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Looks like a Honda 550k1 drum&wheel to me Mick
500 wheel, the rear sprocket has 34 teeth and the 550 had 37 IIRC. Also the rear brake plate looks to be a 500, they changed design for the 550 and to my eye that still looks to be the old style plate.BTW the sprocket cover dish seem to have been adapted or changed, it should be all in one piece and completely cover the bearing retainer, that's looks to be off another bike or has been chopped for some reason.If you ever remove the sprocket mount there is a difference in the damping rubbers between the 550 and the later 550s, the 500 were in 2 parts and the later 550s IIRC went to a one piece design.