So, I replaced the head on my 93 CBR600F2. New head gasket, torqued to factory specs, motor back in frame and filled it with water. leaking right below the #2 exhaust port between the head and the block. The head and block were prepped (so I thought!) so this is baffling to me. It's just a slow drip on an unpressurized system (I haven't started the bike). Any suggestions before I drop the motor and pull the head again?

TIA...

 

Did you check the head and block surfaces with a straight edge to see if they were straight and flat?

 

^ Yep, the head gasket didn't seal for some reason. Regardless of the reason, the head will have to come off and the gasket replaced. While it's apart, double check the block deck and the head mating surface for irregularities and/or cracks.

 

I realize that this is probably resolved by now, but, if not, I have a question: Torquing to spec is very important, for sure, but did you ALSO make sure that you torqued the bolts in the correct sequence, and torqued them up in graduated steps... in sequence?
Let us know if you got it licked already.

 

^^ there's a sequence to torque these bolts down? I just gradually went outside then diagonal through keeping the bolts at the same level. However I'm not leaking coolant from the bike it's just disapeering

 

Yep, there sure is. I'm not sure of the specific order on these engines, but it usually starts on the center most bolt (s) of the head and radiates outward. Some engine builders will even torque to 50% on the first pass, then another pass at 75%, and finish up with the final pass at the full torque specification. This is to ensure an even crush of the head gasket.

 

I torqued to spec and to sequence when I re-assembled. It stopped leaking and there is water in the radiator still, so I'm planning on starting it and seeing what happens. Pretty sure I'm gonna have to pull the head off again. I was installing the exhaust and pulled a stud. More delays...

 

Pull the head for an exhaust stud? You should be able to heli coil it without taking off the head.