Cylinder Gouged

[P.Martinez]

Just completed disassembly of the engine in my '67 CL77. One of the problems discovered is a gouge in the upper cylinder wall that measures approx. .25" wide x .38" long x .010" deep and is wedge-shaped, that is it starts out narrow at the bottom and gets progressively wider at the top. It looks almost as if the spark plug electrode broke off and got wedged between the piston & cyl. According to the previous owner the bike did not noticeably burn oil in this cyl., and seemed to run fine when he put it away about 20 years ago! This mishap happened before he owned it, as someone (orig. owner), did put a new piston in the problem cylinder and put it back together. My decision to make is to go trough the expense of re-boring both cylinders and assemble with new oversize pistons & rings, or just put everything back together as is as I don't. plan on doing any extensive riding with the bike when done. So, question is, can someone on the forum give me a ballpark idea of the cost to have a shop do this type of work? Thanks.
Phil M.

[Hahnda]

Cylinder boring in my are runs about $50 per cylinder.

You will then have the cost of pistons and rings. Minimum $200 on those.

It just snowballs from there. You will need gaskets and might as well do seals. You might find a notched chain tensioner etc.

[P.Martinez]

Thanks for the info. Kevin. Will probably go ahead with the rebore, new pistons, etc. Already had to replace the cam tensioner roller as it was pretty chewed up.
Phil M.

[linmictil2]

I have had 3 done so far. Around Lansing Mich area I pay $ 89 per cylinder to bore. I would suggest having the machinist tell you how much you need taken off then find the piston and rings at any place on the web . When you get them take the parts back to the machinist and let him do his thing
If you have gone to the trouble of tearing it down you might as well make right. .. Just my thoughts
Regards Mike

[P.Martinez]

Thanks Mike. Talked to the local Honda dealer yesterday for an estimate on boring the cylinders. The use a machine shop in Watkins Glen that charges between $65 - $75 per cylinder fitted to pistons that I supply, which appears to be a fair price, so will be going this route. Thanks for the reply.
Phil M.

[48lesco]

Hi - Couple of questions. What does the rest of the cylinder look like, and does the top ring even touch the gouge? How many miles on the bike? If it's still close to spec, I would be inclined to just hone it and put it back together with new rings. You'll have to go to at least the second oversize (.5mm) to take out a .010" deep gouge. I'd be inclined to spend the money elsewhere.
-48

[P.Martinez]

The broken sparkplug electrode (if that was indeed what it was), somehow got past the top ring and got trapped between comp. rings #1 & #2. So yes, the gouge is past the top ring. There are scrape marks along the length of the cylinder, but not as deep. I would estimate at about .003". Also, whoever made the repair used a piston that does not match the original. One piston is marked "CB77" and the replaced piston is marked "C77". The "C77" piston weighs 10 grams less than the other, probably not a good thing!
Phil M.