BMI Karts lets you have the choice of selecting the sprocket ranging from a 53 to a 75 tooth sprocket. The product description didn't provide the outside diameters for each different tooth sprocket. So I went online to look for a chart that displays the outside diameter for a #35 chain size sprocket for different numbers of teeth. I found this chart online from Azusa Engineering regarding sprocket diameters of #35 chain size sprockets at http://www.azusaeng.com/Sprockets/AzSDno35.pdf.
I also found another website that provided the same information at http://ablproducts.com/35-chain-sprocket.html. So a 53 tooth sprocket would be about 6.5" in diameter and the 75 tooth sprocket would give about a 9.17" diameter. So I can pick a sprocket in between these measurements. So If I decide to go with a 65 tooth sprocket, I'll have a sprocket with a diameter of about 8" (7.978"). I can use this number to help me in determining the speed of the Boca Dune Racer.
The 36V 1000W motor has rated speed of 3000rpm. The sprocket on the shaft of the motor is a 11 tooth 8mm 05T sprocket. I am not sure what the 05T means but I found the diameter of this sprocket at this website https://electricscooterparts.com/sprockets8mmchain.html. They list the OD of this sprocket as 1-1/4".