Dunno, but get it running correctly first. Carbs especially, valves, ignition. Get it all working perfectly. Even burning a ton of oil it will run very well if everything else is right. Ride it a lot. Then see what it does. It may well end up needing rings, maybe new pistons and a rebore, if that's the case you certainly don't want your brand new rings to be run for the first time in an engine with other problems. You want everything to be working right so you can open the throttle and break the rings in correctly. Running a few months with an engine burning oil isn't such a big deal. Well worth it if it allows you to get everything else working right.
I should have said, "It doesn't need rings yet."
Have you determined when its burning the oil? Smoking on acceleration, or on deceleration? Smoke when you first start it up? A lot of the time oil burning is from old hardened valve stem seals. A lot easier and cheaper to fix. If you are not sure about checking the oil level, could it be you have had it to high? This will cause some to blow out while it's running. I bought one bike with the wrong length dipstick, the guy always put too much oil in it. I put the oil level right and the oil burning was fixed.
Also how many kilometers are on the bike? I'm thinking it may be a lot higher over there than it would be on an old 450 around here. Most of the old bikes sold around here, even on thirty year old bikes, have very low mileage. Probably not the case where you live, if it's gone a long way it's more likely to have a lot of wear in there. If it's over 150,000 kilometers or so it's a lot more likely to need some rings. Likewise if it's been raced a lot, or run out of oil, or really overheated.
I should have said, "It doesn't need rings yet."
Have you determined when its burning the oil? Smoking on acceleration, or on deceleration? Smoke when you first start it up? A lot of the time oil burning is from old hardened valve stem seals. A lot easier and cheaper to fix. If you are not sure about checking the oil level, could it be you have had it to high? This will cause some to blow out while it's running. I bought one bike with the wrong length dipstick, the guy always put too much oil in it. I put the oil level right and the oil burning was fixed.
Also how many kilometers are on the bike? I'm thinking it may be a lot higher over there than it would be on an old 450 around here. Most of the old bikes sold around here, even on thirty year old bikes, have very low mileage. Probably not the case where you live, if it's gone a long way it's more likely to have a lot of wear in there. If it's over 150,000 kilometers or so it's a lot more likely to need some rings. Likewise if it's been raced a lot, or run out of oil, or really overheated.