Topic: 1978 CB750k trying to run comstars

[vinny9744]

Hey everybody, I just picked up a 78k on the cheap. It needs lots of work, but has a clear title. Among a ton of other things the rims were almost non existent do to rust, having been left outside for a looooong time. I know they're not very popular but I've always liked the look of mag wheels on later bikes. So I picked up a set of Comstars from a 78 supersport. This means switching to a rear disc as well. For the back I obtained the swing arm, rear disc, caliper and rear axle. For the front, all I have so far is the rim.  I was planning on switching the parts over from the existing front wheel but just realized the Comstar uses a five hole disc.

I want to run this Comstar rim for the front but need to know which disc rotor to get.
I think this rim was supposed to go with dual discs, but can I just run one?
As I just want to run one caliper, can I use the one from my 78k?
Does the Comstar need a different axle and spacer?

I'm sure I'm forgetting a bunch of stuff but any help is appreciated.
Thanks

[Bankerdanny]

You might see if you can track down a 77-78 F front end including the triple. Then it's a direct bolt up and you can keep the twin fronts.

I think the axle size is the same, but you may need a spacer on the side without the disk.