Take a look at both pictures, appears to have frame on both side of the tank. So that would mean a narrow tank with double tube frame............Curt
Yes Curt that's clearly shown in both photos to be a "duplex", double tube frame & Pat's also correct about the HD fork and scissor damper. The Anzani motor is really trick for it's day with the single overhead cam/valve design. If I remember correctly it's a two valve per cylinder design. Check out the mag is located and driven by & mounted remotely off the gear reduction drive jack shaft (behind the seat tube). I don't recall seeing this mag drive setup on any other bike and I'm intrigued to see the timing drive mechanism required.
I'm guessing about the oil pump being located, it appears on top the crank case and between the two cylinders. better visible in the first photo and oil tank located above the single speed transmission. I've got eye strain from searching the exact spark plug location, but just can't see them. same with carb or carbs (which would be cool) a couple of things lead me to believe there are dual carbs, but perhaps I just want them to be there. I'll research it later. Note the spring saddle on the single seat tube between the double frame tubes.
Temple loaded his bike frame with personal innovation and this Anzani engine is really radical for 1923. Thanks FOG and Curt for the photos I love this old iron! I've seen the second photo, but never stopped to really understand what I was looking at.
I'll not be offended if any that know the truth on what I've speculated about come forward with the necessary answers.
Dual carbs would be cool though! The long air cleaner and the apparent redundancy of fittings below and , less clear, above the intake area are visual clues that make me hope this is the case.
Rick C.