G2 makes throttle cams with different profiles:
http://g2ergo.com/shop/catalog/Street-4-1.html. Some of the cams make the throttle opening faster and some make it slower:
http://www.cyclebuy.com/shopping/g2/g2_ergo.htm, but it's still 1/4 turn. It's been over two decades since I've been on a track, but throttle control is super important on twisty mountain roads. The cam for the FJ1300 seems to work very well:
http://www.webbikeworld.com/r3/throttle-cam/.