Oil leak

[shaggy]

Have just rebuilt my engine and have an oil leak at the front between cylinder and cylinder head only in the one place, think it may be a problem with the funny shaped o ring that goes at the top of the cam chain tunnel anyone else had this problem in the past. Just see a drip forming in the second photo.
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[BAFF1960]

Hi.
Yep, looks like a leak from the cam chain tunnel O ring. Was it a pattern one? Noticed that pattern ones don't sit perfectly in the groove compared to originals when rebuilding my motor. It been recommended to apply some silicone gasket around the tunnel aperture when assembling to aid sealing although its not stated in the service manual. I've not had an issue with leaks when using genuine ( very expensive ) Kawasaki parts for head assy. Another alternative is to use a Cometic performance one piece gasket.

[zed9]

Might just need torquing down after being run for a while. Try torquing them all in correct order couple of times.
Not sure if you can add couple more lbs of torqure if that dont work though others on here am sure can advise on that.

[Gray17]

Think youve been unlucky, i just fully rebuilt my own Z900 A4 motor used Arena gasket set, which is a pattern part set, def no leaks from mine. That said i did use a sealer on all the casing gaskets, but not on head or barrells. As advised you could try re torqueing the head down again, be careful adding a few more pounds though, the threads are 40 years old as probably are the bolts you dont want to shear them.
If its only minor you could see if it cures itself after a few run ups to temperature? If its pouring out, you may have to re strip down and replace gaskets and o rings again.
Annoying im sure!
Whilst i dont have oil leaks, i do have a slight fuel leak from L/H carb overflow, so think the float is either sticking or not set correctly, also awaiting arrival of voltage reg as its charging at nearly 16v.
So mines not all plain sailing either.
Think the general consensus is you always need to fettle a classic bike, its part of the pleasure of ownership!

[BAFF1960]

Just another thing to watch for when running after assembly. I had what looked like a leak from the back of the head at the tunnel O ring when first using after the rebuild. It turned out to be a leak from a not tight enough cam cover allowing oil to dibble down. Was a bit too cautious with the bolt torquing. Easier to see the cause on a black engine. Its always worth rechecking any joint sealing torques after a few heat cycles.