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Wish I had more direct info but age and time elapsed has dimmed my memory. I have split cases on both old Kawasaki and Suzuki fours but it was just to long ago to have specific memory of end float.
I do not believe those pins are to prevent end float. I have encountered both locating pins and split rings on an endless array of motorcycle and snowmobile engines.
Reason one... I have never seen a rolling element bearing that was not securely captured when the case was torqued.
Reason two... if the outer race is pinned it provides no protection from thrust loads to the bearing.
I believe the pins and split rings are there to accurately position the shaft and insure the bearing is square to the case before torqueing.
If the bearing outer race was so loose that it allowed lateral float it would likely hammer the case over time and cause all manner of problems.
I suspect that there would be very little lateral movement under dynamic loads. Rods and cam chain would tend to self center, this would be particularly true in an engine with straight cut gears.
You might consider pulling the alternator cover to see if the lateral movement has caused any interference or wear. As good as those old engines were the casting and machining left a lot to be desired.
 

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To clarify... straight cut was referring to primary drive gears.
Hammering the cases was referring to the fact that if there is any clearance at all the cyclic loads of combustion acting thru the bearings would slowly damage the cases.
 

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Discussion Starter · #63 ·
Well,,, IF the bearing race is floating, Is it wearing the case to where you'll need it line bored and all new main bearings?
That would depend on if the bearing is spinning in its bore or sliding in its bore. Either one will cause wear but the latter I would think would wear quite slowly. It is definitely not worth line boring. I expect the bearings would be fine. Hardened steel vs aluminum...steel always wins.
 

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Discussion Starter · #64 ·
Wish I had more direct info but age and time elapsed has dimmed my memory. I have split cases on both old Kawasaki and Suzuki fours but it was just to long ago to have specific memory of end float.
I do not believe those pins are to prevent end float. I have encountered both locating pins and split rings on an endless array of motorcycle and snowmobile engines.
Reason one... I have never seen a rolling element bearing that was not securely captured when the case was torqued.
Reason two... if the outer race is pinned it provides no protection from thrust loads to the bearing.
I believe the pins and split rings are there to accurately position the shaft and insure the bearing is square to the case before torqueing.
If the bearing outer race was so loose that it allowed lateral float it would likely hammer the case over time and cause all manner of problems.
I suspect that there would be very little lateral movement under dynamic loads. Rods and cam chain would tend to self center, this would be particularly true in an engine with straight cut gears.
You might consider pulling the alternator cover to see if the lateral movement has caused any interference or wear. As good as those old engines were the casting and machining left a lot to be desired.
Yes, all 6 bearings will be captured when torqued, but capturing the outer race of a roller bearing does nothing to restrain it from side loads which is why my service manual states that only bearing #5 takes the axial load. Allowing the other bearings to float means thermal growth of the crankshaft is easily accommodated. Look back at one of the photos I attached and you will see that the outer race of the roller bearings can be slid right off the bearing so capturing it, does not prevent the rest of that bearing from moving axially.

That said, you could be right that the tiny pin is not there to prevent axial movement. That part was just my theory and without taking it apart and studying it we just don't know. But we do know that a ball bearing can take axial loads so it makes sense that bearing #5 is a ball bearing and my most recent picture confirms that. So if #5 is properly clamped it should not allow the crank to move axially, but it does. Maybe #5 has failed, but no abnormal engine noise so far and why would just one bearing fail? Seems strange.

I agree that lateral loading should be low and should be self-centering, but as someone pointed out, with the bike idling and on its side stand, there would be a tendency for the crank to try to slide over to the low side. Again this would be a small load, but one that needed to be addressed and the engineers did so with bearing #5.

It's an interesting discussion and I thank everyone so far for their input. Hopefully this might help someone in the future. We started without much info and gradually we are filling in the information gaps.

PS- I did pull the alternator cover, see post #13.
 

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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. ;)
I have split cases on several Z1's & KZ's & J models. I don't remember any special attention to this issue. I don't remember any thrust washer or any other locating devices to prevent the longitudal movement of the crankshaft. Was the crankshaft trued? If I remember correctly 0.002 is the side to side clearance on the rods to the crank throws.
 

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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.
All through the "J" model series were roller bearing cranks. Seems to me you have an untrue crankshaft. Meaning one, or more, of the throws has moved on the pressed pin. This was not uncommon in the early days. It ususually showed in longitudal movement on one or more of the piston heights & not on the longitudinal axis.. I twisted (2) over the years while drag racing. Had the crank trued, pins welded in place, & balanced. Never had any other issues once this was done.
 

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All through the "J" model series were roller bearing cranks. Seems to me you have an untrue crankshaft. Meaning one, or more, of the throws has moved on the pressed pin. This was not uncommon in the early days. It ususually showed in longitudal movement on one or more of the piston heights & not on the longitudinal axis.. I twisted (2) over the years while drag racing. Had the crank trued, pins welded in place, & balanced. Never had any other issues once this was done.
Sorry I meant vertical movement on the pistons,
 

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I have split cases on several Z1's & KZ's & J models. I don't remember any special attention to this issue. I don't remember any thrust washer or any other locating devices to prevent the longitudal movement of the crankshaft. Was the crankshaft trued? If I remember correctly 0.002 is the side to side clearance on the rods to the crank throws.
That 0.002 is mm not inches. After reading on & looking at your photos, you definitely have a concerning issue.
 

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Discussion Starter · #72 ·
Thanks for the response. What we have determined so far, is that unless you press the crank apart, you won't learn the magic of bearing #5 as that is the one that takes the sideways thrust of the crankshaft.

Since the engine runs and sounds perfect, I am for the time assuming that the crank pins are still where they should be, but bearing #5 has lost its grip on the cases and is sliding sideways along with the crank.

It is my belief that bearing #5 is not a roller bearing like its brothers since it has to take thrust loads. Ordinary roller bearings are not designed for thrust, so I think #5 is a ball bearing. Would love to know, but more out of curiosity since I am unlikely to fix this crank... or the bike for that matter.

But thanks again for you input.

PS- when you make a typo, you can edit your post. It will ask for a reason, and you can just say "fixed typo" or something simple.
 
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