Ok, so I ran into a new situation tonight. I was trying to place a 54 tooth rear #35 sprocket on my kart tonight. I found that I am unable to use the 54 because of the inner lip on my plastic sprocket guard. This lip lifts the chain off the teeth. In other words the bolt holes and the teeth of the sprocket are too close together for the inner lip of the sprocket guard to fit between without lifting the chain. Anyone else ran into this? I have never used anything besides the same plastic guard that my local track sells. Are other sprocket guards better designed to have clearance for smaller sprockets? I don’t run into this problem when I run a 55. Thanks for any help and I hope I was clear and not confusing. 
http://www.accelerationkarting.com/rocketsprocketchainguide.html
We use these on our fleets and are designed for smaller sprockets if you choose the smaller size