Fitting Cast Wheels
I have recently fit cast wheels to my Berg and can be of some assistance on the subject. Firstly it is a pain in the ***, and probably won't end up as cheap as you may think, unless you work in a machine shop.
The first mistake that I made was not to buy wide enough rims, the front is 2.5 and the rear 3.5, I thought there's no way that SM bikes can be running way wider tires than 1000cc sportbikes from a few years back - wrong! The good news is that I can run the sizes most use 120 at the front and 150 at the back. The bad news is the profile is compromised by being squeezed by the narrower rim. With the sticky tires I have, it seems to work well enough though.
The project is a low budget supermoto race bike for an entry level racer. So aesthetics were not my primary concern - just as well as the wheels do not match. However as they are both three spoke, have a polished rim and are painted the same color, the differences aren't too great.
The front wheel was easy. I took the stock front wheel and the axle to the local bike breakers and rummaged through their stock until I found a 17" wheel that the axle fit into, had one rotor, and was approximately the same hub width. The wheel is from a Kawasaki 500 Eliminator, cost with the rotor was $50. The wheel fit into the Berg with filing two groves into the caliper bracket.
The rear wheel was very difficult. I choose a 87 Honda CBR 1000 rear wheel. Cost with sprocket, cush drive and brake rotor, $100. So far so good. The cush drive makes the rear wheel very wide, I did want to keep the cush drive as it helps cut down on chatter, which was a big problem with the 18" rear wheel and street tire that I was previously running. I marked on the wheel how much needed to be machined off of the cush drive side, so that the sprocket would align, about an inch. On the other side I had to measure how much had to be removed from the brake rotor mount so that it would align with the brake caliper.Then I took the wheel to a machine shop to cut off the excess material. Cost $90.
I choose to retain the large brake rotor that came with the wheel. This required adding an 1 1/4" to the rear brake caliper bracket. Aluminum welding is very expensive apparently, cost $150 (note: I may have been ripped off a bit )
Because everything is really tight I had to grind down the bolt heads for every sprocket bolt and rotor bolt - this took several nights.
The stock axle is retained, but new spacers had to be made out of used ones from the bike breakers.
Sportbikes use the larger 530 chain and sprockets, although 520 sprockets for road racing are available for the more popular models, I am using the 530 sprocket that came with the wheel, so I needed to buy a 530 chain, cost $100.
Anyway, this gives you an idea of some of the issues that you will be facing. Good luck.............
For Bike photo see
http://www.husaberg.org/uploads/BergRyd ... %20008.jpg