lm, do you know how tall it's supposed to be?
I just picked up two NOS ones from a Honda dealership in town. I just push them down in there until they seat, I think they're like 9mm out of the barrel block?
Head Gasket Leak CA72.
Just wanted to put an update out there, I bought new knock pins and installed them. Put the breather plate on, new crush washers, o-rings, etc, etc.
It still leaks from the same spots. I've been trying to sell the bike but people are turned off by the leak and I don't blame them. Not sure what else to do with the guy now. If I take it to a professional I presume to pay more than I bought the bike for and I don't love her quite that much.
Hey G-Man,
I know I posted a giant dump of pictures awhile ago, that's when you guys discovered I was missing my metal breather plate. I do appreciate that help. Ironically, when I first got the engine it did NOT leak and it was missing that breather plate; weird right? I'm not sure what information I should repeat to update everybody. I don't have a current picture of the engine, but I'll attach where the leak is, it's definitely coming from the head gasket and not the camshaft cover. I can shine a flashlight on the head gasket as it's running and I can see very small bubbles forming. It doesn't leak profusely, just a steady drip once the engine is turned off. Right now I've got the new base gasket below the pistons, I've cleaned the surfaces between it and the head, have one head gasket (not two anymore like I accidentally did the first time), with no gasket sealer, I have two NOS knock pins with new green o-rings on them at the exhaust side two posts where they slip down into the engine barrel a few millimeters, they're both sticking up equally. Then I put the head on, then one rubber gasket, then the breather plate, then the other rubber gasket then the head plate lid. On the head plate lid I put four new steel crush washers in the middle four posts and four new copper crush washers on the outside four posts. The studs are not stretched and the acorn nuts are not bottoming out. I put the two bolts on next to the spark plugs then I start torquing down the head bolts. The head bolts are currently torqued to 21 pounds per square inch. They're damn tight, it takes considerable effort to tighten them more and I don't want to break my cylinder studs. I do not torque down the bolts next to the spark plugs, I just tighten them to "really tight, but not damaging tight". After I ran the engine for awhile and it was still leaking, I pulled the engine again and torqued the head nuts to 24 pounds per square inch (even though they hadn't budged, they were still at 21ish). That's where I'm currently at. Maybe the oil is the wrong viscosity and is too thin, or maybe that's the reason the engine didn't leak before I pulled it apart is that the oil was too thick and mucky to make it out of some leak spots? I don't know. I hope any of this novel helps. Ed sent me a PM and I'm going to discuss this with him soon, he'll probably have some pointers.
Just a thought
Are you sure it is not the side cover on the head that covers the cam? Mine leaked from there. I cant recall if the rocker pivots weren't completely home or there was damage to the mating surface but it was weeping down the front of the motor. I ended up cleaning thoroughly and using a silicon sealant as well as the gasket and it fixed the issue. I agree. The leak is above the head gasket and unlikely to be from there. Either the cam cover or the dreaded separation of the combustion chamber "skull" from the head casting.
If the former, should be an easy fix. G
Last edited by G-Man on Sun Jan 25, 2015 12:57 pm, edited 1 time in total.
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160 '66 Matchless 350 '67 CL77 '67 S90 '77 CB400F
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