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front sprocket nut question

1.1K views 9 replies 5 participants last post by  spinko  
#1 ·
Hi,

I have what might be a stupid question, but anyways....

I am just changing the front sprocket on my '95 yamaha seca 2. As I was putting the nut back on to secure the sprocket, I realized that it threads on and then becomes loose as it gets right up next to the sprocket??

the actual nut only has a couple rounds of thread on it, and the rest looks like it's machined away (it looked stripped at first, until I realized that the 'stripped' portion wasn't in a spiral, but rather just machine marks)...

Is this normal?
I'm not sure if I should be looking for a new nut, or just putting it back on. My gut instinct is not to trust it, at least until I hear otherwise... Thanks in advance for your responses!
 
#4 ·
fastfitter said:
Is the sprocket seated properly on the shaft? Maybe the blank bit of the sprocket nut sits over the gear shaft?
That's what I'm thinking but they usually use a thick washer as a spacer for that sort of stuff.

If it's just uneven tension in the threads then it's likely that it's just the outer threads have some rust or grit in the thread valleys.
 
#6 ·
no, the threads that are on the nut are good, but there's only a couple rounds on the thread. Then the rest of it is machined down or something... it's really weird.
When I screw the nut on, it goes on fine until right when it gets to the sprocket, then it kinda goes loose and I can turn it around freely. I'll take the nut into the shop tomorrow morning and see what the mechanics say there... It just doesn't look right to me. The sprocket is keyed, so my one guess it the nut kinda just acts to hold the sprocket in place, but I'm not sure why it needs to turn around freely like that.
I should note, there is a washer there with the tabs that "lock" the nut so it doesn't rotate, but when the tab is down the nut can turn....
I'll let you know how it turns out tomorrow.
Cheers.