Leaking head and base gaskets...can they be re-torqued?

[GMX]

CL450 K4 sat for many years ignored and unloved.
I rebuilt the carbs, adjusted the cam chain and valves and set the points and timing. Coils and condensor checked out aok.
She starts right up and runs strong, but after about 20 miles, it looks like oil is seeping at the head gasket and cylinder base.
I think this motor may have been rebuilt at some point as the mounting bolts were all facing the wrong way from the parts diagrams indicating it had been removed from the frame.
But who knows anything for certain on a 50+ year old bike?
I really don't want to rebuild the motor on this bike but would like to know from the more experienced guys here if the head bolts could be loosened and retorqued
to help slow or stop the oil leaks.
If so, what would be the correct step by step method?

 

[MrPepper]

Id say worth a try!
I loosen the headsteady prior to retorque but don't know if that makes a difference

 

[ancientdad]

I'm sure it could work in some situations and obviously it's worth a try, but all the times I've done it haven't stopped any top end leaks ever, and really didn't change any of them either. There's also the possibility that a cam chain left too loose for a long time has carved a thin spot in the cam chain tunnel somewhere that is now leaking from a pinhole in it somewhere.

 

[GMX]

Well, darn. OK
I may still give it a try.
The FSM Section 3.2 Cylinder Head Reassembly says the nuts should be loosened in reverse of the tightening sequence.
Torque is 21.7 ft-pounds as in the sequential diagram.
Should the crankshaft/valves be in any particular position when slightly loosening and then retorquing the head bolts?

 

[ancientdad]

Well, darn. OK
I may still give it a try.
The FSM Section 3.2 Cylinder Head Reassembly says the nuts should be loosened in reverse of the tightening sequence.
Torque is 21.7 ft-pounds as in the sequential diagram.
Should the crankshaft/valves be in any particular position when slightly loosening and then retorquing the head bolts?

Not that I'm aware of, no.

 

[stl360+450]

The topic of retorquing a head has been and remains a little mysterious to me.

• Sometimes it is mentioned that the head should be checked/retorqued after a freshly built motor is put through a full heat cycle or some small number of miles. I have checked the head when the nuts are exposed (CB350/CB450), but generally not when they are covered (CB360/CB750). Not sure what other people do, nor what is recommended.
• I tried retorquing the head on my recent CB350 build to cure a leak. It didn't work because it wasn't a head leak! I rebuilt the top end twice before realizing that, so three sets of gaskets when I only needed one. I went beyond the torque listed in the FSM and I recall other members mentioning that they do that as a matter of course on their rebuilds. So, maybe you could consider increasing the torque slightly rather than retorquing the head.
• The head gasket should only be used once because of the crush rings around the cylinders, so the nuts must be loosened and tightened individually. Otherwise there is a big risk that things will move and whatever seal was achieved could be compromised. If one accepts this idea, then it is natural to ask whether the torque sequence makes any difference for this operation. I'm not sure it does, but I think I would use the tightening sequence rather than the reverse sequence, especially if the torque is being increased.

We all know the correct way to address a bonafide head leak, but I will agree that there is little to lose by trying something like this as long as one does not go overboard with the torque wrench.

 

[GMX]

The topic of retorquing a head has been and remains a little mysterious to me.

• Sometimes it is mentioned that the head should be checked/retorqued after a freshly built motor is put through a full heat cycle or some small number of miles. I have checked the head when the nuts are exposed (CB350/CB450), but generally not when they are covered (CB360/CB750). Not sure what other people do, nor what is recommended.
• I tried retorquing the head on my recent CB350 build to cure a leak. It didn't work because it wasn't a head leak! I rebuilt the top end twice before realizing that, so three sets of gaskets when I only needed one. I went beyond the torque listed in the FSM and I recall other members mentioning that they do that as a matter of course on their rebuilds. So, maybe you could consider increasing the torque slightly rather than retorquing the head.
• The head gasket should only be used once because of the crush rings around the cylinders, so the nuts must be loosened and tightened individually. Otherwise there is a big risk that things will move and whatever seal was achieved could be compromised. If one accepts this idea, then it is natural to ask whether the torque sequence makes any difference for this operation. I'm not sure it does, but I think I would use the tightening sequence rather than the reverse sequence, especially if the torque is being increased.

We all know the correct way to address a bonafide head leak, but I will agree that there is little to lose by trying something like this as long as one does not go overboard with the torque wrench.

Hmmm,
Your post does make sense to me, especially about the head gasket only being used one time, so not to loosen all the nuts at once.
I have not tried anything yet, but will try checking the torque (21.7 ft-lb) as per the FSM sequence one nut at a time and see if there is any movement. If not, I will go back and increase the torque slightly on each nut, again, one at a time in sequence and see if that makes any difference.
For that procedure should I loosen a nut first and then increase torque, or just see if I can increase torque without first loosening a nut one at a time?
Just not sure how much over I should attempt..any ideas on that?

PS if your leak was not a head leak, what was the problem with your CB350? Just trying to accumulate knowledge from those with more experience here... thanks.