First of all the wieghts are made from steel.
"I'd like to add a weight too, but don't feel like spending $150. Can anybody give me the thicknessso I can make my own (I assume we're working with aluminum)? I'm thinking $30 for something turned to my specs would be reasonable. Any help would be appreciated."
The weight I installed for a friend included the weight, misc. longer bolts, and a spacer to space the ignition cover out enough to provide clearance for the weight.
I suppose you could make your own by welding a stack of tuna can lids to the flywheel and using 10-15 side cover gaskets to create the space. Thirty bucks ought to about do it.
Second, side cover gaskets run around 8 dollars each. 10 of them would be 80 bucks. Making your own flywheel weight is not that hard if you have a lathe and a mill. However making one out of tuna can lids is just plain stupid.You would never get it balanced properly and that is if you could even get enough weight to make a difference.