It heats that clutch up even more I'm sure. Heat is the killer of centrifugal clutches. Burns the oil out of the bronze bushing, and using it as a brake creates torque on the bushing and the fiber spacer. Causes premature wear of the clutch. Jim Donovan (Max Torque) doesn't like the idea, and has commented on it. They do stop good as long as the chain doesn't break, and are an easy remedy for otherwise difficult engineering problems with the rear axle and a brake. Ruttman used them. Plenty of vendors sell kits for them.