replaced head gasket 2 months ago; now leaking

I replaced the head gasket on my 78 kz750 a few months ago. It has now started leaking again. I got the gasket in a gasket set. It seemed like it was two pieces of aluminum stamped together. I did not use any type of sealer. I'm going to redo the job but this time I want to get it right. Anyone got any suggestions?

Try to retorque the head bolts before you go and buy gaskets. Sometimes that will do the trick.

rctigers wrote:

I replaced the head gasket on my 78 kz750 a few months ago. It has now started leaking again. I got the gasket in a gasket set. It seemed like it was two pieces of aluminum stamped together. I did not use any type of sealer. I'm going to redo the job but this time I want to get it right. Anyone got any suggestions?

What kind of leak? If you mean it seeps oil along the front and sides of the gasket, that is (sadly) pretty typical for the 750 twins. You can minimize it by tightening the head bolts and the three small upward bolts, but I don't think it ever stops altogether. Mine has had a total of three different head gaskets in it's long life, and all (including the factory one) seeped oil a little. Look at pictures of 750 twins and you can usually see a dark line around the head/cylinder interface where the oil seeps and collects gunk over time.

Head gaskets generally do not use sealer, you just have to get the surfaces very clean and polished with scotchbrite pad. Make sure to replace the O rings on the oil passages going up to the head.

Make sure you use NEW O-Rings for the oil galley's. You can spray "Copper Coat" on the metal head gaskets. Also Lock-Tite 518 is a good sealer for many close tolerance flange surfaces, as long as its a real good fit.
Done right it won't leak.

Hey RC,

If you will put your location and bike model in your signature line we will be able to help you much more easily. AND perhaps if another KXRer lives near you hands on help may become possible.

My twin, and every other I've ever seen, also seeps as bountyhunter described. I prefer the carb cleaner spray option to the take the whole damn thing apart only to see it seep again option.

KZCSI

KZCSI wrote:

My twin, and every other I've ever seen, also seeps as bountyhunter described. I prefer the carb cleaner spray option to the take the whole damn thing apart only to see it seep again option.

KZCSI

I came up with a "fix" after the last rebuild: I use the heavy shop paper towels cut into pieces about 4" long and roll up VERY tightly into "gasket pieces" that I shove in between the fins at the front and push back until they are against the head gasket joint. You only need them at the front edge of the gasket. The oill seepage soaks into the paper towel then oxidizes away. It doesn't trail oil back along the head gasket which makes a mess and looks a lot better.

It's a mickey mouse fix, but it works. You only need a little strip of paper towel properly squeezed in with a popsicle stick.


For the record: I used the "copper spray" gasket sealer on the head gasket last time and it did not stop the seepage. I an not 100% convinced it seeps in the area between the head surface and the gasket, it may be working out between the gasket layers. Anyway, it still seeps. Tightening the small 10mm bolts slows it down, but be careful not to break them. They are small and the torque spec is about 100 INCH-POUNDS.