Topic: Rebuild=re-ring?

[nitrofish1]

Now that I got my engine fully disassembled, is it better to re-ring the pistons? Or to use the ones it came with since they are already broken in?

[iron_worker]

Re-ring would be better. It might help to restore some compression. However if the bores are worn out too much then re-bore and new pistons & rings would be the proper way to go.

IW

[nitrofish1]

I have yet to take any measurements on the clearances as such, need to go borrow a set of gauges so I can do that. The bores and rings seemed like they were in good shape to me while I was disassembling them.

[Bailgang]

Assuming the bores are within spec then I would definitely re-ring it since it's already apart, you'll thank yourself later for doing it.

[Goofaroo]

When I disassembled my 72 500 with 19K, the bores, pistons, and rings were in excellent shape and the ring gaps measured out perfectly.  I just cleaned everything up, polished the tops of the pistons, gave the cylinders a light hone, and put it all back in it's original cylinder and orientation.

If you are going to replace them, I would certainly use Honda rings.   

[cougar]

nitro ; When you measure the bores even if they are within specs, go ahead and rering it ! But 2 things, 1st if there is ANY lip around the top of your cylinder go to your local parts house and borrow/rent a "Ridge Reamer" and carefully remove any trace of that lip. 2nd then borrow/rent a "Ball Hone" and put a nice crosshatch up and down your cylinders. The reason for what I've told you are as follows, 1st- If you don't remove that lip and you install New rings you stand a good chance of busting your top ring or worse because the new ring will have a square edge on it and that lip won't so when your new ring hits the lip (OUCH) ! 2nd- putting a nice crosshatch up and down your cylinders will aid Greatly in seating in your new rings. And although a lot of folks may not agree with this, I recently read an article about breaking in engines that made a lot of since to me ! I'm 51 and have built quite a few engines in my time but read the article and decide for yourself. It's located here, http://www.mototuneusa.com/break_in_secrets.htm  . He also has a number of athor articles that I've yet to read, but since I have to use "Dial-Up" out here in the country every thing moves at a snails pace,LOL ! Take care !   ...cougar...

[70CB750]

I just went through it with the F engine.  It had a broken ring - I replaced them all.

here is a good discussion - dont let the title scare you:

http://forums.sohc4.net/index.php?topic=64025.0

I bought my flex hone (2.5", 320 grit)  on ebay for $30 or so, I could find only one in local stores and it was 4.5 inches.  Flex hones used to be everywhere,  but seems like the times have changed.

I used cordless drill and 30 weight oil and it worked like a charm, but my jugs were low miles too:

http://forums.sohc4.net/index.php?topic=115305.50