I have a 2007, foot shift. It shifts fine from 1st to 2nd when I'm driving but if I want to shift to 3rd i have to stop and shift up. Same with 4th and 5th. Any help with a diagnosis would be appreciated.

 

Check the clutch is adjusted properly but it is probably a problem with the selector mechanism. If clutch adjustment doesn't fix it, remove the clutch cover and check the selector mechanism inside for broken springs, cracked or broken levers and that the star wheel on the end of the shift drum is not loose. 420s are a lot less prone to selector problems than the 350, but it can still occur. If all is well in the clutch housing, check the multiplate clutch, but it is probably be a bent selector fork or worn shift drum. The only way of checking that is a complete engine stripdown.