Any last advice before . . .

bigring

bigring

Active Member
Hey, thanks for reading.

I'm just about to put my '76 CB750 engine back together (after a much longer than I thought teardown and cleanup :o) with new gaskets, seals and hardware. Do you have any last bits of information for me? IE. "make sure to spray the head gasket with copper seal" or "don't spray the head gasket with copper seal", make sure to submerse the oil pump in oil and cycle out the air, etc.

I've got all my torque specs ready to go, parts diagrams, etc. and will be taking my time. Just looking for suggestions that some of the old timers or more experienced builders can offer. This is my first engine build.

Looking forward to the responses.

Cheers
 
For the head gasket, Honda came out with a bulletin to use a rubberized gasket cement for the two 6mm hole area on both ends of the block and head. Coat the mating surfaces to prevent a common oil leak in this place. Honda didn't use a sealer for the head gasket as it was designed to work without it. Using copper seal may not be enough for this location however. A factory new motor won't need sealer but a rebuild may need it after cleaning the surfaces.
There is an access plug to the main oil galley, 11 o'clock facing the point cover. Just above the point cover to the rear of the cylinder. Use a rubber tip on the oil can to seal, as you pre pump oil into all the engine lube ports. This is a good place to mount an oil pressure gauge for testing.
Above all, follow the instructions in the manual.
 

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Be very cautious with the cam sprocket bolts. Order brand-new OEM ones if possible because they're single-use parts (probably not made any more by honda though). If you reuse them, then don't over tighten. Use red loc-tite and torque to the lower end of the range listed in the FSM (remember, any lube on the bolts means that number needs to be somewhere in the middle of the range, not at the top).

The problem is that they can back-out if too loose, or shear if over-torqued. Both will be disastrous for the engine. Even if the sheared bolt is not shot hard enough to blow a hole in the head (it does happen), it's a one-in-a-million chance that a valve wouldn't bend. What happens is, the first bolt on the sprocket comes out, the sprocket moves out of time, the valves are now opening out of time, a piston slams into a valve bending it and also breaking the other cam sprocket bolt.

So that's something you want to take care of when putting the engine back together.

My expertise is in the smaller cc CB/CL engines, SOHC twins. But I imagine this is a common issue.
 
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