Oil Leak

So after 4 years or so from the last top end teardown, I have developed an oil leak. I had used a light film of grease on the bottom base gaseket, went try with the head gasket and copper spray sealent on the valve cover and oil pan. Looks like my leak is from the head gasket and not the base gasket. What do you think? I used foot powder to help track the leak down. Would checking the torque on the head worth bothering with? If I do have to replace it, I will make sure I use the copper gasket sealent this time.

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Hi Joe
Im sure it is the center o ring ( funny shaped cam chain cavity ring )
Maybe use a one piece gasket this time.
I would definitely re torque the head first and see what happens. Might just work or slow it down.
Over due upper end build ?? 1075 ? higher compression ? freshen up the head ?
Joe from Pitstop is close by if needed
Regards
Dave

Thanks Dave, I'll try the retorque first. But if I do go in, then I plan on a first over bore (pistions, rings and hones). Definetly change the valve seals and lap the valves while I'm in there. The last time I went in, I did so to replace the front cam chain guide. Got sick and tired of not being able to ride after being down for two months and just put everthing back together witout taking care of the needed work. At least this time I'll my other bike to ride while this one is down.

Have you been retorquing the head at regular intervals, such as when checking the valves? Reason for asking is that it's common for the gaskets to compress with time and when that happens the clamp load reduces. This is particularly common if using aftermarket gaskets. At any rate, it won't hurt to try torquing the head. Once they start leaking though they usually continue.

Did you retorque the head bolts after the first heat cycle after your last top end repair?

No haven't been priodically retorquing. Althouh I did retorque after the first heat cycle. I suppose I am hoping retorquing helps. I would like to defer this until Fall. Too much going on unfortunetly. Thanks for the tips guys. If I can't slow it down, I'm going to make time no matter what. Even though I have another bike, I can't stay without the KZ for very long.

Yep, its the center o-ring. Very common. I still use two-piece head gaskets with that o-ring. On my own motors, and the few motors I put together for friends, I have never had one leak!!! My trick is I use Three Bond TB1211 white sealant in that groove then I place the o-ring in the groove, then apply a thin coat of TB1211 to the top part of o-ring. Then put the head on. I never fire the motor up for at least 24 hours after I put the head on. I always follow the factory Kawasaki torque figures. First to 18lbs, then to 30lbs. And I follow their torque pattern to the letter. I ain't proud, I lay my shop manual right on top of the frame and make sure I follow it!!!

Now all that retorque stuff. When I do my first valve clearance check, I will set my torque wrench at 30lbs, and hit the nuts again. I would NEVER loosen the head nuts, and then retorque them.

Head and block decks must be flat or you're paddling upstream.

The 750 twins all leak oil at the front of the headgasket. You can see the slime trail as the oil blows backwards. On mine, I roll up a paper towel and wedge it in between the fins to keep it under control.

bountyhunter wrote: The 750 twins all leak oil at the front of the headgasket. You can see the slime trail as the oil blows backwards. On mine, I roll up a paper towel and wedge it in between the fins to keep it under control.

Head and block deck warpage .002" or less? These engines didn't leak new. My J engine didn't leak until 25 years of abuse. Flat decks, new OEM head gaskets, and they don't leak. Gasket glue on warped decks is a temporary fix.

And be careful who resurfaces your decks. Belt sanders, which I've discovered many builders use to resurface, do not make decks true-flat. Always confirm with a straight edge before assembly.

APE is the best out there for quality machining on a KZ.

I like watching this guy. As he says at time 1:12 "Some of you going to like it; some of you going to hate on this." Ed

my error Sorry!!!