Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/125877
alter which parts would drop about $10 per frame. Ho les Can be incorporated into the fra me while in the m old , holding a tolerance factor of +/-.005 in. This of course eliminates any lab o r directly related to the frame. It's a simple bolt on operation ." Marsee foresees easier production flow with his m agnesium /all oy Magnum. " Ano th er beau ty o f the mon ocoque cast is simplification of the n ormal sub-assembly steps. For example, fro nt end assembly can be done in one are a , rear end assembly in ano ther area and power supply assembly in yet ano the r area . The f inal a ssembly can b e accomplished w ith ease , because it is not assembled a piece at a time but b y sections at a time. This would eliminate the typical production b ottle neck where the workes wait their turn to moun t apart." The Magnum's designer admits that his prototype is one of co mp ro mise because of monetary problems and the fact that he built a multi-purpose frame, one that could be used for cowtrailing, motocross, street and flat tracking. He also ad mits to having built it "heavy" so it could accept an engi ne from 125 to 4 00cc di me nsions. Presently , the Magn um is equip ped with a 125 cc Sac hs "B" engine and the overall weight of the prototype is 190 . Utilized in the package are Kawasaki F·II wheels and brakes , Ceriani medium weigh t fo rks and Arnaco shocks. Marsee asked that we consider the design on its potential rather than its performance as delivered by the prototype. Mentioned in pre-testing comments were the heavy front end , the forks that had too little travel for MX applications and the "too far forward" mounting of the engine. All warnings proved to be spot-on. The front end was indeed too heavy, although the incorrect front /rear weight distribution was probably caused by the long swingarm rather than faulty frame design. The forks (5" travel road units) were short on travel; and the fear end, which hopped like a rabbit in heat, rode on a pair of completely wasted shocks no dampening action at all. Those actions negated any field analysis of the Magn um's handling potential . The project has consumed $6,000 of Marsee's limited funds, not to mention an estimated 3,000 hours. He has documented all designs and patents have been applied for. Mentioned many times d uring our discussion of the Magnum were the interest and efforts of Dr. Hardy Taylor and Charles Womack of Georgia Tech's Industrial Division, both of who aided Marsee with the Magn um. The Burrellco Company in Kenesaw , Georgia performed the actual frame fabrication and machine work . Georgia Tech 's assistance with the Magnum laste d three months, during which period they tried to raise money for the bike for street use. Marsee and John Penton discussed it and decided th at if they could be marketed for $1,000 retail, they could sell all they could make. Their discussions centered around the use of a Sachs 125cc engine in a " sort of' cafe bike. According to 'Marsee , "It was a neat idea, but Sachs engines would have cost us $400 each . , So · no way." Other engines were located , a Canadian Kohler and a Sachs Wankel, but they required the use of a torque converter since a suitable gearbox was unavailable . Marsee and Georgia Tech decided against that approach due to the excess expense of R&D. So where to now ? "A major motorcycle manufacturer here in the U.S. is presently looking at my project. I'd like to see them place it in production as it would be the reality of a dream if it happens," states Marsee . The Magnum 'is more than a dream. It's a reality. Sure the prototype is rough. Sure, it doesn't han dle with the prese n tly mounted front and rear I suspension c o m p on en ts. But look closely a l it. You might be riding so mething very sim ilar to it in the near 1 future. • • • IIG lIB IIG .... g =- g -e- r--- O'l ~ r--- ...... .... (,) ...0 E .... 0(,) (,) 00 The fuel line comes from the under-the-seat gas tank. Above the carb is a boss in the casting: a potential spot for an air cleaner box in the 'top tube'. Lookit the head on that! Massive appearing; it's hollow. / > ED--R e" Marsee is interest ed in any and all reader resp ons e to h is project. Int erested parties may co n tac t him b y writ ing 2 510 Rolling View Drive, Smyrna, Georgia 30080 or by ph oning 404 /436-2713 . I i iI , J 27 -