There was an auction last week-end in Mich and these two bikes were offered. The 1970 yellow "Dunstall" and the 1975 blue "drag" bike.Owner thought the yellow may have been an early prototype,no or removed serial # on cases and unknown internals.Some trick bits. Blue 75 had stock pistons he thought with headwork +.Both were def. old school. Did not go as he said he was going to protect them. The bidding went,according to him to $4750.00 for yellow and around $1800.00 for the 75 blue.Neither one has been ridden in a "long" time. He still has them. DEAL or NO DEAL ,what would you have done sell or keep. Sorry these are the only pics I have from his add.