My chain is going to rub on the tire just a hair and it will align better if I space the engine sprocket not the wheel sprocket. What is a good technique for spacing? Any special tools needed (i.e. gear puller etc...). What material should I use for spacer..metal, nylon etc..? It appears to be an appropriate fix because the installation guide says quote, "Sprocket on 66cc my need spaced outward to clear 415 chain", end quote.