output shaft viable repair ???

[tommyardin]

Personal view

The sprocket nut is there to stop the sprocket sliding off the output shaft.

It doesn’t need to tighten flush with the sprocket to do this.

The output shaft is the fault on some of the fazers.  The grooves in some output shafts are cut slightly too wide.

This allows the sprocket to move backwards and forwards on the shaft when placed under load or off load.

Because the nut is tight against the sprocket it continually rotates slightly on the threads… wearing them out.

The answer in my opinion is grind down the flange on the sprocket nut so that when it tightens on the shaft it is simply flush with the sprocket but does not tighten against it…. And put some grease on the sprocket to further ease the junction between the nut and sprocket. 

Therefore there is insufficient ‘grip’ between the sprocket and the nut so it doesn't turn the nut.

In essence you want to tighten the nut up on the output shaft but not tighten it up against the sprocket.

Hi Paul, Just a quickie would that not allow the sprocket to chatter on the shaft causing to to the same shaft wear problems on the splines.

[Paul]

To Tommy


Yes......  but from memory some of the old Hondas used to have a slightly similar method of securing the sprocket and they didn't give problems


But more to the point if the output shaft has the over-size splines issue, the sprocket would chatter anyway even when the nut is tightened up on the sprocket......  which is why it wears the threads out.  But it doesn't seem to wear the output shaft splines out.   

[Fazerider]

Personal view

The sprocket nut is there to stop the sprocket sliding off the output shaft.

It doesn’t need to tighten flush with the sprocket to do this.

The output shaft is the fault on some of the fazers.  The grooves in some output shafts are cut slightly too wide.

This allows the sprocket to move backwards and forwards on the shaft when placed under load or off load.

This doesn’t tally with my experience. New sprockets have always been a tight fit to the shaft, quite difficult to get on in fact. I’ve often double checked the new sprocket actually has the right number of splines before trying again.

Because the nut is tight against the sprocket it continually rotates slightly on the threads… wearing them out.

The answer in my opinion is grind down the flange on the sprocket nut so that when it tightens on the shaft it is simply flush with the sprocket but does not tighten against it…. And put some grease on the sprocket to further ease the junction between the nut and sprocket. 

Therefore there is insufficient ‘grip’ between the sprocket and the nut so it doesn't turn the nut.

In essence you want to tighten the nut up on the output shaft but not tighten it up against the sprocket.

The trouble with that is that the nut will then have fewer turns mated with the shaft… albeit not to the extent of being as bad as the original 9mm nut.


Secondly, I’ve had nuts come loose where they are still unable to rotate because the tab washer is still working… the nut has been forced across the thread rather than coming undone. I suspect that giving the sprocket a longer run-up by not clamping against it might result in a slide-hammer effect and even earlier failure of the nut.


Thirdly, as Tommy points out,the spines will get worn if the sprocket is free to wander left and right rather than being clamped firmly.