Looks like a 16' comparing the size to the adjacent vehicle.
(http://i957.photobucket.com/albums/ae59/CheneySachs/HP_zpsf5026e1c.jpg)
(http://i957.photobucket.com/albums/ae59/CheneySachs/15496859-16590-large1_zps54b56102.jpg)
Dale Fisher
Penton Owners Group - Memberships
Mudlark Registry
Facebook - Cheney Twinshock Racing Group - Administrator
'70 Six-Day 125 - V2017
'71 Six-Day 125 (Dave Fisher's) - V5553
'72 Mudlark - W257
'73 Jackpiner - 175 21159727
'74 Berkshire 100 - 40171056
And some silly other bikes...