there are slipper clutches available for a lot of race models but you still need to use the clutch to change gears. they arent cheap either, but i dont recall seeing any for a 250x/300ex motor. as for an auto clutch conversion since the crankshaft and cases are different than a regular 300 that conversion is out of the question. the only quad honda makes that has a trainer clutch (can use the clutch but not necessary since it has an auto clutch as well) is a trx250ex.