I have a Blitz 500cc and have owned it for about 25 years. Re the chain oiling problem: I had this problem too. I found that the outlet from the oil tank to the chain pump is covered by a piece of gauze. I got a small globe and soldered it to a couple of wires and then connected them to a battery. When I dropped this into the empty oil tank I could see that the gauze was covered with a layer of hardened sawdust. I made a little tool to scrape this off and then gave it a good wash in kerosine. This fixed the problem.
I now apparently have a big end problem because it won't start and makes a lot of noise. One day I'll pull it down and try to track down the problem. I bought a second hand Stihl 320 and had a lot of trouble getting it started. I found that the choke MUST be closed tight to get it going. Had to bend the connecting wire a bit to make this happen. This is true of most two stroke engines. Hope this helps.
damac
December 2008