Oil Leak KZ900

I've been putting some miles on a KZ900 I just completed restoring and noticed it has a small oil leak in the head that appears to be coming from the head gasket.  This is curious because I can't imagine where oil could be coming from that would seep out of the headgasket.  I can see that the gasket was changed by the PO and it looks like he put some kind of sealant on the mating surfaces, probably because he was too cheap to buy a new head gasket.  I'll attach a picture.  If anyone has any ideas, I'd love to hear them.

 

Very common oil leak area 
The cylinder studs  on the outside edge of the motor serve as oil galleries to get oil to the  head / cams
 

Thanks for the reply.  Is there anything I can try before pulling the head off?

wrote:

Thanks for the reply.  Is there anything I can try before pulling the head

retorque the head

Tightened the 4 outside nuts to 40 ft lbs, didn't want to push it any farther. That seemed to help but not stop it.  They were pretty loose, like less than 30 probably. I wonder if these bolts could take 50 lbs? (Yes, I'm cringing also)  I think I remember an old mechanic telling me something about injecting sealant into the gasket at the point of the leak with a hypodemic needle chefs use to baste the inner meat on a roast or a turkey. 

wrote:

Tightened the 4 outside nuts to 40 ft lbs, didn't want to push it any farther. That seemed to help but not stop it.  They were pretty loose, like less than 30 probably. I wonder if these bolts could take 50 lbs? (Yes, I'm cringing also)  I think I remember an old mechanic telling me something about injecting sealant into the gasket at the point of the leak with a hypodemic needle chefs use to baste the inner meat on a roast or a turkey. 

The head should be torqued uniformly.  Not extra tight in any particular location otherwise it may warp.

Once a leak starts it's rare to fix it through torquing.

After a rebuild it's important to retorque a few times until you are confident the torque is not falling off any more.  If using aftermarket gaskets the torque fall off can be dramatic as the gaskets compress.  That's why it's always best to use OEM gaskets.

If you have stock studs 40 is too much.
Steve

When you replace the gasket (and you will), after the first start up, get it up to temp (ride it). Shut it off and let it get cold (over night). Re-torque the head then restart and get it up to temp again (ride it). Let it get cold (over night) and re-torque. Two times might do it. I did it 3 times on my KZ and was very close on the third. It’s a PITA but worth it in the end. YMMV, good luck.

If you dont have a factory service manual , you need to get one and follow  the  instructions  .
99 percent sure to fix leak  you will need to pull the head and maybe the cylinder block too if you disturb the cylinder base gasket.
You are scaring me  with only torqueing  the outer stud nuts and  not doing all of them in the proper sequence and to the proper amount . 
 Take a breath of air and regroup and ask for  more help here.
Best gaskets are OEM stock and Cometic. Stay away from other brands
Dave

Thanks for the input everyone.  I backed the 4 outside bolts off a bit and then torqued to the recommended 30 lbs.  If I have time tomorrow I plan to remove the valve cover and check the torque on the inside bolts.  I've heard Permatex Ultra Black can stop minor head gasket oil leaks by cleaning the area thoroughly and applying a couple layers of the stuff over the leaking area. I understand it probably won't be a permanent fix but for the cost of a tube of Ultra Black I figured it couldn't hurt and it's great stuff to have on hand in the garage anyway.  Got it up on the center stand curing.  I'll take it for a test ride tomorrow.  Expecting the Ultra Black to not work, iIs it possible to remove the head off a KZ900 without pulling the motor out? 

The  head and or the cylinder block can be pulled while in the bike. 
Manual ???????  Its all in there. 
These motors are very straight forward and easy to work on  , but must be done properly

I have the factory manual.