GPz550 #3 Rod Knock Probable Cause

I've posted this on www.gpz550.com as well.

Well I finally gutted the engine that a little over 3.5 years ago. I had to stop riding the bike, due to a knocking sound heard at any rpm above idle. Got the bike with 38,000 on the odometer, and close to 6,000 miles later, and way more oil and filter changes than I should have(with motorcycle-specific oil, we won't get into that topic, no-no-no), it started one very warm summer day. Since then, I've put the bike in storage, and 2 years later, it still made the noise. Changed the engine with another, and haven't got into the noisy engine till now. #3 rod moves up and down on the rod journal, and the others don't. I removed the head, and cylinders, sent them to APE for rebuilding and opening up for their 615cc kit. Got everything back ready to install, and that was 2 years ago. I look at the parts and make "Veroom-Vroom" sounds. The plans are to do a complete rebuild of the bottom end before the 615cc kit and rebuilt head goes in. Taking no chances.

#3 Bearing Failure seems to be common from something to do with the oil clearances on these engines. It's what I've heard, and maybe someone can tell me if it's a "old wives tale" or reality.

Anyway, I've split the cases, and removed the rods from the crank. and I think I've discovered why #3 failed. See the pictures below, and fire away with the thoughts. Should be easy for some, and an awakening for others.

L - R is #1 - #4





You can see #3 Rod Bearing is obviously darker than the others, but looking closer . . .


#1 and #2 Rod bearings


#3 and #4 Rod Bearings

To my knowledge this engine has not been apart, and what you see is what came out of the engine from the factory.


Let me know what you think.

CoreyClough wrote:

I've posted this on www.gpz550.com as well.

Well I finally gutted the engine that a little over 3.5 years ago. I had to stop riding the bike, due to a knocking sound heard at any rpm above idle. Got the bike with 38,000 on the odometer, and close to 6,000 miles later, and way more oil and filter changes than I should have(with motorcycle-specific oil, we won't get into that topic, no-no-no), it started one very warm summer day. Since then, I've put the bike in storage, and 2 years later, it still made the noise. Changed the engine with another, and haven't got into the noisy engine till now. #3 rod moves up and down on the rod journal, and the others don't.

There's the knock.

Any of the previous owners fond of doing wheelies?

Something starved the oil to that bearing.

I knew it was rod knock, but didn't know it was a spun bearing. I guess I didn't make that whole post clear. No damage, but #3 Rod Bearing is spun, causing the noise. Rod is OK, and rod journal is OK, but the bearing is toast.

There, that might help.

There are no "ears" on #3 bearings.

kpier998 wrote:

There are no "ears" on #3 bearings.

And "X" gets the square ! ! !

This is exactly what I'm thinking. Why would there be "ears" on all the other rod bearings and crank bearings, and not have any on #3? I've looked on the back side to see if just maybe they were sheared off, but no sign of them.

Has anyone seen this before on maybe another size/year Kawasaki Engine?

The "ear" commonly referred to as the tang is to keep the bearing from turning in the rod. However, if the bearing starts to seize on the crank, it can still turn the bearing ion the rod and flatten the tang down. It will still be there, but flattened.

Is that what yours look like Corey?

Jay

I have some pictures downloading and will post them here, when they're ready.

I can barely pick out some type of tang there, but nothing like the other ones that have them still. Could be the case Jay. :S

Hey, the turkey is done!!! :woohoo:

These are pictures of #3 Rod Bearings only.







The Good, The bad, and The Ugly below:



So, any word on hearing about a cure for this tale of #3 land it's lack of oil or is it a farse. The rod journals on the crank all measure 1.296" (32.918 mm), and the main bearing surfaces on the crank measure 1.258" (31.953mm) so standard bearings should bbe used after a light emory cloth cleaning of the surfaces, right?

Anything that can be done to increase oil flow to these surfaces?

I can take pictures of the crank and rods too.

Hope someone learns from this, somewhere in the future.

There is no way that the rod and the crank do not have some damage to them, the rod really needs to be checked on a special dial indicator, I am sure you will find its out of round, and if you do not resize it, and I am not sure this is recomended for a motorcycle rod or not, best to replace the rod, and I would have the others checked as well.
Also the crank is going to be out of round needs to be replaced,

You have spent a lot of money, do a little more and make it right

...even if the rod bearing only spun on the journal? There is up and down play. I can see if the bearing had ripped apart, then out of round might take place, but I'll have the crank and rods checked just to make sure. Better to find out now when all is apart, than just after I start it up. :blink: Just a few more pieces to send to APE.

Now this is a stock GPz550 Engine, unlike the other thread about the Big Bore 615 Engine.

If I recall correctly (and I'm not sure I do), the GPz900 and early ZX9's were noted for spinning #3 rod bearing, and then I read reports of the new (at the time) ZX12's spinning #3 rod bearings (in Germany). And it seems to me like every story I have read about 750 fours spinning rod bearings, yep you guessed it, #3 again.

Two questions:

Do I in fact, recall correctly?
If so, then why always #3?

steell wrote:

If so, then why always #3?

There always has to be somebody at the end of the line...... that's probably the one who gets the wimpiest share of the pressure and feed.

i remember the early zx-10 and 11s back in early 90s having bottem end issues from lack of oil.mr turbo used to do something to restrict oil from top side of those motors back to the mains to solve the problem,i think you had to send the head and pan to them to have it done.the 11 i had was already done when i bought it,maybe check their site.