My wheels are rear from Honda motorcycle from a CB 350. They are similar in the CB250 and CB450.
This is how to modify them for use on an
Air Camper. (see picture above for clearer drawings)
(see picture above for clearer drawings)
Remove the ball bearings from wheel and discard after measuring the outside diameter.
Make bronze bushings (4) with the same outside dimension and width (add 0.05 to width) as ball bearings with an inside dimension of 1.5
These bushings should be a press fit into the hubs like the original bearings. They should be slightly proud of the wheel when installed.
Modification to Wheel
Remove the spokes from the wheel rim and hub. Remove the sprocket nut and sprocket.
Install the hub on a lathe and remove the threaded piece that holds on the sprocket. It is a steel piece that is cast into the aluminum hub. All the steel is removed but be careful here. You are facing this hub so the bearing cavity is the same width as the bearing cavity on the inside of the hub.
This step can be done without a lathe by hack sawing the steel piece off and filing or grinding the hub so the same dimension is achieved as above. As long as when the bearing is installed the bearing is slightly proud then the job is done.
Cut off the casting lobes from the inside of the hub with a hacksaw. This will be obvious. Reassemble the hub and rim.
I used a 18 by 3 tire with about 45 psi air pressure. Your rim may be different as some of them were 16.
Modification to the brake plate (see sketch)
You will need to make four aluminum collars to fit on the 1.5 axle. I used 2.5 O.D. by 1.5 I.D. aluminum pipe and they are about ½ wide.
This pipe is commonly used as scaffolding tubing and is 6061-T6.
You will need to make two transition pieces for the brake plates from the same material. Dimension as needed below.
First remove the brake shoes and hardware from the brake plate. Install it in a lathe and bore a hole the brake plate just slightly smaller than the outside diameter of the aluminum pipe. Face off the feather edge enough so you can later weld this plate to transition piece.
Now machine some pipe material so it is a slip fit with the hole in the brake plate. There needs to be a shoulder on this piece so the piece projects through the brake plate to the same position as the unmodified brake plate did. In another words the transition piece must hold the brake plate in position in the same position as before with the smaller axle. This takes the side thrust and prevents the brake plate from contacting the wheel.
Once the step is done the transition piece can be parted so that ½ of the transition piece projects out of the outside of the brake plate.
Put the pieces together and carefully align. Weld the transition piece to the brake plate.
Drill out the hole in the brake plate to ½ where the anti-rotation arm attached. Install a piece of heavy walled steel tubing with a hole to attach a cable.
Cut off the brake lever and drill a 3/16 hole in the end. The lever needs to be only about 2 long!
Braze one or more small but thick pieces of steel to the axle to prevent the inside collar from siding inward. This is better than drilling a hole in it. Dont fret about this the bungles tend to push the brake plates outwards
Install the inner collar, the break plate, the wheel with bearings and the outer collar. The outer collar is bolted to the axle with a 3/16 bolt.
When installed the brake plate must rotate on the axle.
Anti rotation Device
Flatten an end of ½ tube and drill 3/16 hole in it. The flatten end will be bent slightly so that part is vertical when the piece is installed.
Install the tube to the front of the gear leg with a steel strap. File a small grove in the bottom ash piece to help it stay in place. Close off the top of the tubing.
Install a cable between the tubing and the brake plate tubing about 6 long. The cable is 1/8 diameter.
This looks Mickey Mouse but works very well. I wish I could take credit for it but I copied it from a picture of a Californian Piet.