1978 rear end on a 1975 xs for a disk conversion

[JNizza92]

Hey guys,

I have a 1975 xs650 that I am converting to a cafe/street tracker and I have recently came upon a 1978 swingarm, rear caliper, master cylinder, front and rear mag wheels, and all the hardware that goes with it for very cheap.

My question is this: will the 1978 rear end bolt right into my 1975 frame, and will the from mag wheel work?

The 1975 is the spoked wheel setup, from the messages me and selling have been sending back and forth it looks like this swap will be a no brainer and will bolt right up with no issues but I want some input from some other xs650 gear heads.

Jordan

 

[650Skull]

With what you have it is an easy swap. If you can get hold of the bracket that holds the M/C reservoir on it would be good, ( the guy you are getting the gear off of may still have bracket in the third pic), and all you need to do is weld on the lugs to hold the M/C, 1st and 2nd pic

You will have to swap over your 75 front disk to the mag wheel for it to work with the 75 front forks

 

[JNizza92]

the guy may still have the rear part of the frame, I am not 100% sure though, he used the frame as the start of a hardtail project.

Assuming I can not get that bracket in the 3rd pic and those 2 little cylinders from the 1st and 2nd pic, is there an easy way to mount the master cylinder without those?

The pictures helped alot! thanks

The picture is what that area of the frame looks like on my bike.

 

[XSLeo]

If you want to mount the master cylinder then you need to weld mounts on. I did to put the disc brake on the rear of my 75. I used a 79 swingarm. Bolts right in. The only difference in the swing arm is where the brake strut mounts, the drum is on the bottom, the disc is on the top.
A lot of work, a better brake. Worth the trouble. Not really. I won't do it again.
Leo

 

[JNizza92]

So all that needs to be done is the mount for the reservoir and the MC welded on? Those 2 little cylinder things need to be welded on the frame about where the foot pegs go for the MC and the bracket for the reservoir goes right next to where the side cover clamps on, well it can go anywhere above the MC correct?

 

[650Skull]

If you are using a swing-arm off a disk brake bike then there should not have to be any changes made to it, bolt on and go.

To save any confusion then state if the 78 swing arm is from a Standard=drum or special=disk

The cylinder lugs can be made out of any tubing and welded on, getting the reservoir bracket, even if the plate was cut bad taking it off, you would be able to make another

Placement of the Reservoir bracket may depend on what you are doing to the bike.

 

[XSLeo]

Yes, the reservoir can mount anywhere above the M/C. Some just use a long clear hose as a reservoir.
welding the M/C mounts to the frame needs to be done right. Too far up the angle of the frame and the adjustable push rod will be too short. Use the pics in 650skull's post to help locate them right.
Leo

 

[JNizza92]

I did the conversion over the weekend, the whole thing from mockup to finished product took 2 hours, it was very easy and simple to do.