I picked up an 05 quad sport 50 for my son a month ago. When I bought it, it wasn't running and I was told by the seller that it was a dirty carb. I should have known better(lol). After cleaning the carb and it still not running, I checked the compression and it barely registered 70lbs. I orderd a piston kit and had the cylinder bored .020 over. Once I got her back together, I started to wonder why it may have fried the rings in the first place? Overall the quad is in great shape so Ive started to second guess the oil injection?

At any rate I left the oil injection in place, and also for the first tank of fuel decided to run some 40:1 premix. It runs great but also seems to smoke more than it should. After running the first tank of fuel I noticed that the oil in the tank didn't seem to go down at all. VERY little if it did. With that said, I removed the tank, and plugged the oil line with a very tight fitting bolt and a couple zip ties .

Did I make the right choice? Did I do what need to be done to block off the oil injection? And if so, what mix ratio should I run in it? Thanks in advance.

 

I think you made the correct decision.
I don't know about disconnecting the oil pump.
I'd run 32:1