New throttle assembly, different throttle cable needed

Hi All

I am about 2 years into my kz500 cafe racer style project, and can't count the number of times I have searched this forum to help me along the way.  So a big thanks to everyone! 

Getting close to competing things, but I have run into another issue.  I have replaced my throttle assembly (on handle bar) with an aftermarket unit, and when purchasing it over a year ago, I didn't really read much into the thread sizing for the 2 cables. Low and behold when trying to install cables today, the push cable thread required for this throttle is M12 x 1.0, and the cables I have (both pull and push) are M10 x 1.25. 

The way I see it I have 3 options:
1) find some form of an adapter (helicoil?) to change the thread of the cable connector from M10 x 1.25 to M12 x 1.0
2) find a cable with similar specs (length, and carb side design) that has the M12 x 1.0 thread
3) find a throttle that uses M10 x 1.25 for both push and pull 

Note, the bike is an 81 kz550 C2 LTD, but I have swapped the handlebars over to a drag style.

Any advice? 

I'm not suggesting this is the way to go, and I'm not suggesting you should do this. I'm just making a remark.

Whenever I get a bike, I ditch the push cable altogether. Literally, I just bin it. As long as the throttle return spring is in good condition, clean and working properly, the throttle always snaps shut on its own.

I find that riding with just a pull cable is more enjoyable, as I like to blip on downshifts. However, some people nowadays consider that ditching the push cable is a dangerous practice.
Obviously, seek the advice of a qualified mechanic and not a random on the internet. But me, personally, if I were in your shoes, I would just bin the push cable without a second thought.

Whenever I get a bike, I ditch the push cable altogether. Literally, I just bin it. As long as the throttle return spring is in good condition, clean and working properly, the throttle always snaps shut on its own.

 I NEVER recommend removing the push cable, it wasn't fitted for nothing,  regardless of how good a spring you think you have, springs snap from fatigue, something you will never see until it happens, spring mounts break,  why do you think EVERY motorcycle manufacturer using these style of carb use one ?  You'd only need for the throttle not to return for a split second for it to possibly end up catastrophic, why even take the risk ?   If you want one cable, use CV's  . 

My KZ550 variant had CV carbs (Teikei 26, I think). No problem using just one cable on those.

Th OP has VM style carbs, they need a return cable..