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Discussion Starter · #1 ·
As noted in the title, I have a 1984 ZN1100 with about 42,000 Kms on it.

While tuning the carbs and with the RH side ignition cover removed, I was horrified when I noticed the ignition rotor was drifting in and out by about 1/8" (3mm). I checked the rotor bolt and it was tight. I removed the rotor and all looked fine.
With the engine turned off, I cannot duplicate the drift by pulling or pushing on the rotor. Clearly there is too much resistance unless the engine is running.

Since the rotor bolts directly onto the end of the crank, it must be the crankshaft that is drifting... YIKES!!!

So, because I have never torn down any Kawi 4 cylinder engine down to the crankshaft, I need input from anyone with this experience. What controls end float of the crankshaft and why is mine drifting so much?

I should add that the bike runs fine and sounds good, but this much end float CANNOT be normal. I am stumped.

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Discussion Starter · #3 ·
True it does not seem to bother the ignition, but what about the conrods going sideways? What about the hy-vo cam chain going sideways and what about the crankshaft ball or roller bearing races that have to be moving sideways on their precision fits?

I think each of the main crank bearings is retained with a dowel pin, so what the heck happened? Did someone leave out the dowel pins?

I really need someone who has torn these engines down before. It does not have to be a ZN engine. The ZN is much like all of its KZ brothers when it comes to the crank.
 

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You're absolutely sure there isn't a piece connected to the crankshaft that the piece bolts into? It seems like an awful amount of play. You'd think a big "crunch" is around the corner. I think that piece is connected to the crankshaft but is not part of it. I don't have the manual on it, but after looking at pics on the net, it seems like that is the only way you could get that kind of movement. The connecting rod journals would not allow for that much movement. If you could look at the other end of the crankshaft and see the same movement, then something is horrifically wrong. I'd open the other cover and put a dial indicator and see what kind of movement your getting. There is a pin numbered "555" in the parts diagram, but it doesn't show where it goes on that side. A dial indicator should give you a couple of thousandsths movement, but the other end (pick up end), while being turned by the crankshaft probably cannot slide along that longitudinal axis. Just speculation on my part. Best of luck. ;)
 

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Yeah, that's a little spooky. Usually, I find some thrust surfaces in the crankcase that locate the crankshaft, and do not allow any sideways play. But it appears that some of the older motors didn't really need that much control since nothing is pushing or pulling on the crank shaft. The cam chain is in the middle and the primary drive is straight cut so no sideways force to speak of. Still, you gotta wonder whether there's some flexing of the con rods. Next time I'm at the race car shop, I'll ask some more experienced engine builders. Meanwhile, since it runs and sounds okay, enjoy! Cheers!
 

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I wouldn't worry about it. If it is running the way it always has been, then just keep riding. There'll be enough time to fret over it in some unforeseen trouble..........................Staying in the motorcycle land of faeries, lest your feet touch the ground and ye become mortal.
Come away, O human child!
To the waters and the wild
With a faery, hand in hand,
For the world's more full of weeping than you can understand.....................Yates



Been reading too much "Yates" lately. :)
 

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Discussion Starter · #7 ·
You're absolutely sure there isn't a piece connected to the crankshaft that the piece bolts into? It seems like an awful amount of play. You'd think a big "crunch" is around the corner. I think that piece is connected to the crankshaft but is not part of it. I don't have the manual on it, but after looking at pics on the net, it seems like that is the only way you could get that kind of movement. The connecting rod journals would not allow for that much movement. If you could look at the other end of the crankshaft and see the same movement, then something is horrifically wrong. I'd open the other cover and put a dial indicator and see what kind of movement your getting. There is a pin numbered "555" in the parts diagram, but it doesn't show where it goes on that side. A dial indicator should give you a couple of thousandsths movement, but the other end (pick up end), while being turned by the crankshaft probably cannot slide along that longitudinal axis. Just speculation on my part. Best of luck. ;)
Yes, I am sure there is no intermediate piece of the crankshaft that is causing the end float.

Yesterday morning I did exactly what you suggested. I removed the alternator cover, put a dial indicator on it, and fabricated a light duty puller out of wood so I could try to move the ignition side. As the ignition side moved, so did the alternator. I guess this proves the crank is not broken so that is good news.

The pin 555 goes into the end of the crank to keep the ignition rotor in the correct orientation.

I must say I have never come across anything quite like this. The bike was sold to me as a "non-runner" with the former owner stating that the only issue was some burned electrical wires. Hmmmm. I wonder.
 

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It may just be the design. Those pistons and Connecting rods will hold the crank in place, and any movement will be within spec of the elastomeric qualities of the parts, if it was designed that way.. You ride the bike. If it feels good, then keep going. Could you imagine taking it apart and finding out there's nothing wrong?!? :)
 

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Discussion Starter · #9 ·
Yeah, that's a little spooky. Usually, I find some thrust surfaces in the crankcase that locate the crankshaft, and do not allow any sideways play. But it appears that some of the older motors didn't really need that much control since nothing is pushing or pulling on the crank shaft. The cam chain is in the middle and the primary drive is straight cut so no sideways force to speak of. Still, you gotta wonder whether there's some flexing of the con rods. Next time I'm at the race car shop, I'll ask some more experienced engine builders. Meanwhile, since it runs and sounds okay, enjoy! Cheers!
Good points. I have been digging into it, and the manual says:

" The #5 bearing outer race works not only as a bearing outer race, but also as a stopper of crankshaft axial movement (thrust bearing).


Unfortunately the manual does not explain, how this is accomplished. Sure, they can use a deep groove ball bearing that can withstand moderate side loads, but how do they fix the bearing so it cannot move sideways?
 

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I just found this. The inside bearing acts as a thrust washer. The tolerances given are pretty tight. This was for a KZ1100, I found it on "manualslib". It's kind of scary. If what it reads is true, it depends on how much movement you read determines where you're at. The solution for any bad bearing is replace the crank.. If the crank let go, or any of the connecting rods, the forces would probably trash the engine cases. Look in your manual and see if it matches the attached picture. If it's a pressed crank, which a lot of these were, it may have slid out, which means it could be welded after pressed back into place. Not a cheap endeavor. :)

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Discussion Starter · #13 ·
I intentionally only moved it by 0.025". Remember, I had to use a puller to make it move without the engine running. This confirmed to me that the crank was not broken.

By eyeball, with the engine running, it looks like the total movement was about 1/8", in other words it drifted in by 1/16" and then drifted out by 1/16".

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Seeing as how they are pinned and the edges acting as thrust bearings per the above, I'd agree the main bearings might be shot, something is or you wouldn't have the play. if it's the main's dowel pin hole worn, the case will be worn down where the main is sliding back and forth. Though I'd think the play should be detectable by hand. The motorcycle does not have the force a car engine has on the thrust bearing, If it's a gear drive primary and helical-cut gears you'd get some side force... On a car, If it's a stick you put the pressure plate springs against it every time you push the clutch in.

On another note, I once had a guy bring me an old VW to look at, said the shop told him the crank was broken. He drove it to my house... Sure enough, When I grabbed the rear pulley, it wobbled,,, pulled the engine, The crank had split dead center between #2 and 3 main bearings. shortest path across casting. the halves were pushing each other around in the case. Which totally destroyed the case inside. I still can't believe he drove like that for probably 30 miles at a minimum. Tough engines..
 

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Discussion Starter · #15 ·
Thanks for all the input so far from all of you.

Does anyone know if Kawi uses roller or ball bearings for their big-bore 4 cylinder engines?

I can't see the bearings being shot since 1/8" of axial movement should also allow 1/8" of radial movement which might cause pistons to collide with valves or at a minimum, I would think it would make horrific noises which it does not. It sounds and runs just fine.

However, if somebody had it apart and did not install whatever pin is needed to prevent end float, well that would explain everything. The reason I cannot move it by hand is because I have to overcome the force of the press fit on the bearings.
 

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Discussion Starter · #17 ·
I think you misunderstood me. The total movement of the crank is way more than 0.025". It is closer to 0.125"

But thanks, I think you are correct about roller bearings, at least that is the way I remember it. They do look to wide to be ball bearings unless they are double-row ball bearings.
 

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Yes, it is. The Kawasaki Clean air system makes me think a lot of superb bikes we lost because of poor dealerships service centers. In the dealerships I worked in, we made so little on new motorcycles. The money was in accessories, and in service, good service, and good accessories, and good access, fast access to O.E.M. parts for the DIY mechanic. Supporting that mechanic too. On these motorcycle forums I belong to I read about so much stuff the dealerships just missed, like the crappy Suzuki electronic Stator/Voltage R/R design. So many bikes with blown electronics, with the stock put back in and the bikes breaking again the same way back then. For a while you could get a GS1150 for a song, now that people know how to fix them, they aren't cheap to buy anymore. This is good for people who join these forums. They can buy bikes, fix them, and have a excellent bike for not much cash, a fraction of what a new one costs. The guys who amaze me are the ones interchanging front ends from different manufacturers, and coming up with really hot bikes. That is something I wish I knew more of.

If I can, I would like to purchase maybe 1 or 2 more bikes to teach my son how to turn over. They will have to be special ones. :)
 
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