no more guesses - can't figure it out

dnpurdy wrote:

I put my hand over the open #2 hole as it was running just to feel and I got a hand COATED with oil.

I smelled it to make sure and definitely no gas smell and definitely oily smelling. My hand felt EXACTLY like after you've eaten a tub of movie theatre popcorn with butter...

I'm going to go zip it all up and take #4 out and see if I get the same feel from it.

With these leakdown and compression numbers, where is this oil coming from???!!!????

A blown valve guide seal will leak some oil into the cylinder, I had one leaking so bad it fouled the plug every day. The seal had disintegrated.

I would be surprised if a valve seal leaked enough to put a steady stream of white smoke out the back (mine didn't). They usually just put out a lttle smoke on start up and it clears right away.

My other guess might be a collapsed (broken) oil ring. If the compression rings were reasonably good, you would still get good compression but the collapsed oil ring would dump oil into the cylinder.

BTW, this symptom was reported by somebody who had rebuilt their engine and cracked an oil ring going together but did not realize it.... until he fired it up and saw the stream of white smoke out the pipe.

EDIT: just noticed somebody else already suggested this answer, I still think it is correct.

My other guess might be a collapsed (broken) oil ring. If the compression rings were reasonably good, you would still get good compression but the collapsed oil ring would dump oil into the cylinder.

That is my guess as well, so that makes at least three so far

If you can find someone that has a really good bore scope (one of the models costing well over $1000), you could run #2 down to bottom dead center and look for small scratches (would look like lines) at the bottom of the cylinder on the walls. A lack of scratches does not mean that everything is ok with the oil ring, but the appearance of scratches would mean that everything is definitely not ok with the rings.

Alright, it looks like a bad oil ring.

A week from now I have a 6-week sabbatical so working on the engine is not such a bad thing.

If I'm going to have to take the head and jugs off, why not do the wiseco 810?

Additionally, if I'm going to do that, why don't I take the oil pan off as well and service the starter motor clutch.

and if I'm going to do that, why not take the engine off the bike and change the primary chain and cam chain !!!

seriously though, if i need to change the oil ring, and I want to keep the bike for a long time, is it worth while to do the wiseco 810?

dnpurdy wrote:

seriously though, if i need to change the oil ring, and I want to keep the bike for a long time, is it worth while to do the wiseco 810?

Your call, if the extra $$$ is justified by the extra power.

I'm just thinking if i do the 810 kit, I don't need to worry about measuring overbore sizes and all that. I can be sure that the pistons/rings will be a perfect fit.

Back to being flack bait -- With good compression and other components already checking out so nicely, may suffice to just replace the one bad oil ring and re-assemble (with new head and base gaskets). Especially if cylinder bores are within specs.

Could preserve the no-slouch stock KZ750 Spectre in its comfortable run-forever cruiser role, and apply saved hop-up money toward adding to the stable another larger Kaw or already-breathed-on KZ750.

Just thoughts.

Good Luck, in any direction!

Alright, having never gone this far into an engine before, what should I do?

After I take off the head, I can measure the bore for spec with dial caliper, right?

Should I test all 4 or just the 1?

If I'm going to take the cylinder block off, should I replace all 4 ring sets, or can I get away with just the 1 there as well?

Would follow FSM procedures to measure cylinder bores with a "T" Bore Gauge to assure being in specs (as likely are, given the good even compression test figures). But if marginal or beyond specs, then consider re-bore.

Am thinking about feasibility of replacing only the one oil ring on #2 piston. With no honing. And leaving everything else as is (except head and base gaskets). But am uncertain and urge awaiting more confident advice.

Should closely follow FSM procedures, including those on removing and replacing cylinder block.

Good Luck!

It takes a minimum of a T-bar gauge and a 2"-3" micrometer, or a dial/digital bore gauge, to measure the cylinders. Don't even think about using a T-bar gauge and a dial/digital/vernier caliper, it's a waste of time as the accuracy is not there.

You might give Z1 Enterprises a call (after looking up the Kawasaki part number on Kawasaki.com) to see if standard size rings are still available (if that is the problem).

Or (if you are as cheap as me), if you want to try a used oil ring, I probably have several you can have.

If you decide to go the 810 route, APE probably has the best deal around for a kit/bore combo, I think it's only $90 to bore the cylinders if you buy the kit from APE.

Here's the part number for the standard rings, 13008-5046, and they are the same as the 83-85 GPz750 rings, but I'm pretty sure I have a used set of those also.

As far as I know, NOS GPz750 rings have shown up on eBay exactly twice in the last three years (and I bought both sets), so I wouldn't count on finding any on eBay

problem solved...

it seems my bike was stolen last night.

Patton wrote:

Back to being flack bait -- With good compression and other components already checking out so nicely, may suffice to just replace the one bad oil ring and re-assemble (with new head and base gaskets). Especially if cylinder bores are within specs.

Could preserve the no-slouch stock KZ750 Spectre in its comfortable run-forever cruiser role, and apply saved hop-up money toward adding to the stable another larger Kaw or already-breathed-on KZ750.

Just thoughts.

Good Luck, in any direction!

I was thinking similar thoughts, except that if I was going to do that much work I would run a hone down the cylinders and install all new rings. If one broke, I would want to replace them all.

dnpurdy wrote:

Alright, having never gone this far into an engine before, what should I do?

After I take off the head, I can measure the bore for spec with dial caliper, right?

Should I test all 4 or just the 1?

If I'm going to take the cylinder block off, should I replace all 4 ring sets, or can I get away with just the 1 there as well?

Not sure what they cost. I'd replace all rings just because they are not supposed to break so I would suspect the ones in there had been abused. It's a ton of work to do the job, so I would want to cut my wrists if I did all that work and another old ring broke in a couple of months.