Piston Rings

[petermigreen]

Rather clumsily managed to break a ring during disassembly today. So obviously need to get a new set.
Question is this. Am I correct in thinking that if cylinders are on standard bore then the pistons will have NO numbers on the top surface?
Anybody got any sets?

Thanks, Peter.

[Bryanj]

Pistons are not always marked with the size but the rings always are by the gaps usually with a letter on one side of the gap and numbers on the other. If no numbers its standard then 25, 50, 75 or 1.00.

Numbers/letters always face upwards

[petermigreen]

Very helpful thanks, I'll clean them up and have a closer look, under a magnifying glass.

[petermigreen]

Just an 'R' on middle ring. No markings on top rings does that mean they are non directional?
Thanks
Peter

[Trigger]

Should be markings on the top ring, where did you get them from ?

[petermigreen]

they came in the engine. I was under the impression they are the original rings. Maybe not.
Peter

[Trigger]

Sorry, I assumed that you had broken a new ring. Fitting old rings is a false economy in my book, you will have to cross hatch the bores to get new rings to bed in.

[Bryanj]

If they have been in a while there can be enough wear on the side to remove any light marking. R is a common one with nothing else means standard

[Seabeowner]

Peter, I could not work on bikes without 6""digital calipers. They are pretty cheap, but maybe avoid the £5.99 variety. £20 would do it. Measure the max dia. of the piston skirt and even after a considerable mileage that should still be pretty close to the bore size.