I have a 1997 Vulcan 1500 Classic D2 with the 4 speed transmission. Over the past week the transmission is jumping out of 2nd gear just about every time I shift from 1st to 2nd. All the other gears are fine and when I downshift from 3rd to 2nd it holds ok. It did this a couple of time back in the spring but now it is almost every time. The bike has 62,500 miles on it. Would this be a gear or synchronizer that would be causing this and how hard to fix??