crapped up threads need to know size

i messed up the threads on my main drive, where the front sprocket goes on, i need to know the next size down so i can re-thread it,
o yeah '77 kz750 b2 twin

How the hell did You do THAT?:ohmy:

Or maybe You don't want to talk about it?:lol:

down shifting from top gear, nut came off, sprocket came almost off, and smoothed out the threads,
yikes

The threads on a Z1/KZ900/KZ1000 are 20mm and I THINK (not positive) 1.5 pitch. Use a pitch gauge to get the pitch for sure.

See if the next under size in SAE might not be a better choice....(less material removed)

thanks y'all, i imagine i'm not the only one whom this has happened to, i want to go buy the stuff to do it this for weekend after next so i can get on the road again.

Post edited by: cratgo, at: 2007/05/01 22:39

what can i say , for about 2 minutes, i was like what the freak is going on!:sick: :pinch:

Post edited by: cratgo, at: 2007/05/01 22:42

From the pic.
That looks like I would try to fix it first.
Get a thread file and lightly dress it up .
Then a NEW nut .
And a NEW tab washer , maybe 2 and snip the tabs off of one of them .

Assemble dry to make sure everything fit's tight and right .

Then take it apart and reassenble with just "2" drops of red loctite .

All the nut does is hold the sprocket on the splines.

cratgo wrote:

That doesn't look that bad. Not bad enough to require undercutting. Can you try a metric die?

Sometimes you can save a thread by cutting a groove in the nut perpendicular to the threading with a triangular file. It acts like a thread cutter, and gives the material somewhere to migrate to while being rethreaded. Poor man's die.