Oil Leak From Head Gasket. 1982 KZ550LTD

Hi, in the last couple of weeks, I have noticed a growing oil leak that seems to be coming out between the head and block. Leak seems to be worse on the left side. Tried re-torquing the head bolts, but they are tight as heck. Checked the tach drive area and it is pretty dry. The entire front of the motor is covered as well. I suppose the leak could be in the front and being blown around to the sides so it appears to be coming out from the head gasket? Kind of grasping at straws right now. Any ideas?

I have seen people using synthetic oil or synthetic blend and oil starts weeping through the gaskets. Have you recently changed to a synthetic oil?

If it's leaking, it's not a gasket. It's bad rubber orings. They use an oval shape oring on each end of the cylinder between the cylinder and head that harden eventually and leak. Of course you have to change the head gasket along with the orings to repair unless you feel lucky reusing the gasket.

If not already done, would assure:

(1) No loose exhaust clamp (loose or stripped, stripped stud, cracked clamp, etc.);

(2) No leaking exhaust gasket.

The goo oozing through a leaking exhaust port may easily be mis-diagnosed as oil leakage from some other source.


If an oil cooler is fitted, would also check integrity of hoses and clamps where attached to the finned cooler.


Good Luck!

Yes to possible o-rings leaking, and if you have oil at the front, could be heaqd gasket seeping as well. Degrtease the area, and see if the base gasket is leaking. I've replaced the headgasket, without bothering the base gasket when my side o-rings were leaking. There are 3 nuts holding the cylinder on to the case. Find out what's leaking and where.

+1 on the synthetic oil issue.

Hi guys, thanks for the replys.

1 - Unknown header and pipe from P.O., pod air filters. Carbs are "vintage takeoffs" that have never been touched. Still have the litle plugs in the adjusting screw holes. Feels like it is running a little lean in the mid to upper rpm range. About 4.5k on this setup, unknown for sure, but guessing about 38k total miles.

2 - Checked the vent tube during lunch break and it is unobstructed. Really thought this would be the problem as the oil gusher came on pretty sudden.

3 - Used a can of the Gunk gell spray and a few bux at the hottest car wash in town this evening after work. Engine is now completly clean and dry. Added an ounce of dye and rode around for 5 or 6 miles, then hit it with the UV light. Hmmm..Engine is still clean and dry. Only found a VERY small seep at one of the #1 exhaust pipe studs, (just the stud, not the pipe inlet), and a little bigger seep that seems to be coming out of the #2 exhaust pipe inlet. All the stud nuts are still tight.

4 - When I ran the valves this spring, I remember the compression being O.K. I can't remember the exact number, but I remember looking it up in the FSM and deciding it was alright.

5 - Running O'Reilly house brand 10-40 oil. Have changed the oil about 12 times in 4500 miles trying to get the dirt out of the motor. When I got it, it had been running for an unknown amount of time without the boots between the airbox and carbs.

I'm gonna try and run it 20 miles or so tomorrow afternoon after I get done with some work around the house and see if a bigger leak presents itself. What I have seen so far doesn't look like what was dripping on the concrete and covering the entire engine every night after work.

In the meantime, any ideas what is causing the seepage at the exhaust ports? Rings or valve guides?

Sorry for the book length post. Just trying to cover all points.

Thanks for the help guys.

maagman wrote:

... VERY small seep at one of the #1 exhaust pipe studs, (just the stud, not the pipe inlet), and a little bigger seep that seems to be coming out of the #2 exhaust pipe inlet. All the stud nuts are still tight... In the meantime, any ideas what is causing the seepage at the exhaust ports? Rings or valve guides?....

In the meantime, any ideas what is causing the seepage at the exhaust ports?

Exhaust Gasket from Z1E

Tight stud nuts aren't necessarliy the answer, because the clamps may bottom and leave the old crush gasket still leaking.

Rings or valve guides? -- don't think so. Because any oil from the combustion chamber (or oil getting past valve guides or valve seals) should be blowing out the end of the exhaust system, and not escaping through the head exhaust port.

On some KZ engines, it's reported that when re-threading or chasing (cleaning) threads inside head where exhaust studs are fitted, a possibility exists whereby the tap may protrude on through into an oil channel lying closly behind the stud hole. In that event, oil may escape around the stud threads to the outside. Could be addressed by stud removal, thorough cleaning, and re-assembly with Permatex high temp thread sealant applied to the threaded area. Am betting against this being the problem in the case at hand.

Good Luck!

Well I found my oil leak, all 5 of the bolts that go up into the head from the cylinder, (3 in the front and 2 in the back), around the cam chain were gone. Cant imagine how I lost all 5 of them at once, but I got 5 bolts and installed them, recleaned the motor, changed the oil with some fresh dye, and 2 trips to work and back and my motor is dry as a bone.

Thanks for the help everybody.