Anybody got suggestions on how to get my belt to ride all the way up on the primary [@ 3/8" now] and minimize belt slippage?

The sled is stock, clutching gr.bu. spg. 200-290, 295 ramps, 18.7 gr. pins, #3 clicker. Secondary with beige spg. @ B-6 21#. 50/47 helix, Gates extreme belt. My r.p.m."s are perfect,
she slaps 8200 and climbs to 8300 max. Seems like the clutches are to hot indicating slippage and I weigh 235#. Any ideas?