Kawasaki Motorcycle Forums banner

1984 ZN1100 Crankshaft end float

8K views 84 replies 9 participants last post by  WFO-KZ 
#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.

Wheel Automotive tire Light Locking hubs Motor vehicle
 
See less See more
1
#32 ·
Technically we are not supposed to direct members to a competing web site. But anyone is free to use google which is what I did and came across the same link as haybaler posted. It is somewhat helpful, but I am pretty certain my crank has not twisted which is mainly what that thread is about.

A this point I am torn between three options:

1) Run her until it explodes. (maybe this will never happen)
2) Part it out.
3) Split the cases to find and maybe repair the cause.
 
#35 ·
Same thing with the early GS1100 Suzuki's. I think the 1150's are one piece forged. I never liked the idea of pressed cranks. It seems to me if they are going to do that, then weld them up, make them flat plane and reap all the benefits. Ah, what do I know. I wake up and go to sleep everyday with the realization that I haven't a clue as to what's going on. I'll probably utter my last breath and waft out a hissing, "What was that all about?". 🤔
 
#37 ·
$89 buck is more than reasonable. I won't even take my Tig welder out for that much. Redoing the whole crank for $1K , that is a "gulp" for sure. Doesn't it seem that the only thing that would allow that crank to move like that would be an outer bearing, or one end of the pressed crankshaft having lost it's location? Also, wouldn't it have to be the one on the opposite side? If the number 5 bearing lost the pin, then the movement would be either the end bearing(s) have moved. The crankshaft spreading might cause that end to come out, but the movement in and out is really weird. The connecting rods would not allow that kind of movement, the only thing left is a problem with the outer pressing of the crankshaft ends, and without seeing one in the crankcase, I don't know how you could check these parts without a tear down. The rods would bend with that kind of play, methinks. I think the crankshaft is being held in place, but one of the crankshaft ends has done something that defies physics. :)
 
#40 ·
I am surprised that so far, nobody has claimed to have split the cases of any Kawasaki 4 cylinder engine that uses roller bearings. This would include the Z1, KZ900, KZ1000, KZ1100, ZN1100 and the police versions. Perhaps that is a testament to their reliability?

To answer Kawasakian's question regarding how crank end float is controlled and to comment on his theory, I did some digging and found this photo of a KZ900 crank for sale on fleabay.

Note that in the photo, the outer bearing races are totally free to slide back and forth by a very large amount. These bearing races will be somewhat retained from axial movement once they mate with their corresponding set pins that are in the crankcase bearing bores. However, I believe the main function of the set pins is to make sure that the oil hole in the outer race, stays lined up with the oil feed hole that is in the crankcase. Since that hole is generously oversize, the set pins do not have to be a tight fit.

However we do know that bearing #5 is designed to fix the crank to the crankcase to prevent axial movement. So all thermal expansion will move outwards from bearing #5. This outward movement is easily permitted by the free floating design of the outer races of the rest of the bearings. Thermal expansion would be in the order of only a few thousandths of an inch, so where did 1/8" of float come from?

My current theory is that the tiny pin that locks #5 bearing to the case has sheared or was omitted by whoever may have split the cases in the past. Without that pin, the crank is free to move quite easily based on what I see in the drawing below. Bearing #5 is the one right next to the large gear on the RH end of the crank. Comments?

Auto part Machine Nickel Bicycle part Titanium
 
#41 ·
I think you're on the right track. Judging from this pic in the build link referenced earlier it appears the outer counterweight limits float to that side.

Have you drained the oil lately and examined the filter for metal shavings? An oil analysis can be done for a reasonable fee through Blackstone Labs. If the engine isn't eating itself I would just ride it. Locally. ;)

Engineering Auto part Machine tool Machine Cameras & optics
 
#43 · (Edited)
That crankshaft is using all the available play possible, looking at the last picture, it would seem. Something is not right. Some bearings have keepers split in half to locate, but there is no indicator of anything even taking such a stop. The journal on #1 piston doesn't even seem to be able to allow such movement. I have no idea of what is going on. It would be very interesting to see ultimately what is going on. Isn't Bearing #5 just a plain bearing meaning the engine case journal would hold it in position? Bearing so shiny, lubed with oil, it wouldn't offer much friction. :)
 
#44 ·
Kawasakian, not sure which photo you refer to in your post #43, but I am 100% certain that all six bearings are rolling element bearings, five of which are roller bearings and then we have bearing #5 (the mystery bearing) which should be a different kind of bearing... one that can take some thrust loads. So, no plain bearings in this engine.

Not sure where you think you are seeing split keepers. On the last photo I added, the center bearings may look like one that is split, but they are actually, two separate bearings, but their outer races have slid towards each other and are almost hiding the camshaft chain gear.
 
#45 ·
I've not seen split keepers in bike engines, only automotive. The mystery bearing is the answer to the issue, methinks, but all the other journals are so tight. This is above my pay grade. It will be interesting to see if someone comments, or you end up taking the lower end apart. Those engines are good for many other kinds of vehicles, such as trikes. I would like to see what's going on as I want to make a tadpole type trike using a Kawasaki 1100 engine with shaft drive, so I can hook it up to a solid axle with a differential. ;)

This style, with a Kawasaki engine though, and a front brake, different looking tank, and a little wooden pick up box in back for carrying groceries. This is Ian Roussel's trike. He used a VW carb and made a custom intake out of exhaust pipe, on a Goldwing 1100 engine!! :


 
#46 ·
The journals do look tight, but until you see one up close there is no way to know for sure. All it needs is 1/16" of clearance on either side of the bearing and then it could move by the 1/8" that I think I am seeing.

Speaking of that, I am pondering how best to attempt an accurate measurement of crank end float WHILE the engine is running. The ignition rotor will be spinning at about 1000-1200 RPM and I don't want to burn up the tip of my dial indicator with steel on steel rubbing. Any ideas?

Cool trike, but I cannot say I am a fan of the coffin tank. But otherwise a nice adaptation of a Gold Wing.
 
#49 ·
If you put a drop of 30 weight oil on the tip of the dial indicator, and end of the crank, it would give you enough time to get a measurement. I used to have to do high speed out of round tests on a specialized machine for bending up to 10" diameter screws used for all kinds of things, this particular one was for raising and lowering a mount for a missile on a Destroyer. It spun really fast and they wanted to see a dynamic out of round measurement. The same machine would be used to straighten it out. It was more of an art than anything that can be taught. Once I figured it out, I regretted it, because every time an order came in, they would give me the job, and some days, you just don't have the touch. ;)
 
#51 ·
That's a good idea. I have all Brown and Sharp, and Mitutoyo indicators, and a few Starret. I am very careful with them. The Starret comes with an extension arm it on a pivot, to the end actually never touches the actual dial indicator. It is very old, in new condition, and has many little set ups for doing oddball kind of measurements. They sell the same kit for $309 dollars, mine is over 45 years old! I know it's American made. It's range is .200" of an inch. :)

The pic below is the one I collections have:

 
#52 ·
Those are very nice (and expensive) dial indicators. My Fowler was not cheap either, but it is like a poor-man's version of a Starrett or Mitutoyo. When I was active in the trade I only bought Mitutoyo or Starrett. I also inherited some Brown and Sharp. All were excellent quality.

At our shop we had the exact same kit as in your photo. The transfer arm would be perfect for this situation.

Here is mine, but I think I got it on sale for around $140.
 
#53 ·
I purchased virtually every Dial Indicator I found at Tag sales, it's amazing what people think are junk. I have a Brown and Sharp 5" inch sine bar in the box, I paid $10 bucks for it. I have a huge collection. They are each in their own plastic bags, and I have 3 that read in .0001" tenths of a thousands of an inch. You can see the heat affect the machined part. Brown and Sharp, another mainstay, and I have some of them too. I also have a good collection of the test indicators, which are excellent for locating hole centers of milling machines. That transfer arm has so many uses, and it's extremely hard. Mine shows no signs of wear. The Horizontal Indicators are fantastic, but they have to be at 30 degrees to actually measure something, otherwise, they are good for indicating flatness, hole centers, etc. The tip is fully adjustable, as I'm sure you know. :)




 
#55 ·
I found a site that lists the bearing that I believe is the "mystery bearing #5". I think the site has mislabeled this bearing however since they say it is a center bearing, which we now know for certain are roller bearings, yet this one is a ball bearing.

Notice the tiny pin that locks the outer race to the crankcase as a positive way to control crankshaft end float.
Did someone rebuild my crank and substitute an ordinary ball bearing with no pin? Could the pin have sheared if the crank took a hard hit in an accident? Here is a clip of the bearing:

Wheel Automotive tire Rim Bicycle part Auto part


And here is a link to the site that sells those bearings;

#5 bearing with pin
 
#56 ·
Very possibly. Ultimately, you have to decide if you are willing to live with it, or wish to take apart. It's hard for me to say, "rip apart the bottom end and ust find out", as my Spinal Cord injuries preclude me from doing anything that is not imminent. I don't know if this is imminent. You have other bikes you can ride, and have the expertise to do the job. You also have the desire to get this issue over. That seems to me that you're probably going to tamke the bottom end apart. A thread I will read with much interest. :)
 
Top