Air filter with an inlet of 54mm suitable for pre-65 trials and many Japanese applications as follows:-
Honda CB550SC, CB750K/F, CB900 -82, CB1000, CB1100F, CBX1050
Kawasaki GPz 750/900, Z750LTD, Z1000/1100/1300 81-82
Suzuki GS650 to GS1150 80-85 icluding GSX/Katana
Yamaha XJ550-900, FJ600/1100, XS1100 80-81, FJ1200 93
The filter is approximately 75mm at it's widest point tapering down to approximately 50mm. The overall length is 80mm from back to front. The end caps of the filter have a nice deep chrome finish.
These filters should always be oiled before use for maximum filtration efficiency. K&N Filter Oil is available from this site