| How often are you checking the spokes for tension? Spokes shift and you need to check them periodically. riding hard and Dyno runs make this more of a problem.
Make it a habit to have the spokes tweaked at EVERY tire change at the minimum.
You are most likely experiencing the old bicycle thing where one spoke loosens then the next then an opposite side and next thing you know, you are on your but with a goofy looking wheel.
Torque induces a rotational twisting motion so spoke are being stretched while under hard acceleration. The pressure is applied from the left side and the pulley is trying to pull forward. So these spokes would get more strain than the right side. Get one loose and it is the same thing as a bicycle. | 
