can any one explaine exactly what a syncroniser does. this is on a 49 3100 3spd. i try to put it in gear and it sounds like it's not engageing fully. i have had the shiftdoor off and it hits all the detents properly and is assembled exactly like the book says. with the shift door on the trans i can feel each fork fall into its detent position. still alot of noise and wont go any where. i am wondering what part the syncro plays here.
thanks,

Old Harley Mechanic