Clutch worm gear

[mofosheee]

Hello XS650 forum
I have a NOS but "uncut" sprocket cover for my XR 750 undergoing restoration. The attachment shows that female threads for the worm gear were never cut. The exact replacement part is unobtainable and fat chance finding somebody who would cut the threads. I've looked

Yamaha uses a similar system to actuate the XS650 clutch (attachment) as the XR750.
The Yamaha part I found on EBay is very close in size, but a little too small.

My intent is to mill the ears off theYamaha part, mill the HD sprocket cover to accept the Yamaha part and pin it in place.

Is there anybody out there in forum world who has knowledge of a slightly larger clutch worm gear assembly?

Thank you XS650 forum

 

[jetmechmarty]

 

[MacMcMacmac]

It might be easier to source a Suzuki unit that comes with the spiral gear inside a bearing cage with ball bearings in it. It seems easier to modify the case or the clutch mechanism with this design. It also has a steeper spiral, so you get more linear travel for the same amount of lever movement. They were used from the early 80's up until the last of the Katanas, and probably are still in use by some models.

 

[mofosheee]

Hi Mac

That's great info. A replaceable unit! I'm already liking it better than the HD and Yamaha design. Where did you find the picture please?
A hunting I go.............
https://www.partzilla.com/product/s...-2EYFvFPZ2J7siS_zgyrYOM3NRmO9JuwaAliiEALw_wcB

 

[DaveO]

I was just reading about this yesterday. The poster was fitting a Suzuki GT worm gear into a CB350 for a racing application. Hope this helps.

EDIT: This might help http://forums.13x.com/index.php?threads/honda-cb350-clutch-worm-drive-modification.314751/

 

[mofosheee]

That help quite a bit. Thanks!

 

[Jim]

There was a fella here that modified a Royal Enfield clutch actuator for his XS. Said it worked very well. I picked one up a while back but haven't done anything with it yet. What I like about it is that it uses ball bearings instead of a worm. That means much less friction. If it can be modified for the XS, it should also be doable for your application. I'll see if I can find his notes.

https://www.ebay.com/itm/224596945668?hash=item344b056b04:g:vX4AAOSwRLZUDYbH

 

[Jim]

Found it here. Not much hard info... but worth reading. Was done by @rusto

 

[mofosheee]

Just freakin beautiful....... sometimes we just have to innovate. Great help! Thanks