1974 Harley-Davidson RR 391 Back to contest Vote Description 1974 Harley-Davidson RR 391 Only three of these 391's were produced, and this is the only one still in existence. It competed in the 500cc class, benefiting from the light weight and agility of a punched-out 350. Leave a Reply Cancel replyYour email address will not be published. Required fields are marked *Comment * Name * Email * Website Δ Share OK More