[BakedPotoato]

I recently rebuilt the top end and readjusted the valves yesterday on my Crossfire 150r. It runs great but I have two big problems. When I push the go kart it feels like the engine is trying to hold the wheels still but I can still move it with a lot of effort. When it's being pushed, I can see the chain shake every couple of inches I push it like the engine is grabbing it. I've tried changing the gear oil and motor oil, but it didn't help. My other problem is that when I'm driving the go kart and come to a stop the engine dies. I have to brake extremely carefully and slowly in order to keep it running. I think this may be related to the pushing issue too. Also the rear brakes don't slow it down because this issue. I have no idea what the problem could be.

Thanks