(April 24, 2023) WALWORTH, Wis. — This Sept. 6-9, Mecum Auctions will offer the renowned John Parham Estate Collection at the National Motorcycle Museum in Anamosa, Iowa, an assemblage that includes more than 300 collector-grade, museum-worthy motorcycles and upwards of 1,000 lots of Road Art encompassing more than 6,000 pieces in total.