Oil leaks
gasketI bought the gasket kit from Tim at classic and it's working fine. 18 ft-lbs but will take another look in the spring after its been run for a couple hundred miles
67' CB77
66’ CB77 65’ bomber 68’ hellcat
Generally I'd never use sealant on gaskets, as you said, that's what the gasket is for. I do sometimes use a smear of grease on some of the larger gaskets to help them stay in position while assembling. I can't imagine the brief run would have hardened the head gasket but is it worth taking the risk with all the work involved. Ask yourself, what's your hourly rate at work, would a new head gasket cost more than you could earn in the couple of hours it will take you to replace it?
With the copper gasket are you still using the O-rings on the corner studs? Are the acorn nuts possibly bottoming out on the end of the studs? The copper head gasket will need to be annealed to use over again. A thin even coat of aluminum paint, sprayed on both sides of the gasket, and allowed to dry will help it to seal.
'65 YG1
'65 CB160 '66 CL160 '66 CL77 '78 XS650 '79 GL1000 '69 T100R '68 TR6 '69 T120 '72 750 Commando my company car is a Kenworth
Geoff - take the point about time and effort involved though my hourly rate is pretty low now as just retired a couple of weeks ago! (and need to get new gasket from US).
Mike - I am still using O-rings with the copper gasket, though leak is base gasket. Need to check for bottoming out. of acorn nuts. Greg
Increasing the torque made little difference so I have stripped the engine down again.
I was wrong, it is a 9 hole gasket, there is a brass tube where the 9th hole is. I checked and the acorns are not bottoming out. Looking at everything I am struggling to see what the problem is but as soon as the torque was taken off the studs, oil seeps out from the base gasket and this is where the main problem is. With having the larger bore the amount of base gasket is reduced to accommodate the larger sleeves but there is no sign of damage or any obvious problems that would cause leakage. Greg Greg
Can you send a picture of the top crankcase and the barrel around the 9th hole. The brass tube sounds a bit suspect. G
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160 '66 Matchless 350 '67 CL77 '67 S90 '77 CB400F
Hi there, sounds like you are getting near to solving the problem, however, I'd be cautious of increasing the recommended torque on the nuts/bolts. Apart from the obvious risk of pulling a stud out of the casing all bolts have a degree of stretch, this stretch helps keep things tight and if exceeded the bolt goes beyond its elastic limit and is very near its yeald point.
Just for info, A lot of car engines have what they call stretch bolts on the head, some are single use and some manufacturers will give a measurement of bolt length so after each use it can be measured. The ones I disliked were the ones tightened to a specific torque, then you turn them another 90 degrees then you go round in sequence and turn then another 90 degrees. Always seemed like they were being over tightened but they never actually were a problem. Good luck with sorting the leak.
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