KZ750 CSR Valve Guide Oil Seal Failure

Education time....

It's a twin cylinder so you have 4 guides. They are probably OEM cast iron guides. If the bike is low mileage they're probably just fine.

If they did need replacing then the setas will have to be cut. Depending on the skills of the person installing the guides and the previous wear, the seats may need just a touch up or significant cutting. It all depends...

After the seats are cut the installed height of the valves need to be set. This is commonly called "tipping". That is where most auto machine shops fuck things up...

In your service manual is a spec for the installed height. The procedure for measuring it is a little tricky if all you have are vernier calipers. You can poke them down in there three times and come up with three different measurements.....follow this procedure.

Have them measure your installed heights BEFORE they do any cutting of the seats. If they accurately measure that spec they can then match it after the seats are cut and you won't be in the middle of nowhere with your shims.....

I'm not sure what that twin calls for but the 900/1000 &1100 spec is 1.475" to put you in the middle of the shim adjustment range.

Now...start from the start on your situation....

I read your compression was 165 lbs in both holes. Pretty good.

Unless the cylinder that seemed to quit running had an oil fouled spark plug, then I doubt the valve seals had anything to do with the problem. Check the basics before you dive into the motor. Did the plug cap take a dive on you? Is the plug wire corroded where the cap screws on to it? Is there crap in the carb for that cylinder? Is the intake boot leaking?....etc.etc. etc.

ALWAYS check the basics before you tear a motor apart that had good compression...

In addition to the 165 psi compression, he says this

On the way back it starts leaking oil out of the exhaust just like it did when the valve guides did last time they went.

I don't see any way a leaking valve seal could do that, not even a missing valve seal, so my thought is maybe a cracked valve guide, maybe a cracked head, or possibly a porous head casting. I have an 82 CSR motor with a porous block, it connected the main oil gallery to the outside, so I know Kawasaki had some casting problems on the 750 twins in that year.

The only time I have seen oil running out the exhaust is with a holed piston.

.

LarryC, thanks for your information. As steell said, I have checked into this before and it is definitely something non-electrical because I actually just replaced the coil and checked all the connections in the ignition system prior. Also, there is the case with the oil leaking out the exhaust. It was also quite a large amount of oil too. Enough to drip down all over the side of the bike, soak my pants and boots.

Steell, thats what I'm really looking for. A leaky valve seal is the only thing I could think of because its something I just replaced and I believe the piston/rings are in good shape. What are you saying about a porous casting? I understand casting methods and such and I understand how that could be an issue but how could something like this show up after ~16000 miles? Would the cracked head be something easy to spot or are we talking about a microcrack? Would a new head be the best way out of this situation that seems to be going more and more to shit as time progresses?

steell wrote: In addition to the 165 psi compression, he says this

On the way back it starts leaking oil out of the exhaust just like it did when the valve guides did last time they went.

I don't see any way a leaking valve seal could do that, not even a missing valve seal, so my thought is maybe a cracked valve guide, maybe a cracked head, or possibly a porous head casting. I have an 82 CSR motor with a porous block, it connected the main oil gallery to the outside, so I know Kawasaki had some casting problems on the 750 twins in that year.

The only time I have seen oil running out the exhaust is with a holed piston.

.

Didn't see that....could be a loose guide but even if it had NO seal it wouldn't do that.

Could well be. We had to replace blocks on J motors as well because they were porous. There were some strange issues with early 80's Kawasaki engines sometimes.

Look at all the old Chevy V8's with those shitty umbrella seals

Are you talking the actual block being porous or the head? What part being porous would normally be at fault?

If the header pipes are correctly installed with new gaskets, oil blown from the combustion chambers through the exhaust ports would not escape onto the engine cooling fins.

Is it for certain that the oil leakage isn't through a faulty tach drive seal?

Good Fortune!

The header pipes are properly installed but I bet the seal isnt 100% because I had to adjust them once I had them on most likely messing up the gasket a little bit. I did feel around the seal when then engine was running and I did not feel any airflow leaking through.

And I actually had that problem fixed a few days ago. Its nothing a few home depot faucet washers cant fix hehe