83 XLX Piston Rings

[HypoLuxa]

Hello, I figured I'd deal with oil getting in above the cylinder. I think the front jug is getting oil leaking down from the rocker box. I'm not sure but when I had that rocker box off last year to add the missing front motor mount there was some dried oil pooled up there next to the spring. Maybe that's not where it's coming from. I believe the rear jug has bad piston rings. It otherwise runs pretty good. I feel like it could pull a little harder off a stop. I have not had a plug so fouled it wont run. But I guess I have been changing them often while jetting.

I did a compression test today. Rode bike for 30 minutes. WOT. I get 180 Front/155 Back consistently. If add oil to back jug it brings it up to 180.

Any reason not to do just one set of piston ring?

Any thoughts at all about any of this is appreciated.

I'll do a leak down test tomorrow. Going to wash the bike up and and make sure the lifter rods are adjusted still.

thank you very much.

[farmall]

Any reason not to do just one set of piston ring?

In the old days, extreme poverty and needing a daily driver for Monday after a Friday night teardown.

In 2022, there is every reason to do the trivial amount of labor to pull and inspect both top ends to ensure against surprises if you're gonna pull one. That permits a look at the bottom end too.

[JBinNC]

In the old days, extreme poverty and needing a daily driver for Monday after a Friday night teardown.

In 2022, there is every reason to do the trivial amount of labor to pull and inspect both top ends to ensure against surprises if you're gonna pull one. That permits a look at the bottom end too.

This ^

I have pulled one cylinder to replace a collapsed ring (near zero compression test) on an otherwise healthy motor, but in general it is not good practice, and especially so if you don't know the motor's history.

Ring sets come with rings for both pistons. You must remove the carb and intake manifold to remove one head and cylinder. For both these reasons, no reason not to remove both cylinders.

With the rear cylinder down on compression, it's possible that you will find a galled piston skirt (I know these motors well) and attendant damage to the bore, requiring a rebore and new pistons and rings fitted.

Go ahead and take it apart if you intend to improve it.

Jim

[HypoLuxa]

Yes, I see both your points. After I posted my question it occurred to me the likelihood of it being a simple ring fix not very likely. Prob has scoring on the cylinder wall. Think I'll ride it for the summer and tear it apart early fall.