I am looking for an old rear chain that will fit my '73. When I bought it as a basketcase, the chain was missing and I need to get my motor at TDC.

It does not need to be in good condition, I won't use it for anything else than to turn the motor over.

 

Just run down to the local tractor dealer and have 'em cut you off a lenght of 530 chain. I believe your bike calls for 106 links.

Or order one of these 20 buck cheapo's...

http://www.moto-chains.com/site/898528/product/ps530