The front sprocket is a 17 tooth. You will want to install a 36 tooth on the rear. You can order a custom sprocket from PBI Sprockets as you will not find a 36 tooth already made. You can order from here.
https://shop.pbisprockets.com/product.sc?productId=503
Here's the information you will need to enter.
428 sprocket, Center Hole Size. size: 64mm, 58mm if you remove the spacer ring - Size of bolt holes diameter. 10.5 circle diameter through center of all bolt holes: 96mm
Important Note: Sprocket will need to be milled to recess and install the stock steel spacer ring.
Here's a video on changing the sprocket.