What should I be looking for in a piston set - .25 over or 1 MM over (I know, matching ring set, too)?
I guess what I'm asking for is a lesson in Honda piston overbore sizes.
Thanks, fellas!
What a concept - A Girl Bringing Back Her 1966 Super Hawk
Hi,
If your cylinders are standard bore (60mm) to begin with, and don't have any deep pitting or scoring, 0.25 oversize should be okay. OE Honda and aftermarket companies made pistons and ring sets in 4 oversizes. 0.25mm (S1), 0.5mm (S2), 0.75mm (S3) and 1mm (S4). If you have a local machinist have him measure it in its current state and see what he thinks. I would hate for you to buy a piston/ring set size you don't need. HT
Thank you, Tom! 1965 CB77 305 Super Hawk
1989 NT650 Hawk GT 1981 Yamaha XJ550 Seca
I read the entire saga of Ugly Betty this afternoon. That was a beautifully documented, well written, well photographed piece of history. I really learned a lot from it, and I was oh so impressed (again!) at how beautiful the bike turned out, as well as how much her owner loves (ed) her. The amount of talent and help on this board was reinforced by that story, as well. I think I'm in good hands here!
Last edited by sarals on Tue Jul 10, 2012 9:41 am, edited 1 time in total.
1965 CB77 305 Super Hawk
1989 NT650 Hawk GT 1981 Yamaha XJ550 Seca
I found an excellent cam chain tensioner for a realistic price on eBay yesterday, and it's now on the way. I've been looking at pistons and rings, and the prices out there are O U T R A G E O U S!!!! Those pieces cost $12.00 new! Can you say "gouge", boys and girls?
I have a caliper, and I'm going to try to measure the bores in my barrel today. I'll have a good look at the liners, too, along with getting some hi-res shots to put here for comment. I do plan to take it to an automotive machine shop to have it inspected. A "bike shop friend" told me a long time ago the ideal thing to do when the top end is pulled apart on an engine is to do a "break away hone" and replace the pistons and rings. The next best is the hone with new rings, leaving the pistons. I know I shouldn't think this way, but with the silly prices out there, I'm almost forced to be toying with this idea; if the liners are okay - of having them honed, and reusing my good piston with new rings. The seized piston is junk, obviously, and I'd replace it with a known good used one with new rings. New circlips are a must, no matter what. If the liners need to be bored, well then, I have no choice - it's new pistons, rings, circlips and probably wrist pins. Please tell me how stupid I am to think this way! On another front, I think it's becoming more and more obvious that I need to split the cases. I've read too much about transmission woes here, and LM was concerned that my engine had been running with dirty oil. My bike ALWAYS shifted well, never an issue, and my main stumbling block is "if it ain't broke, don't fix it" - that I could eff up the transmission if I go digging around in there. Then again, the internals will need cleaning. What was to be a "rolling restoration" is becoming more and more a complete restoration, and the time frame is growing exponentially. I've heard that happens! Like remodeling a kitchen.... 1965 CB77 305 Super Hawk
1989 NT650 Hawk GT 1981 Yamaha XJ550 Seca Hi
Depending on what size you need to bore the liners to, I may be able to help with some used but pretty nice pistons. I have a pile of 305 barrels that I am working through as part of my projects. I don't think that you should reuse the ones that have seized. I definitely have a nice plus 0.5mm pair. Postage from UK might be tricky but I am in the US on vacation in August so may be able to fix that too. Keep in touch. Graham '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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