I think I need to replace the starter

SOURCE: 1978 Electra-Glide Starter initionally catches,

sounds like the starter is bad. if access to it easy for you then it can be removed and taken to your local repair shop and rebuilt. Or try locateing one on ebay.

SOURCE: spinning starter

Your sprag clutch that kicks the starter gear into the flywheel is malfunctioning. I've ridden a bike for years with this problem, but when it stops working completely you'll have to push-start it! You'll probably have to split the engine/transmission case to get to it if you want to clean it. I have had success running CD-2 as described here. You might try that before tearing into the bike.

SOURCE: 1999 sporster 1200 starting prolem

sounds like starter is pullin' alot of juice away from the ignition..this can also happen if your battery is less than optimal...to test this try jumpstarting with donor vehicles engine NOT running...if she fires right up then try charging your battery fully and if still won't handle it, time for a new battery...good luck to you friend...Tim

SOURCE: installing new starter the bolt on the end spins

Hmmm! I'm trying to figure this one out but I'm not positive that I understand the problem. It sounds like you're saying that the bolt that runs through the starter jack shaft is backing out even though you've got the primary cover in place and the small locking tab bent over. If this is correct, it's a new new one on me. I've never seen this before. But, I guess there's lots of things that I haven't seen.

Anyway, the bolt should should be torqued to something like 7 foot pounds and I always put some Loktite 242 (medium strength blue) on the threads. Make sure the bolt is not broken off on the threaded end, compare it to a new one. I have seen that before. Also, make sure the jack shaft assembly is properly assembled. The "coupling" with the small circlip down inside of it goes on a certain way, tapered end into the starter.

Check the bearing in your outer primary cover to make sure it's not bad. Also look into the hole where the bearing is to see if the jackshaft is "bottoming out" in the hole.

SOURCE: I have a 03 Duce and it has allways had a hard

It sounds like u have a problem with the jack shaft. I would remove the outer primary and check to see that its still in place. u should be able to grasp the jack shaft with a wrench and pull it - and the spring will return it. My guess is its either come loose, or something is interfering with its movement