I really wished every noob would read this link below. Unfortunately people buy these engines and after they have problems they jump on the forum. We preach about stickies and the need to read them. We have learned from experience what can and what will go wrong with these cheap Chinese engines. Just doing a search will bring up a post or two of mine and others. I had a guy call me (not a member) and was having problems with his build (got his running), so I know it's out there. Had you come across this a lot of your problems could be alleviated. Sorry for your bad experience, but MAYBE others will take the recommendations, although it's too late for you at this point on your original engine.
As far as the engine shifting, I made this mod to keep that from happening.
Looking back, here is your problem,.....
Originally Posted by young grease monkey
I got a solid 30 with no mods
, but I do have the angle fire head and cns carb. I'm 150 pounds