Some links for you, Robert, as we discussed:
EBR Idler Sprocket for 520 chain
EBR Idler sprocket spacer
EBR chain drive front sprocket nut
EBR chain rub
PBI 277X 21 tooth front sprocket from Powersports Superstore
PMP rear sprocket -- any size you want -- 51 tooth is great
My website
My chain drive setup