HarleyTechTalk

On FXR/FLT models the same parts fit 89-93 or 94 and up. Is there any difference in the mainshaft spline count? Trying to put together an updated drive train for a friend with an 86 FXR. It's easy to change the inner/outer primary bushings, jackshaft and ring gear if the clutch baskets are the same. I also know that we have to be careful with the engine sprocket tooth count to the tooth count on the clutch basket to keep the gearing correct. That can all be changed if needed. Lots of cheap TC parts out there to be had.

Thanks, Buddy....

 `89 and earlier used tapered mainshafts.

Splines are the same for`90-up mainshafts on 5 speed transmissions.

The `90 mainshaft is the oddball, it was only used one year, the first year of the splined mainshaft. It will not fit `91-later gearsets.

If you have an `89 or earlier 5 speed transmission, and only want to change the mainshaft to upgrade to splines, the `90 mainshaft is the one to use, as it will fit all the earlier 5 speed gearsets, however, an entire gearset from `90-`99 will drop right in the case ( I used a 1999 gearset in my `89 Softail).

The `91-up 5 speed mainshafts were made beefier, and the gears are different also.

In `98 the trapdoor and its bearings changed, the bearings have a larger outside diameter, but the inside diameter remained the same, as did the shafts. A `98 or later 5 speed trap door with the bigger bearings will work fine on an older transmission, plug and play.

`90-`93 Clutch outer shells have the same primary and starter gearing as the earlier models that used the tapered shaft. 37 tooth primary sprockets, 66 tooth starter ring gear.

`94-`97 outer shells have 36 tooth primary sprockets (can`t remember the ring gear size).

Inner clutch hub is the same for `90-`97.

I hope some of this makes sense…

It made sense to me.

If you go with the 98 and later gear set on the door of which there are many with everybody goin to 6 speed trannys, and use a inner primary with a - 94 part# for FXR you can upgrade to an all TC primary and starter setup. For a final drive ratio of 3:37 you will need a 37 tooth clutch basket which most of the injected touring models have. You can also use the inner primary with a -99 number for the FXR 2,III's and IV's just make sure you have the hole for the shifter linkage.

I had a buddy who had the 94-later inner primary and decided to use the Twin Cam outer primary (with the 5-screw derby), and he had starter issues.  Put the Evo part on and no more starter problems.  Some kind of jackshaft problem.

You have to use the later jack shaft that works with the tc starter also

First thing we need is a later model FXR/FLT transmision case, the rest can come later. Thanks for the replies and info.
Buddy.