Shims for crank and clutch shaft, where can i get them?

Where can I find the shims used on crank shaft to prevent the crank from back and forth movement inside of crankcase. The shims are also on the clutch shaft behind the chain ring and the clutch gears. I have purchased almost every spare part for me engine that you can think of from allot the companies that have there links on this website but never found any that sell the shims that go on the crankshaft and clutchshaft?? Please let me know where I can purchase these shims. Thankyou my fellow motor bicycle enthusiests Thomas J (Choco Dog)