KR-1S.co.uk Forum

Hi, just got my engine to bits and noticed the pistons have 'B' stamped on the top of both. I'm just wondering if these are the early type and should be replaced?? How do I tell the difference between the two types??

It looks like the pins are in the piston groove half way down, think I read something on here about it's position being changed???

I do have a new rebuild kit, but now not sure if thats a new type or an early version, (bought it off fleabay, and didn't realise the old pistons were still out there), could be lucky though.

The 'B' is normally a size batch to match up pistons and barrels when new. The older style pistons have radiused ends on the rings that go around the peg and meet on one side.

The later ones have a partially recessed peg that the rings overlap over the top of. That way the peg can't fully fall out because the rings hold it in.

If you can get a photo, I'm sure someone will confirm what you've got.

Tommy