Hey. I'm a newby at this. I have a regular stock 80/66cc engine and a stock carb. I installed the kits and it ran really really good for about two days. Now when I start the bike it turns over no problem but when I twist the throttle I rarely get a reaction sometimes I get a reaction when I'm moving a bit faster it feels like the bike is is jumping or jolting In-N-Out. I completely took the gas tank and the carburetor off drained it of all its fuel make sure there's no clogs anywhere or debris anywhere we filled it with gas and two-stroke oil at the proper ratio and still the same reaction the bike starts and if I pedal while using the throttle it feel like it wants to go. Today it ran perfectly it's time for about 15 minutes and back to the issue I was dealing with. As of right now I took the spark plug out and the bottom of it is like black I did have some oil leaking out of the tailpipe I've also remove that I've tighten all the bolts to make sure I have no air leak I still have the same problem so the bike is starting and it's staying on as long as I pedal it and when I left the choke it stays on as long as I'm pedaling it. I have no clue how to fix this issue this is the third engine that I bought the last two got stolen I'm putting out a lot of money and I getting a lot of satisfaction out of these things somebody help