smokey 83 KZ550 M1

I have a 1983 kz550 M1 with a little over 30k miles and it smokes like crazy! I'd say after about 100 miles I have to put about a quarter of a quart of oil in her just to top off. My question is, with this many miles and that much burning am I looking at just valve adjustments or an entire rebuild? Or maybe new piston rings? Thanks in advance for the help.

That's very low mileage to need a rebuild unless oil changes were neglected sometime in the bike's past. I doubt that valve adjustment will have any effect on the problem. Some more info might help narrow down the possibilities. Did this problem just start happening, or did the oil consumption/smoke gradually build up to the current level? How often have you been riding the bike; did it sit for a long time without being run? Has it smoked since you first bought it; how long ago was that; how many miles have you personally put on the bike?

One thing you can do to help pinpoint the source of the problem is a leakdown test. This should help identify if the problem is with the rings or valve area. Ed

Would also do a quick sniff-test of the crankcase oil to detect possible gasoline contamination that might be diluting the oil and causing it to burn out the exhaust.

Such contamination may result from by leaking carb fuel valve accompanied by obstructed carb overflow circuit.

Good Fortune!

Thanks for the quick replies! I have owned the bike for 4 years or so and the smoke has gotten worse over the couple thousand miles I've put on it. The bike hasn't Sat for more than a season and was driven regularly when I bought it. It started missing on at least one of the cylinders when I put it up last year. I chalked this up to fouled plugs and the smoke. I just realized after taking the valve cover off that one of the bolt holes on the first cam cap is stripped and was held in with loctite. Could this cause some issues with the valve and cause smoke? I plan on using a timesert kit to correct the problem.

Definitely do a leak down test. That will tell you if the problem is with the valves, rings, or both. Ed

Thank you 650ed I will do a leak down test. I have recently discovered another cam cap bolt hole that is stripped so i will fix both of those before the test. For give my ignorance but, I oddly enough, can not find any material on leak down testing on this site. I would appreicate it very much if someone could point me in the correct direction.

Take a look near the bottom of the page in the link below. It gives a leak down test description. Ed

kzrider.com/forum/13-bike-related/570322...hame?start=40#572221

shaftDKZ wrote: ... will do a leak down test...if someone could point me in the correct direction.

A leak-down test injects air pressure through the spark plug hole to pressurize the combustion chamber.

Can perform a poor man's leak down test by introducing compressed air into a spark plug hole and listening to where it escapes from the combustion clamber. This may be done at TDC or any other cam positions where both valves are fully closed. Top dead center (TDC) is when the piston is at its highest position. An easy way to tell TDC is by alignment of the T mark with the case mark when viewed through the timing window.

May introduce a spurt of compressed air by using a rubber cone-tip blow gun (rubber air nozzle) held into the spark plug hole. And of course keep holding it in position to keep air from coming back out the spark plug hole while listening for escaping air at other places. The air compressor should not be running while listening because the noise will likely drown out any sound of escaping air.

A portable compressed air tank may also be used in lieu of a live compressor.

Air heard escaping from exhaust port indicates exhaust valve not fully closing (perhaps too tight clearance or damaged valve or valve seat).

Air heard escaping from carb intake indicates intake valve not fully closing (perhaps too tight clearance or damaged valve or valve seat).

Air heard escaping from crankcase breather indicates loss of compression past rings into crankcase (perhaps worn piston rings or cylinders).

Air heard escaping from head gasket area indicates indicates loss of compression past head gasket (perhaps due to a blown head gasket).

A leaking valve may sometimes be resolved by adjusting the clearance to within specs.

A leaking head gasket may sometimes be resolved by torquing the head fasteners when the engine is stone cold (such as after sitting overnight).

As the test relates to the leaking down of compression (i.e., rate of compression loss from within the combustion chamber), the leak down test won't help much toward specifically diagnosing or detecting a mal-functioning oil ring.

Of course, where the leak down test indicates worn compression rings and/or worn cylinder bore, it could also be presumed that the oil ring might also be worn.

However, the leak down test may pass with flying colors, even with a broken or mis-fitted or otherwise mal-functioning oil ring, with heavy smoke from the exhaust.

Same with a standard compression test, which may show compression within specs, despite existence of a broken or mis-fitted or otherwise mal-functioning oil ring, with heavy smoke from the exhaust.

If a standard compression test produces low figures, it may be due to worn rings/cylinder and/or incomplete seal when valve is supposedly closed.

Adding a teaspoon of oil into the cylinder through the spark plug hole, and re-testing, will usually produce slightly higher or significantly higher figures.
If only slightly higher, or no higher, the compression is probably being lost through a poorly sealing valve.
If significantly higher, the compression is probably being lost past worn "compression" rings and/or worn cylinder walls.
This is because the teaspoon of added oil is helping prevent compression from being lost past worn "compression" rings and/or worn cylinder walls. But the the teaspoon of added oil doesn't help close a poorly seating valve.

In the case at hand, if testing indicates acceptable compression figures, a broken or mis-fitted or otherwise mal-functioning oil ring may nevertheless cause heavy smoking from the exhaust.

Other possibilities besides a mal-functioning oil ring that could cause heavy smoking from the exhaust might also include such things as bad valve stem seals with worn valve guides, or gasoline-contaminated oil, or over-heating for whatever reason, etc.

Good Fortune!

All of this is extremely useful info. Thanks so much and I will let you know how it turns out.