1982 CBX On the road again project

[bobcat]

You won't be able to get the ring gap correct until you get the piston to cyl. clearance
correct (within factory spec.) See Mike Nixon's articles about cyls/cyl. boring/honing ;
themotorcycleproject.com.

Looks like it's either bore the cyls/new pistons and rings or find another unbored cyl. block
and use your pistons and rings. My choice would be a fresh bore/new oversize pistons.
Each cyl. should be bored to the piston that goes in that hole since pistons vary slightly
in size.

[daves79x]

That is too wide for the ring gap, but more importantly, your cylinder/piston clearance is over .004 inch. Standard from Honda is .001. That is WAY to much clearance. Your engine will be very noisy. You can buy first-over Honda rings and file them to the correct ring gap, but the noisy engine will still be the result. I suspect your cylinders were still well within spec before the machine shop got hold of it. All you do for a re-ring is lightly hone the cylinders to break the glaze with a non-aggressive hone. You can't take out any material. Your guys obviously did. They should have known this. You are stuck with doing an over-bore and new pistons. No shame in that with 50K miles on the engine. Just more $$$. You can buy first over aftermarket sets, or go 100cc over with a big-bore. Cost of the boring is the difference. I'd just go first-over.

Now to your head - I assume the shop reconditioned the head? If they were not very careful with reconditioning the seats (ie, they didn't just aggressively cut new seats with a seat cutter), you will have a surprise when you go to re-shim the valve clearance. You will find, if that's what they did, that you will need very thin shims to set the clearances. They also should have replaced at least all the exhaust valves, likely the intakes as well with 50K miles. If they just ground the valves, that's bad news too. They should have also installed verified Viton valve stem seals.

Perhaps I'm being overly pessimistic, and your shop does a lot of DOHC Honda heads. But you need to know exactly what they did.

Dave

[Larry Zimmer]

Bob, your statement about boring to a piston is so very spot-on. And, when the shop returns your block and pistons, be certain they give it to you with the respective pistons related to their bores. Size does matter!

[Maddex]

Yes, cylinders was in the spec before honing, but guy from machine shop convinced me that hand drill honing want give me the best results (he said that the cylinders are not perfectly straight), and he will do that for me with proper machine.
What pistons sets you can recommend?

[daves79x]

The cylinders are never perfectly straight if they have any miles. The purpose of honing for re-ringing is not to try to make them straighter, just to break the glaze and give the new rings some bite to seat. But that’s gone now.

Cruzinimage makes generally decent piston sets for reasonable money. If you go Wiseco or J&E, you’re looking at $1200 for pistons and rings.

Dave