Replacing one piston ring?

Here's the problem. Took my nice set of new 70.25mm pistons and rings to the machine shop for the proposed Hone. Just got a call to say he's broken one of the bottom (oil control?)rings!

The bottom rings on these particular pistons are one piece.

If I can locate a 1 piece repacement of exactly the same dimensions, which he tells me are for the 70.25mm bore and are 2.54mm tall, even though it may "look" different, should I use this replacement ring? Could this present problems? different weight? different tension?

Thanks.

I don't think you would have a problem. Most of the new oil scraper rings are three piece. Even if you had to use one of those you should be fine.

If these are the bottom rings, they are three piece scraper rings... I have broken a few of these installing the cylinder... it is easy to do as the top and bottom ring parts that sandwich the oil scraper, are very thin and can hang between the liner and piston and get smooshed when you install the block. I also have about a zillion of these and they are not critical if they are used. They don't wear much and there is no end gap measurement or wear. I don't know if your pistons are standard or overbore but someone is likely to have the piece you need so you don't have to buy an entire new ring set for the piston. All my spares are for stock 903cc (66mm)...

George, the early versions of these rings have 1-piece cast oil rings - fairly brittle (probably why Kawasaki switched).

I don't think it would impact performance to replace the oil ring with another one - either 1-piece or 3-piece.

The ring you need is a Honda CB450 twin / first over. Good luck finding that.

Jay

Jay,

Thanks for the CB450 1st over direction. "good luck finding that"...doesn't sound good! Any idea of the correct year?

Thanks.

This is a no brainer.
If they broke one , they fix it.
With a MATCHED proper set of oil rings.

AND get it in writing that they had a problem.

If they are a business and you are paying them and they broke the ring , they owe you that much.

Its just the cost of doing business....sometimes you have to eat it.

They replaced the broken ring with a 3 piece of the corrct size.

In the mean time, I managed to contact the guy in Australia and he had a correct spare which he sent me absolutely free.

And to think of all those bad things we say about the Aussies! Very nice guy (ozzyozzyozzy75).

Thanks again everyones help with this one.