Cracked inner primary is obsolete

[Lowbrow88]

Hi
I have a 1988 flstc with a cracked inner primary (60630-86A) that is obsolete and unobtainable as I've searched for over a year now. My question is if I can use another primary like 90-93 softail with my evo and 5 speed? If so what do I need to know besides changing the starter and cylanoid?
Any help appreciated.

[Sky]

Nope
Get that sucker welded up
And figure out why it cracked, so it don't happen again

I mean yes, it can be changed, but you are looking at swapping trans cases, main shaft, starter setup, rear pulley/sprocket, clutch and so on...
Actually all of the above would be upgrades so

[BuddhahoodVato]

Get some of that aluminum weld, that you use with a plumbers torch.

[farmall]

Those primaries are known for cracking. I'd have it TIGed properly if you don't upgrade (I'd upgrade!) since the aluminum brazing rod isn't weld and primary covers take a good bit of load. A weldor experienced on sand castings should do the work and the primary should be securely clamped to a smooth welding table to prevent warpage. Inner primary covers warp/"hot short" easily.

I'd replace the transmission,clutch and primary covers with more plentiful later parts. I did similar on my FXR (different length primary, otherwise same problem). Well worth it. The later starter is considerably more powerful and can take the useful aftermarket pushbutton end cover. The splined shaft transmission makes clutch R&I much easier and offers greater aftermarket clutch choice.

Use the Ronnie's HD online parts books to get smart about part numbers and search them on Ebay etc. Most used Denso OSGR starter motors just need a contact kit (cheap). Twin Cam transmissions won't swap because the case is different.

What I did was buy a used transmission then got the factory service manual and parts book for the transmission year.