HELP - Blown Engine or What??

Was driving around as usual and everything was fine. GPS'ed my top spped at 27 on a 66cc Zoom Bicycle slant kit. About 15 minutes in I noticed a red glow at the muffler and pulled over. Well, my muffler housing had fallen off so I was looking at just the inside of the catalyic converter or whatever that is inside the housing. I continued to drive and small flames came out the end of the muffler and the pipe stayed red hot at the entrance of the "now gone" housing. Amazingly the pick up was incredible and GPS'ed at 32 which was a 5 mile an hour gain. So i figured I would just order a new housing when I got home. But, about 1/2 mile from home the engine stopped and I could not get it started again. This engine only has about 25 miles on it so it is new. Is there any advice on what I should do. Obviously, I will wait till morning to take a closer look, but is there a problem running it without the housing? It was loud but ran like it really wanted to. Maybe it just overheated, but all of the issue was way down the exhaust, so I cant imagine it interfered with the engin. thanks.

I thought about that too an hour later and looked, nope still a half tank.

Well I was ready for all kinds of repairs when inspecting the bike this morning...just couldn't find anything. Then there it was. The little brass clip inside the spark plug cable that snaps on the end of spart plug had vibrated itself unscrewed. Tightened it back down to make contact with the cable and popped her back on the plug. She fired right up and rode great. Now if I can find my muffler housing along the road, she won't wake the dead driving by. Isn't an easy simple fix great sometimes!

Would like to see the pic, but it doesn't look like it attached.

I want to explain exactly what was glowing red. And yes it happened. It was night so it stood out. The shroud that goes over the last half of the muffler fell off. The one screw holding it on must have vibrated loose and thank God I didn't run over it when it came off. I was going full throttle for about 5 minutes when I pulled in a parking lot and noticed the red glow. It was about a 1-2 inch section of pipe right where the pipe off the engine meets the larger second half..bright red...also at full throttle there was a flame shooting out the end of the pipe about the size of a cigarette lighter flame. It was shooting out of the 3 or 4 holes at the end of the catalytic convertor part. Sorta looked like the flame that comes out of a military rifle on full auto. Looked cool actually but it was very loud and was heating up my anklepretty bad. Iv been driving it for the few days with the shroud off and it runs fine, although pretty loud. I may just replace the whole muffler because I can't find just the shroud for sale.