Most board track tanks are fairly simple. Some of the early ones were basically riveted boxes, others nicely contoured and soldered. Many early tanks contained a separate oil tank within them - some with oil on one side and fuel on the other. The Cyclone was simple in appearance but does have several unique curves. I mocked this up in hard cardboard(not corrugated) and a glue gun. Plenty of gussets keep it from flexing - important when trying to take measurements or fit a piece over a weird angle. In the end what this does is allow you to see the shape in 3D. Once the shape is acceptable, you can make templates by laying paper over the tank, adding creases, etc. to conform to the curves. Once unfolded, these templates allow you to see the shape needed in steel. The folds will show where shrinking and/or cuts should be made. This is just basic pattern making. You can also use the "buck" you just made to trial fit some of the new pieces although a buck is typically hardwood and would be used to form the metal. All in all, this tank won't require lots of shrinking or forming. A little rolling of a few parts is all that will be needed. These tanks were primarily long and skinny. Adding a baffle or two in there will help prevent sloshing fuel from upsetting the bike. Baffles would also limit cavitation at the stopcock when a low fuel level shifts around. Baffles could also limit flow a bit in a rupture situation(God forbid). It's unlikely that I would ever fill the tank completely but remember, 2 1/2 gallons of fuel is about 20lbs and if you have ridden lightweight motorcycles you know that a full tank can be felt by the rider. It's good practice to build it properly rather than doing just what's needed to get by. JMO I have also revisited the seat idea. The Mesinger "Motorcycle Racer" is the quintessential board tracker seat and maybe the most attractive but I am finding more and more examples that didn't use it. The picture below is of the Michaelson racing team(c. 1912-1914). These bikes are all wearing what looks like compound sprung saddles. I don't know the production years of the "Racer" seat so perhaps it wasn't even available at the time. Certainly it wasn't the only option. Brooks, in fact, made saddles, bags, and even rifle clips for motorcycles at times issueing separate catalogues for bicycles and motorcycles. They even list saddle models made for "speed work". If you are interested, go to http://www.brookssaddles.com/brooksengland.html These are pdf versions of most of Brooks old catalogues! Check out some of the options. Really cool stuff. The Mesinger isn't absolutely necessary and, based on these findings, I might feel justified to venture into another easier option. The proper look is still imperative so no everyday Schwinn seat will do.
Mounted the engine. A neighbor came over and we started it with the engine in the frame last weekend. It ran well. Still have to configure the jackshaft and Comet 40 series convertor. I'm a little disappointed that the motor is so wide but unless I scrap the twin idea, radically shift the motor, or put a smaller go cart clutch on there I will have to live with it. A buddy reminded me that it isn't really a close replica other than the overall shape/concept and he's right. It's the challenge of making it all work together with the Cyclone primarily as an inspiration. There are many things I would change already if trying to make it more accurate. I battled the idea of scrapping the frame and making a new more accurate one with better proportions to the 26" wheels but, come on, I would never finish it. I'll save those lessons for the next one! I did a little smoothing of the main tube intersections and added the spring perch/rear brake bellcrank mount to the bottom bracket/seat tube. This will act as more of a gusset than anything else. I've seen this perch on all Cyclone street bikes and BTRs and the only one that is without the perch is the Cyclone BTR that recently sold for over $500,000! I found the article that mentioned it's provenance and that, although very original, the rear end had been rebuilt at some point. The lack of the rear spring perch on this popularly photographed BTR had confused me until that explanation - it was unused so simply left off the rebuilt rear triangle. The seat was formed by bending plywood(original Mesenger seats had plywood bases) using the kerfing method. It isn't complete by any means as I will shape it before padding and covering it. I just wanted to see if it added to the lines of the bike. I have yet to see a bicycle seat that looked right and Mesenger repros are $500. I might spend that if building a full sized 28" wheel frame but don't want to drift from the DIY feel of the project....