I have a 1986 soft tailr custom it is the first Harley-Davidson I ever owned with a starter motor. I need to know what the eastiest  way  to put a new starter motor in. do you need to take the inner and outer primery  off or can you do it by taking the oil tank out

never worked on anything HD that far back but, I did change the starter on a 1996 softail a few months ago.
What a bitch of a job. Remove battery, remove pipes to get to bolts to remove oil tank, remove outer primary, remove clutch hub then you can get the starter out. Also had to replace the starter drive gear.
Would strongly advise getting a manual if at all possible.
I fitted an Allballs starter, shop around for price what ever brand you go with

 as long as you have the bendix thro - out fork in the pri  or you might have to take out the oil tank to put the fork & tapered screw ,  the screw goes in thru the top of the inner pri , other wise leave everything in place,   it would be more easy with the bike up on the lift stand as you have to work up under the oil tank , but on the other hand it's a good idea too pull the oil bag out & give it a very good clean inside you never know what you might find , hopefully nothing

 if you just want too take out the starter motor only it's easy you just take off the outer chrome cover  then the 2  long studs norm are 5/16'' hex head make sure you take the starter motor out as a unit   it can full apart in 3 sections