Motorcycle Repair: CB360T lost compression on left side, 1975 honda cb360t, adjustment screw

Question
I have a 1975 Honda CB360T with 15k on the odo. that was in OK running condition (started up cold after 10 seconds or so, idled fine--after carb adj.--plenty of power, both exhaust had equal output, etc). I went to start it the other day and it was doing this popping noise near the left carb and backfiring on the left side. It was idling but not smoothly. The output from the left exhaust was very low, but noticeable. I had gotten the idle running almost perfectly a day or so earlier, so I thought maybe it had to do with starting cold and the adjustment I did. So I tried to adjust the left carb again, but the adjustment screw did nothing. It is as if it is completely bypassed. I put new plugs in it one month ago (NGK .28 gap). The gas tank is also very rusty inside and I am going to replace it so I am letting the fuel supply get low. Probably not a good idea since the rust may gather near the petcock when this happens. Does this have anything to do with rust possibly getting into the carb? I have not rebuilt the carbs either. To my knowledge they are all original.

Answer
Corey,
-possibly the rust has plugged
the fuel line or the fuel inlet needle valve
in the carb. Try draining the float bowl,
see if gas flows through.
-You may need to clean the carb jets also.

-If it looks like the fuel is okay, check your
contact points as they may not be opening.
Set them around .014" - .016"
-Points should just break when the "F" mark lines
up down below on the engine rotor.
-You can do a compression check to
see if the cylinders are near the same pressure.