Help with some CB77 engine specs

[heyyou]

Hello All,

In the process of a tear down for restoration, I performed a leak down test on my ‘64 CB77 and concluded it was time to find the source of the leakage occurring into the crankcase on one of the cylinders. Looking around for my shop manual for my Superhawk, I vaguely remember the manual being lent to a co-worker from a company I worked for years ago. Any way, I’m going to check with the guys at the next VJMC meeting if they have a shop manual, in the mean time, I’d like a little help with a few specs while I get my hands on a manual. This will tell me what parts I will need to find. Please help with the following specs:

1. Piston skirt to cylinder tolerance?
2. Ring end gap tolerance/range?
3. Allowable cylinder taper?

The other question I have is:
Years ago I would press out the out the sleeves of my Hondas, and replace the sleeves when I wanted to convert a bored out high performance engine back to stock. Has anyone had the same good luck as me doing this technique? It also makes it really easy to do the machining of the cylinders.

Thanks in advance,

Arie

[rbaselt]

The clearances shown in the manual are 0.004-0.0012" for piston clearance and 0.006-0.013" for ring end gap. Taper is not mentioned. This is for 250cc engines.

No problem removing cylinder sleeves, I heat the cylinder with a propane torch or by immersion in boiling water and can generally push the liners right out with finger pressure. Sometimes they even fall out (broke one that way once). But I've been told by several knowledgable machinists that boring and other machining operations should only be done with the sleeves installed. Apparently, dimensions can change after installation. --Randall

[heyyou]

Thanks Randall,

I was beginning to think I needed a cyber breath mint. My new shop manual is on the way...... I figured it was about that after looking in my CBX manual - since the bore and stoke are very similar (64.5 x 53 verses 60 x53).

When I was young, my mother wasn't too happy when I'd use her oven to heat up the cylinder casting and drop in the sleeves. I didn't have the best degreasing capabilities back then and it would stink up her kitchen. Thanks mom.....

Arie