I´ve got a bad braking problem with my 2003 VMax (stock) except for Avon tire on the rear. I´ve had shaft drive bikes before (Honda V65) but none of them did what this VMax does. When I make a panic stop, with the rear brake locked, the bike´s rear tire slides viciously from left to right and back again. It does this until I come right to a stop. On my V65, a locked rear brake would skid absolutely straight. I run into this when accellerating quickly too. Crack the throttle wide open and the tire breaks hard left first, then overcompensates to the right. If I don´t let off the throttle, it just keeps on doing this. I´m worried that something is wrong. Something dangerous. This is a fairly new bike. Any ideas what to look at as a cause?