Flywheel nut thread

[tschisi]

Hi!

I can?t attach my new flywheel nut to the crankshaft.
It goes 1 or 2 turns and that?s it.
It seems that the threads don?t fit and the crank would cut a new one into the nut.
I know that my frame is from March 1990 (my nut is also for a 1990), but maybe my engine isn?t?!
Engine number is KX500BE011113.
I measured the crank thread as something like 12x1,22mm.
Do you know if there were changes in the crankshafts?

thx

[jonny500]

it sounds like you are trying to put a 12mm course thread on. the nut should be 12mm x 1.25mm where as a course thread is 12mm x 1.75mm. i would get a new nut from kawasaki to be sure. as damage to the crank thread will be expensive. i see you are in austria. if you cannot get one let me know and i will give you some contacts from the uk or send you one i have here for nothing
best regards
john

[tschisi]

I got mine from kawasaki.
 

[jonny500]

if that is new nut then the thread on the shaft must be damaged or stretched. you need to get a 12mm x 1.25mm die and try and revive the thread but be carfull as i said before if the thread on the crank shaft is damaged it is expensive. if the thread is damaged beyond repair you could cut it off and drill and tap a female thread in to the center of the crank and use use a bolt. i am not recomending this as it is a bit drastic but could be an option as a last resort.
regards
john

[cbxracer30]

You may want to try a thread file , they are a great too; to have . You can usually fix up anything threaded with one of these. And test fit the nut on another bolt the same size and thread just to make sure it is not the nut that is screwed up , We have all got brand new parts that were wrong or screwed up from the factory- so much for quality checked. CBX

[BDI]

How was the flywheel removed from the crank? I have seen the threaded portion of the crank get mushroomed from pulling the flywheel more then once. Usually this happens from the old school method of tightening the puller and giving it a sharp rap with a hammer to pop the flywheel off. what kind of puller did you use to get the flywheel off? was it a claw type or the one that threads in. When this happens the crank will look fine to the eyeball but the nut will not screw on more then a little bit. If this is the case you will have to recut the crank end with a die to get it back to the right size. You have to use cutting oil and go slow, keep backing the die off and cleaning it. You will be doing more then just cutting threads, you will also be resizing the crank.

[tschisi]

I used a puller that threads in.
The thread on the crank is ok, i checked it with a thread cutter.
But the nut i have from kawasaki is not a 12x1,25!!!
Also checked with a thread cutter.
I think i will get one from another shop...