For carbed bikes, but will work with EFI as well.
Proper method to throttle adjustment:
1.) Loosen and put slack in both the throttle (pull) and Idle (return) cables.
2.) Turn your handlebars straight while adjusting the throttle cable, and to the left, while adjusting the idle cable.
3.) Adjust your throttle (pull) cable until the carb linkage arm bottoms out on the throttle stop, then back it off about 1/16". (a hair's width) At full throttle, you want a crack of daylight, but not contacting the throttle stop.
Failure to adjust the throttle cable first can result in a bike who's throttle is not capable of providing WOT response.
4.) Then, adjust the Idle (return) cable until there's about a 1/4" slack in the throttle grip, by adjusting the idle cable. (back and forth movement of the throttle tube)
5.) Start bike and move handlebars back and forth, making sure idle remains the same, and the natural movement of the throttle cables isn't pulling on anything, causing the RPMs to rise. Move bars to both left and right.
If a cable is improperly adjusted (too tight) by turning the bars can be enough to pull on the throttle cable housing, pulling it out of the stop-seat, and causing an uncontrolled throttle acceleration/response.
Video, compliments Viscious Cycles, Utah.
Adjust harley davidson throttle cables Video ? 5min.com