oversized rings?

[Bob Shaw]

I did a leak down test on my 82 GS850G. Number three cylinder didn't pass. Compression test wet indicated rings not so much valves. I'll lap them in anyway. I took the head and jugs off and am in the process of honing out the cylinders. I'm already past the limit for cylinder bore before honing. How do I determine what size rings to install and what sizes do they come in. I know cars are 10,20,30,40,60k oversized, but what about bikes? Any help is appreciated.

[JTGS850GL]

Assuming you know this but making sure: You have to change out the pistons and rings as a set and you really should do it across the bank. As opposed to just one cylinder. As for what size, the only one I know currently available as OEM is a 1mm overbore. Other option may be available as aftermarket. Might be easier to pick up a cylinder bank and replace that with your pistons and new rings.

[Nessism]

I agree, look for a low mileage stock cylinder and then use new rings.

[tkent02]

I have a few 850 cylinders.

[Bob Shaw]

Thanks for your help. I'll look into another cylinder head...

[tkent02]

Head or cylinder?

[JTGS850GL]

You don't need a new head. You need the cylinder bank only.

[Bob Shaw]

What is the cylinder bank?

[JTGS850GL]

What is the cylinder bank?

It's the part that the pistons ride in. Just above the engine case. Item number 1 in this pic:

[Bob Shaw]

OK, Thanks. I never heard that term used before. I just referred to that as the cylinder head.

[JTGS850GL]

OK, Thanks. I never heard that term used before. I just referred to that as the cylinder head.

The cylinder head is what goes on top. It's the part that contains the valves, cams, intake and exhaust ports.