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/2 flywheel bolt
Posted: Mon Aug 01, 2022 11:02 am
by mcsherry1328
Looking for the dimension of the flywheel bolt thread. The bolt diameter and the pitch. I want to buy a tap to clean threads on the crankshaft.
Re: /2 flywheel bolt
Posted: Tue Aug 02, 2022 10:50 am
by jwonder
The /2 models had Slotted M8 x 1.0 pitch screws. They were 20mm long and are available on Salis here:
https://bmwclassicmotorcycles.com/index ... 1210070155
There are 6.
So you would need an M8 x 1.0 pitch tap.
Re: /2 flywheel bolt
Posted: Tue Aug 02, 2022 12:17 pm
by mcsherry1328
Sorry, I didn't specify that I'm looking for the dimensions of the large flywheel bolt that secures the flywheel. The bolt is 18mm just looking for the pitch. Is this specific to BMW or should I be able to find a tap to fit crankshaft ?
Re: /2 flywheel bolt
Posted: Tue Aug 02, 2022 1:09 pm
by jwonder
Salis has them listed as M18 x 1.5.
I am not sure why you are doing this, but two things I would note:
1) if you do use a tap then I would use a bottoming tap. I would wonder if the threads on the bolt were pulled before the internal thread in the crank.
2) I would use a thread chaser versus a a tap as I would think you would not want to remove any material from the threads.
I would be interested in the reason for the tap for future note.
Hope this helps.