Suzuki 2 Strokes

Ok, so I'm a pretty new here, but have been lurking around a bit and haven't found anything like this yet. I picked up a '75 Gt 550, and then had to pick up an engine from ebay. Put the engine in the bike cleaned up the carbs checked over the points and set the gaps, checked compression and finally got the engine to start. Took the bike up and down the street then pulled into my drive way and cracked the throttle. As soon as I did this the engine went wide open, throttle was closed, I hit the kill switch, engine still full throttle. I then turned the key off, engine still full blast. I then started pulling the spark plug wires from the plugs and still engine redlining. It did this for about 60 seconds or more with no spark until I think it ran out of gas. Any thoughts?

I know lean condition and ignition advance may have something to do with this. But I've never seen it happen this bad.

Excessive carbon deposits used to allow a motor to run for a while after the sparks were shut down, but I've never known anything quite as dramatic as that

Pull the heads and de-carbon the pistons, heads, pull the exhausts off as well to clean the exhaust ports. Might need to pull the baffles too just to check them.

Could have an air leak also...

so im probably the least experienced of the bunch here. ive got a 74 that was having an issue with the idle screw unscrewing from the engine vibration basically holding the throttle open. takes like 2 seconds to check thought i might mention it. heres a video http://www.youtube.com/watch?v=DzZp4vue_lE" onclick="window.open(this.href);return false;