Okay, thanks again for that input, I'am not sure what a 45 magnum is but I can look it up. Your comment about a properly set up pogo seat is exactly what I'am looking for.

 

45 Magnum is a 45 lower end and Ironhead Sportster top end, interesting creatures.

I completed a cross country trip in September on my 45, maybe once in Oklahoma a set of shocks would have been a good idea. 99% of the time the pogo did her job. Colony sells heavy duty springs to allow you to dial it in to your weight, I recommend. I have never bottomed out since changing the springs. Wash board surfaces mess with the springer front end more than the rigid rear.

 

there are a couple of firms making a hard tail frame for a 45 that use a 4 speed big twin transmission, but if you want a swingarm frame I'd start with a shovel frame and alter it,
the motor mounts at the bottom have i believe the same front to rear distance ,
the front lower motor mount also is lower than a big twin frame so you need I THINK a 1 inch thick block spacer on the front to raise the mount point. but the bolt pattern is also differant,
the other way is to build or have built a one off bespoke frame for the parts you need,
I have built many 45 based customs & found fitting a Commando clutch & geatbox is a good way to go or a Triumph boxalso works,
you dont need a trans as big or strong as a big twin trans on a 45,..
​​plus to aline with the transmission the motor has to be mounted way far to the left of the frame for all the primary & final drive to fit, this tends to unballance the bike as most the motors off set to the left,
this is a pic of one i built 30 years ago not a great pic but you can see the commando box,.
also a 45 Magnium is a 45 bottom end fitted with a 900 sportster top end, this is one I built a few years ago,

 

Thanks for all of that Magnum 45 Pete, I appreciate your photos and write up and a very nice job done to that bike build.

 

Thanks for your trouble Architect. I have a 1977 Ironhead in a softail frame that I bought in 2017 and has sat in a warehouse in Detroit ever since, I'am a Canadian guy who has not been able to get over there to bring it across yet, it's a long story why. I do a lot of looking on the internet for bike stuff and I have never seen this done before, but I'am sure it has been. I was told by the people I bought it from that the frame was a pauncho. I don't have a real good photograph of it but if I can send it along to you I will.

 

Long ago and it did not take off the sporty softail - cool idea but expensive with no hope of a return on investment

 

You're saying Harley Davidson tried this in the past sometime?

 

No paughco built them but they died on the vine

 

So I might have something quite rare here then.

 

An appraiser said to me once "rareness and desirability are two different things". I never forgot that.