I installed a Vista Cruise universal throttle lock on my KLR.
I filled the gap of the tab with JB Weld so that I could drill a mounting hole in it.
Here's a pic of the throttle lock with the tab extended with JB Weld-
Then I installed the lock over the throttle handle, lined it up with the lower cable cover, and started to drill into the lock. Then I removed the lock and finished drilling the hole. Then a quick touch up with the satin black paint-
Now I had to reinstall the lock so that I could drill the hole into the lower cable cover. I positioned the lock and started to drill through the lock's hole into the lower cable cover. After the lower cable cover was marked with the drill bit, I again removed the lock and the lower cable cover.
I then finished the hole in the lower cable cover (in a vise), tapped the hole for a 8/32 SS Button head allen screw, blew out the shavings, and reinstalled it.
Here it is installed, with new hole goodness (sorry it's fuzzy)-
I then reinstalled the lock and set to finding the correct length for the 3/8 long 8/32 screw that I bought. It was definitely a bit too long 'cause it was hitting the throttle cable bail. I also found that when installed with the screw, the lock was racking to the ouside of the bar. I used 2 peices of 3M double sided foam (Home Depot) to fill the gap between the lock's tab and the lower part of the cable case. After using the foam tape, the 3/8 long screw wasn't binding the bail, so I didn't have to shorten it.
I later found that I had drilled the mounting hole too high, so I filled that hole with JB Weld and drilled and tapped a new hole to mount the Vista Cruise. This put the thumb lever lower and allowed easier engagement/disengagement.