OEM size of R1's on 4410?

[wango tango]

my local dealer is having a hard time finding the size wheels/tires i'd need. i want to switch from my R4's to R1's on my 03 4410.

anyone have any info? anyone have any wheels/tires for sale?

 

[beenthere]

Does switching mean going to the two piece rim and disk for R1's?
Part 6 and 7 in the attached pic that shows the two styles.