GS 500 E crank threads ....

[fireyphoenix1...]

Hi all
Bit complicated so a quick explanation whats cause this issue
My GS500E locked up and it turned out to be the generator rotor ha disintegrated. I bought a very cheap broken bike to use as a donor.

Following the Haynes manual instructions i made a 36 mm spacer out of a bolt, put this inside the crank and wound my crank puller in ...rotor popped off with no issues at all.


Did the same with my bike .....
And the fecking bolt bent and jammed itself in the crank....
Three days a lot of swearing and enough use of needle nose pliers that i never want to see another pair in my life and i got it out ...



https://i381.photobucket.com/albums/oo256/fireyphoenix1989/1016970_10201403005815197_1487825593_n_zps5f60eaf2.jpg


Made another spaced from a cut up allan key as its hardened steel and fitted that in the crank shaft ...

https://i381.photobucket.com/albums/oo256/fireyphoenix1989/1005436_10201407853376383_510237931_n_zps540e0736.jpg



Popped the extractor on and after a day of tightening, heat and turning the air blue i have managed to get it off .https://i381.photobucket.com/albums/oo256/fireyphoenix1989/944564_10201407851696341_44309352_n_zps7dce2656.jpg

https://i381.photobucket.com/albums/oo256/fireyphoenix1989/1016862_10201408077381983_1077697710_n_zpsc2dacef0.jpg

Now we get to my new problem .....

The bolt knackered up the internal threads when it got twisted up :/.
This is the best pic i could take .. the first 5/10 mm of thread is knackered cant even get the bolt started ...


Ideas on how i can repair this... ???? https://i381.photobucket.com/albums/oo256/fireyphoenix1989/67789_10201408383229629_1931029886_n_zps087c6f2c.jpg
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2014 Aprillia dorsoduro 750 factory.

[Bezzer]

First thing would be to run the right size tap down it to try and recover it so the bolt fits.
You know the thread size?? be a fine thread no doubt and you'd probably have to use somewhere like Tracy Tools to get one if no one you know has one.
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I used to be indecisive but now I'm not quite so sure.

[fireyphoenix1...]

Well after searching net for hours i managed to find a local place that could supply a M12 X 1.25 Fine pitch thread cutter.
I also bought a can of cutting fluid as any little helps right ?
Anyway starting with a taper type tap i cut the first ten mm as i have read its easier to get the cut straight with a taper.
I got about 10 mm in then switched to a plug tap as it cut cleaner.

https://i381.photobucket.com/albums/oo256/fireyphoenix1989/540713_10201425551218818_219802176_n_zps40580be1.jpg

20 nerve wracking mins later the tap was able to spin freely all the way in and out.

Then i oiled the bolt and ran it in and out fully a few times to make sure the threads were good
https://i381.photobucket.com/albums/oo256/fireyphoenix1989/1001385_10201425550898810_256684048_n_zpsd7ac1890.jpg

I cleaned all the parts with some fuel and clean paper towels the used some 150 grit wet and dry to rough up the surface of the crank slightly.
Threadlocked the bolt and put some on the threads inside the crank.
Then installed the good parts off my donor bike and tightened the bolt to 92 ft /ibs

https://i381.photobucket.com/albums/oo256/fireyphoenix1989/1075837_10201425735703430_353005317_n_zps91d5e300.jpg

Just letting the thread lock set before i fit the new left side cover and stator, then oil and battery.
Should be up and running in a few hours .
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2014 Aprillia dorsoduro 750 factory.

[Pete.]

Sometimes the problem is with the spanner that's turning the nut.

In this case I believe it's more about the nut that's turning the spanner
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[fireyphoenix1...]

Im not sure what to make of that pete haha.
This bike only needs to give me a few months use as a commuter then im getting either a CBR 929 or 954 other main choice is a mid 90s ZX6R.
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2014 Aprillia dorsoduro 750 factory.

[Pete.]

I guess I wasn't being very charitable, should have at least said well done for persevering, and getting there in the end. Many people would have thrown in the towel long ago.

I'll try to redeem myself by offering some constructive comments.

The reason your bolt twisted up is because you used a very poor grade bolt as a packer. If you had used a socket cap (allen key head) it would likely not have bent up. Better still would have been to use something with the proper thread and bottom that out in the hole, then pop in a ball bearing to press against.

You should not have needed threadlock on that fine thread bolt. Minimum holding torque should be way lower than 92lbs/ft. Better hope you never have cause to remove it.

You say that you roughed up the crank - not the taper I hope? Self-holding tapers such as on that crank and flywheel are supposed to be ground to a fine finish, then fitted up perfectly clean and dry for maximum hold. Roughing it up will have reduced the holding capacity, though it might still be fine in use. At least the bolt isn't coming out.

I bet those fine thread taps weren't cheap. last one I bought that size was £27, though it's pretty good quality.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[fireyphoenix1...]

Manual i have specifies thread lock and between 86 and 96 Ft/ibs so i went in the middle.
The bolt extracted the first rotor off the donor bike without issues but the twisted when used on the good bike.
Given it had worked fine on the first motor i assumed the second would be fine .
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2014 Aprillia dorsoduro 750 factory.