REAR SWING ARM

[0T02G]

Looking at switching to a spoke rim with manual drum brakes off a older xs650. Mine right now is a aluminum disc set up. Will the swing arm from a manual drum fit where it connects to the frame (main pivot) and Correct me if I'm wrong that there are different swing arms for drum vs disc?

Thanks

 

[gggGary]

Yes they are (minor) different but they are a direct swap- perfect fit. The 70-73 are shorter and narrower so best to stay away from those.

 

[XSLeo]

The only difference between a drum swingarm and a disc swing arm is the location of the mount for the brake strut. On the disc it's on the top of the swing arm, on the drum it's on the bottom.
The brake pivot shaft is different too. The drum brake has a longer arm on the inside that pulls on the rod to the brake.
The disc version has a shorter arm and pushes up on a rod to the master cylinder.
There are differences in the mounting of the brake light switch as well as the pedal hieght adjuster.
Nothing to hard to do just be aware it's not just swapping the wheels.
You need every thing from the pedal back. The pedal is the only part that works with either set up.
I did just the opposite on my 75, went from drum to disc.
Leo

 

[0T02G]

The spooked wheel and rim I have must be from a older bike , because when I set the rim and tire in the swing arm I have at lease a 1" spacing diference.

Thats what brough me to my question.

Thanks

 

[maynard911]

From your initial post it sounds like you are saying that your swingarm is aluminum, if so it's from some other bike. Pictures please.

 

[gggGary]

If your spoke rear wheel has an 18" steel rim then it would be from a 70-73 XS Those use shorter spacers and axle than the later bikes. The 1" diff is about right. Early arms also have the shock mounts closer together.
Or it could be from something else entirely.

 

[XSLeo]

The difference in width between the 70-73 swing arms and the 74 up arms is that the earlier arms used 1/4 inch thick axle plates, the later 3/8 inch thick. The thicker plates used a longer axle. They are all 8 1/4 inches between the axle plates.
The early arms are shorter, not sure on the difference, I think it's 1 inch.
The difference between wheel bases is, older 55.5 inches, later 56.5 inches. This was all in the swingarm. A 1 inch difference.
If you wheel with spacers is an inch narrower then your wheel isn't an XS650 wheel. How many bolts hold the sprocket on?
Leo

 

[gggGary]

Would you believe the truth lies somewhere between Leo's and my posts? The RH side of the early (70-73) arms is narrower. You can see the difference in the RH spacer and the RH shock mount. They are about 3/8" narrower than the later arms. The axles are about an inch different like Leo says because the later axle plates are thicker also.

Yes I checked all 4 years of early swingarms.....

Early Late



Early spacers are on the left



Early LH shock mount Early RH shock mount.



I just noticed that the 79 axle is in backwards. I swear the PO did it and I just haven't changed it back yet.