KZ305 Top end work. Where to get parts?

The bike needs oil added every other tank of gas. Also oil is leaking from the head gasket.
I already have a top end gasket set, but have not found a source for piston rings. Depending what I find once all is dissembled, may need pistons, or over size pistons and rings.
I don't want to get stuck not being able to find parts once I have it apart. My searches haven't come up with these things.

www.cmsnl.com/kawasaki-kz305a1-csr-1981-...partslist/64150.html

EDIT: Also this - https://www.[ebay].com/itm/385079982913

It looks like standard rings are readily available. The 305 was a comparatively low-production-volume bike, so oversize pistons and rings may be harder to find.

Forgot to ask: do you know you're burning oil that's getting past the rings? Is there blue smoke in the exhaust?

If so, you might be burning oil due to bad valve stem seals. I would look at them first, rather than rings, unless the bike has 50K+ miles (or has been abused). Viton seals are readily available.

Exhaust does not smoke. Oil is leaking around the head gasket,so it needs replacing. While I have the head off, I feel I should check cylinders, pistons, and rings. The gasket kit comes with valve seals, so they will get replaced. Since it is looking like I will not be able to source oversize pistons/rings, I'll keep my fingers crossed that everything is fine in that department.

Ron Ayers? Partzilla. Pick yer poison!

If the exhaust doesn't smoke (excessively), I personally wouldn't worry about new rings/pistons unless there was something clearly wrong once the head is off. I'd suggest checking the bores for wear but otherwise leave everything below the head unless you're having other problems. If you are planning on checking pistons, be sure to get a new base gasket too. Chances are it's fine, and someone has just done a poor job installing the head gasket and the oil is all leaking, not burning. You can't tell for sure until you fix the leaks.

Once the head is off, don't forget to check that the head surface is flat, and that the deck is flat too.

I've always ordered from Partzilla, they've been pretty good for me.

I don't remember my 305 smoking excessively when I rebuilt it because of a bad head gasket, but I found a scored piston once I got in there. And yer right, there are no oversized pistons or oversized rings available for reasonable prices, when they're available at all, which is very rare. I've been looking for a year. I've also looked for good cylinders that don't need boring, but those are equally unavailable. I had to order from Germany to replace my stock piston.

Someone in Canada sells 61mm rings for it. They should be on ebay. I bought some when I did mine. Everything else is also findable, as long as your pistons and bores are good

Edit: the rings are still on ebay but maybe ebay links aren't allowed. I tried posting it and it's invisible.

Yes, I ordered the gasket kit from that Canada seller. I still ride this bike almost daily, so I will be waiting until this winter to tear down the engine. I'll keep my fingers crossed that I woun't need over size pistons/rings. 

Wish I could ride mine at all...

I have a belt I'll sell for a good price if you need a spare, if you have a belt drive. If so PM me

Thanks, but I have chain drive.