OK, as you know the throttle is spring loaded to close it automaticly. You can likely do a very quick fix to your problem. Between the end of the throttle and the hand grip there should be a thin plastic ring. This is to help the throttle porsion of the grip to slid freely on the outter part of the grip. If the plastic is missing you will need t oget one. If it is there you will need to adjust the location of the throttle on the handle bar. There is a small METRIC set screw on the area of the throttle under the battery lights. Loosen this screw and move the throttle over. Be sure the outter hand grip is pushed on the bar as far as possible. Leave a 1/32 to 1/16" space between the 2 grips and retighten the throttle set screw. You should be good to go with no sticking. Of course you can always just slide the outter hand grip off a little but I don't recommend this because it will move right back again.

Bob