Well I put it all back together last night and went for a test drive. So far, everything seems to be working as it should. I don't appear to have any leaks or weird noises, so that's good. I'm running a premix of about 40:1 this time to protect the engine, but it's still crazy to me how it doesn't seem to smoke at all. I couldn't get a block off plate, but I did find a spare check valve and installed it. This one initially tested fine (popped open when a small vacuum was placed on it, sealed up otherwise. However, I still don't appear to be getting any oil out of the tube that goes to the carb. I opened the bleed screw on top of the pump and oil was running out, so I don't think I've got air in the system. Obviously if I'm running premix I don't need the oil injection system, but now it's really my own curiosity wanting to know what went wrong on this system that took out two motors.

 

Hi, just catching up on your progress. Sorry to hear about you engine. When I put everything back together, I was worried about the oil pump as well. Ran premix for the first couple of hours but before I connected the oil line to the carb, I ran the bike at idle with a small zip lock back over the hose and manually pushed the oil pump to to the max. I could see the bag filling with oil, so I knew I was good to go before I connected the hose to carb. I'd give this a try if you are still concerned.