Compression question PEASE HELP: KZ1000 E 1980

Just my 2 cents.. If an engine that has been sitting is fired up and smokes untill it warms up, generally, it has bad valve stem sealing. guides, seals, both. While the bike is sitting, oil seeps past the guides and pools behind the valves and as they open, into the combustion chamber causing the smoke on starting. If an engine smokes on acceleration/ deceleration once warm, it is most likely a ring sealing issue. Overly worn rings, glazed walls, broken ring or worn sleeves. oil is pulled up and pushed down past the oil control rings and into the combustion chamber. the crank case is pressurized by the "blow by" and this also causes oil to be places where it does not belong. I think that your engine is simply wearing out. It's very likely that it can be honed, re ringed, and that a valve job would help it out. This can be done by a novice. I think it's what you need.

Zero, do you have a part number for the Kawasaki tool?
I have shim under bucket, so I don't need one.

I missed that, koolaid. The shim tool is for shim over bucket. I work almost exclusively on them. Are you SURE you're shim under bucket? A 1980 should be shim over and the kawasaki tool is:#57001-113. you can find copies on Ebay. They're still easier to use and much better than the K&L. If you have a 1980 KZ1000 and its shim under, someone has been in there and you may have some performance parts. ??? (I just saw that you have a G.P,Z.750..nevermind. sorry) Also, Z1 enterprises actually sells the knock off Kawasaki tool.

I'm not the OP, I've just been working with him up to that point, then I told him to pose the question in his thread,which you answered but did not give him a part number.

ZERO wrote: I missed that, koolaid. The shim tool is for shim over bucket. I work almost exclusively on them. Are you SURE you're shim under bucket? A 1980 should be shim over and the kawasaki tool is:#57001-113. you can find copies on Ebay. They're still easier to use and much better than the K&L. If you have a 1980 KZ1000 and its shim under, someone has been in there and you may have some performance parts. ??? (I just saw that you have a G.P,Z.750..nevermind. sorry) Also, Z1 enterprises actually sells the knock off Kawasaki tool.

Yes my 80 KZ1000 is the shim over and I bought that same tool off of Ebay. It works great.

Will that tool work on a '79 750 twin? Part number is different.

650ed wrote:

Flatblackobsession wrote: Right-- very baffling. So, the question would then be: how much of a compression increase (i.e. "drastic" compression increase) indicates oil action on the rings, as opposed to displacement? A hell of a mystery.

I also put a little more than a teaspoon in there-- maybe 15-20 milliliters, but it was the same amount in each cylinder, so it makes me wonder if that isn't why there was this uniform psi increase-- regardless of base cylinder readings.

Any and all thoughts on experiences/theories are appreciated. I really want to get to the bottom of this.
Thanks,

That seems very logical to me. I would think that if all the rings are holding compression well, the same volume of oil added to each cylinder should result in the same increase in compression readings. I would try a leak-down test to see if you can detect compression leaking from the exhaust or intake valves, or if it's leaking past the rings into the crankcase. Ed

You are absolutely correct, oil added reduces the combustion chamber volume, increasing compression.

If the rings are bad and you add oil, you will see at least 50 psi increase, the most I've ever seen was 140 psi increase.

Sorry, Topper. Can't say for sure. I know that the cheapy K&L tool fits the 750 twin, but the Kawasaki part clamps onto the head and holds the edge of the shim bucket and the shape of the head is critical.It's very likely that the Kawi tool will not work, but also likely that another tool exists from them. Ages ago, when I was a KAWASAKI tech, we had tools that absolutely NO-ONE knew what they were for.... :laugh:

Topper wrote: Will that tool work on a '79 750 twin? Part number is different.

Thanks-- I appreciate the thoughts on that. I've debated this a lot myself and did the compression check, then added oil to the cylinders-- no substantial PSI increase, suggesting rings are fine. Is there a way I can check for blowby as another way of checking this?

Thanks-- I really appreciate the thoughts on that-- been hard to pin down just how much PSI is supposed to increase if rings are not sealing.

Flatblackobsession wrote: Thanks-- I appreciate the thoughts on that. I've debated this a lot myself and did the compression check, then added oil to the cylinders-- no substantial PSI increase, suggesting rings are fine. Is there a way I can check for blowby as another way of checking this?

Yes. A leakdown test should show if compression is leaking part the rings. If when air pressure is applied to the cylinders you discover air escaping form the oil filler cap (when open) or from the crankcase breather the air is leaking past the rings. Ed

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. Or just use a portable compressed air tank.

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).

Good Fortune!