Motorcycle Repair: 1974 sportster transmission shifting problem, moving down the road, side shift

Question
Hi I have a 1974 right side shift sportster that has a problem going into 3rd and 4th gear...I had ridden the bike a few times and it went into gear fine other than the sloppy feel from the aftermarket forwards, but it did go in fine no grind and was smooth thru 3rd and 4th.. I know the main shift shaft crosses over from the right side to the left  but I've never had the primary cover off so I dont reall know how it all works . Am I going to have to disassemble the clutch and flywheel set up to get back to the shifter paw? and is there a common problem with the shifter assembly ie: roll pin, adjustment ect...? last thing  also in the trans or clutch area I have a mystery slip and grab under heavy load. I can be moving down the road really twistin on it kinda hard and it will "pop" kinda into a neutral stat for a sec. and the pick back up righ where I left off????

Answer
Hi Scott,
This is whats called 3rd gear centering, and i appologize, but this is something that a H-D tech should really dig into. What happens is the shifting forks become "mis-alighned" Making in difficult to get back to those gears.

What I might try 1st, is if its at all difficult to find nuetral, try snugging up your primary chain 1st. It should have about 1/2 to 3/4 of play in several different places with the rear wheel off the ground...

Hope this helps!

~Mark Panka