A common upgrade on sportbikes is to replace the stock rear shock with an aftermarket shock. On this Yamaha YZF-R6, we discover that one rider has replaced his shock and added a heavier spring. The pre-load, however, was not adjusted correctly for the new spring and the bike was riding on the top-out spring. Dave Moss and Jim Williams of Catalyst Reaction Suspension Tuning are on location at an AFM race weekend and manage to help the rider out. Be sure to check out other Roadracing World feature videos. Video provided by ~http://www.OnTheThrottle.tv~