Topic: Pistons

[MILO]

Hi,

I've started the disassembly of my cb550 engine, so far I've taken all the top end apart, and will take the head to my local head works place to get it fixed up.
I've got some pictures of the number 1 piston, all the pistons look the same and have no physical scoring on them, just discoloration.


What do you guys think,Still usable?
The plan was to hone the cylinders and change the rings if they are still good to use.

[Terry in Australia]

G'Day Liam, where are you in Melbourne? Your pistons may still be worn past useable limits, you'll need to measure the clearances between each piston and the cylinder bore to determine whether you'll get away with a set of rings, or whether you'll need a rebore and new oversize pistons. Cheers, Terry.

[bryanj]

Looks like a bit of blowby but that is not terminal, as Teryy sez you need some accurate measuring done

[scottly]

That piston doesn't look too bad, but, as Terry has suggested, measure it. I have re-ringed worse looking pistons in a pinch before..

[MILO]

I'm in Murrumbeena, which is around Carnegie or Oakliegh sort of way.

The big line on the piston in the picture is a piece of string, not a scratch, just saw it then and had to check the piston again! haha
The rings look alright too, not that ive got anywhere near enough experience to tell if they are or aren't lol

Using my little digital verniers i got
-58.42mm for the top of the bore
-58.51mm for about the middle of the skirt
-58.08mm for the top land bit or whatever its called

[dave500]

the rings havent bedded in correctly on that motor,and its been lugged in too high a gear.,you might get by with new pistons in the old bore once honed.