roots to a psi d

run 14 mm with great success on roots, switched to 8 mm gt 33 top used 65 bottom new , broke 3 inch belt on throttle wack. top pulley has a lot of wear on tooth profile.
what would best choice be switch to bigger belt 84 or go to 11mm or can you get 14 mm to work ,it might be a long shot but like to get the best parts first time around.
belt tension was about 3/4 inch

 

Belt wasn't tight enough ,when you wacked the throttle without a load the rotor weight is much higher on a PSI and the belt will climb over the teethe ,with the engine load it doesn't do that only on a free rev.

 

So here's a question........

What is the best procedure for loading, or pre-tensioning, an 8mm belt with a cold start engine?

 

Tighten belt like a bow string ,why I know I left the belt not as tight as it should be. and they were 14mm belts ,I wracked the throttle and did it twice ,and broke 2 belts ,I thought they were just old ,so on the third one a new one when it did it again it broke the front cover ,so I talked to JR at rbs and he told me about the rotor weight and the belts climbing on top of the teeth.So lesson learned don't just wack the throttle with no load two times in a row.PS also did this one time with a 8 mm belt.