TORS

[mark the shark]

Is the TORS light on the dash coming on? If the thumb throttle on the handlebar isn't operating properly it will cause symptoms like you have. Sometimes it takes a little shot of silicone or teflon spray to get it loosened up.
http://www.vmax4.com/vbulletin/../files/tors1.jpghttp://www.vmax4.com/vbulletin/../files/tors2.jpg
Shark