What size die/tap for crank thread 350 sport?

[Matt Hale]

Hi all
The thread on the end of my crank on generator rotor side [1979 350 Sport] is a little worn and a new nut has immediately gone stiff when put on end of crank.
Does anyone know the size of the thread on the crank end? I am thinking I could use a die to improve the thread so need to know what size die...Also...is it fine thread?
The nut is 22mm socket...
Any other method suggestions welcome...
Thanks
Matt

[Fastmongrel]

I don't know what size the thread is but I would beware using a thread cutting die to try and repair the threads. The die will cut metal away however careful you are if you remove too much you won't be able to tighten the nut. To repair a damaged thread it's best to use a thread chaser this doesn't cut the metal but reforms bent or bashed threads.

You can get sets of male and female thread chasers for not a massive amount.
https://www.amazon.co.uk/Mrcartool-15-P ... CYQAvD_BwE

[norbert]

You can try a thread file if it is not damished en all the thread. Don´t remember the tread an in the moment I´m in Cadiz so cannot look. But I´ve cured the thread of a 500 with this file

k-DSCI1091.JPG (101.3 KiB) Viewed 2780 times

k-DSCI1087.JPG (26.81 KiB) Viewed 2743 times

[Matt Hale]

I don't know what size the thread is but I would beware using a thread cutting die to try and repair the threads. The die will cut metal away however careful you are if you remove too much you won't be able to tighten the nut. To repair a damaged thread it's best to use a thread chaser this doesn't cut the metal but reforms bent or bashed threads.

You can get sets of male and female thread chasers for not a massive amount.
https://www.amazon.co.uk/Mrcartool-15-P ... CYQAvD_BwE

Apologies for the delay t o thank you for this info. Been away from bike but back now and will see if I can use a thread chaser.

[Matt Hale]

You can try a thread file if it is not damished en all the thread. Don´t remember the tread an in the moment I´m in Cadiz so cannot look. But I´ve cured the thread of a 500 with this file

k-DSCI1091.JPG

k-DSCI1087.JPG

Thanks Norbert- if you know the thread size it would be useful. Apologies for my delay in replying.