Power Loss

[Sniper]

Ok, I've searched around the site, and I think I have an idea of where to start, but I just want to make sure I'm on the right track and get any information/pitfalls that I may need/run into.
I just bought a 1982 GS850L with 30K miles. It ran good for the first week (and first tank of gas) with some poping in the exhust when I throttled down (which I think means it was running lean). After the first week I started getting a missfire, and then one day it died on me while throttling down to stop. Now when I roll on the throttle I don't get the same acceleration and the engine bogs down (yet still accelerates) and I get the same problem when I roll on the throttle at higher speeds. The bike also has a slight vibration which it did not have before (wondering if one of the cylinders not firing could cause this). I plan on changing the plug wires (I already changed the plugs and checked them after change and found the number 2 cylinder has foulded after 20 miles of riding) and cleaning the carbs. Is there anything else I should look into? Any suggestions would be greatly appreciated.
Thanks.

[Sandy]

If you have the stock fuel petcock it is mostly likely the problem. It is operated by a vacuum line connected from the petcock to the number 2 carb and if the diaphram in the petcock is leaking it will suck fuel into the number 2 cylinder. Simply unhook the vacuum line and if it is wet with fuel that's your problem and a fuel petcock repair or replacement will be in order. The leaky diaphram will also cause the petcock to not open fully and restrict the fuel flow, this could also be your bogging problem.