I had to buy a new (used) final driven flange and final driven gear assy. I also bought a wheel to go with the flange because I bought a very nice '84 flange and my bike is a '86.
I read a lot of posts about what fit what, some were contradictory to other posts so I thought I would research myself.
Some said '84-85 pin diameter was different from '86-87, wrong - no difference in pin diameter or in pin circle diameter. the only difference is the pins in the '84-85 are about .050 longer than the '86 -87, not enough to matter.
I found some wheels online shown as say '85 were really '86-87, I don't think they are purposely misrepresenting the parts, I think someone may have changed a wheel/flange at one time and the guy parting it doesn't know the diffrence in years. Because of this I thought I would share some info that I hope will help keep people from getting wrong parts as they are needed and used is all there is.
You want to keep flange and wheel matched by year for them to work, ie: 84-5 flange with 84-5 wheel.
First off, any final driven gear assy from '84 to 87 will work on any '84 to 87 bike.
The '84 - 85 flange has a longer center bore and is smaller I/D than the '86 - 87.
The wheel for '84 - 85 has the hub turned where the flange slides over, the '86 - 87 does not have the hub turned.
(Just a side note....the driven flange from the '88 - 89 1500 will work on the '86 - 87 wheel)
Below are pictures that I think will help understand what to look for when buying replacement parts.
driven flage for '84-5, note long center
driven flange for '86-7, note short center - ('88 -89 flange is same)
wheel for '84-5, note turned hub
wheel for '86-7, note hub not turned
I hope this helps some of you some day, I know I had a hard time finding any definitive info.
I'm glad I found nice parts, it payed off nicely as you can see below