thanks!

thats the drive for your tach does the tach work?Lots of old HORRO stories of cable drive tachs come to mind right now

Yea, it's the tach cable (I'm not awake today). Tach works fine. I took it apart and found an O ring under the screw-on end. It was shot so I found another (same size-but not a Kawa replacement)and reassembled it. Still leaks and makes a mess. Was wondering about using some hi-temp silicon on the ring?

I couldn't find the exact one, but this is what you need:

Tach Seal

If you call Z1, they will let you know if it will work, or get you the right one.

Just gasket maker or a new O-ring won't do it, trust me I tried forever.

Good luck.

There is a double seal in there one at the head and one at the cable from the sound of it you did the seal at the head.these cable drives are well known to leak Ive never tried to rebiuld a tach cable drive seal just always bought new ones but I would be interested in trying.PS it only has to hold about 2 to 3 psi so it shouldnt be that hard Im gonna go take one of my old ones apart for something to do Ill let everyone know what I find

There are 3 possibles for leaks there. There's the seal mentioned in the last post, plus the oring that seals the whole thing to the head. They are a complete pain in the azz because it's hot up there and rubber doesn't like hot, hardens and leaks. There's one more too, there's a paper gasket that seals the cable to the drive. First time the cable is removed the gasket is gone never to be seen again. You can make your own gasket out of a cracker box cardboard and sometimes that's all it takes to seal the leak.

Hummm...okay, except for the big O ring, I didn't see the others mentioned. Does anyone have an exploded view of this connection? Thanks!

where the tach cable goes in to the internal fitting there is a small seal that drys out over time and shrinks. replace properly and your problems will magically disappear

That's why I was asking if anyone had a diagram. Other then the big O ring, this has no other gaskets/rings of any kind. I need to see where they fit in.

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The rubber shaft seal includes a tiny fine spring to help grip the shaft spinning around inside the seal.

An old hardened seal may look and feel like a piece of carbon and require being picked out in small chunks (using something like a dental tool).

The seal prevents oil from escaping along the shaft.

The 0-ring prevents oil from escaping around the case.

Even with the tach cable removed entirely, there should be no oil leakage whatever at any rpm. Just observe the end of the shaft as it spins.

Tightly sealing the knurled fitting where the cable attaches to the case to avoid leakage from this area is a band-aid remedy :X that simply allows the escaping oil to be contained within the cable sheath. :pinch:

Good Luck!

Patton, thanks! Just what I needed!

Hi, I've got the same problem with a drippy tach cable. Were you able to fix the problem? I think I'm going to try putting a new seal and O-rings in if I can, anyone know what size O-rings those are? Also, is this a pretty simple thing to do?

Thanks