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/125822
<, M .... '" ~ N ~ < ~ W Z W ..J U >- U Custom airfil1llr feeds baby Tillotson pumper through a flex-hose. The Sachs-BMW-Wankel: Pauli's Roto-Rider 6y John Ulrich . Photos by Art Friedman & Ulrich An American assembled Wankel Sachs/BMW is here, but don't rush right out, sell your Yamaha, and line up at your local Pauli dealer. The backyard engineer/builder, DavePauli, has not as of this .date been offered a posi tion in the BMW R&D Department, but when he tools down the street, he doesn't see a carbon copy of his bike at every intersection. How the "Roto Wonder" idea first came to be implanted in the creater's subconscious, to one day leap in to his consciousness, is unclear. But after investing about SI80 in his BMW R-69 he has something very differen t from the run of the mill boulevard blaster. The bike is undeniably 1) unique, 2) innovative, 3) customized to fit the owner's own personal taste, 4) home built, and 5) unrmished. You see, certain minor "details remain to be worked out, such as the elimination of vibration so bad it makes your bones hurt. Dave is confident that a complete balancing job will cure the problem,. which would not have ever occurred if the stock Sachs balancer had fit in the unmodified '69 BMW frame. Riding the Roto is an educational experience of the once-in-a:lifetime category. Yeah, boy, it sure is different from the Honda 500 you ride to work every morning. First you kind of step on the starter pedal quickly, and the de ep.throated lawnmower sounding one-rotor burbles to life. Then you almost amputate your leg on the license plate bracket, snick it into gear, and motor off onto the highway. The first thing you notice is that you can almost see the speedometer if you're seĀ·ven feet tall, and that the handlebars do not afford enough leverage for maintaining control easily. But then, that's not too uncommon on customs. Handling is unusually mishandled... the BMW frame geometry was designed with a certain engine weight distribution, and the Sachs Wankel just doesn't have the same weight, much less in the same places, as the BMW motor did. Wobble around a tum, gas it in the middle, and the typical BMW torque reaction rears its twisty head. The whole handling situation reminds us that we don't especially like customs. It is all a matter of taste...some people don't like Electra Glides, either. One nice thing, though; the stock BMW brakes were retained, and work well enough. Additionally,' the bike incorporates such startling safety innovations as areas of luminosity on the front forks and rear fender. Knowing that you can stop, and maybe even be seen by the 87 year old senile Saab driver abou t to make a lef in your path, you wick it up a little, and hit second, then third. Somehow, it feels a little funny when you shu t off for the shift. Pondering this, you roll off the throttle, and Holy Cement Mixer! It's gonna blow up! What am I gonna tell Dave? Oh, no, I don't want to have to buy this stupid thing! I hope the shrapnel doesn't kill me! Maybe I better bail ou t! Then, as quic k1y as a famous California earthquake, it has come and gone. It really needs the balance job. for sure! With a set of what we like to think of as "proper" bars, a rubber mounted, or balanced, engine, a conventional seat, and heavier fork oil, the Roto Wonder might be a machine every mother would love. Even as it is, Dave's bike is the most significantly different home brew we've ever seen. . . The stark simplicity of ~ BMW R69 frame really shows on the Rota. The Wankel is a little narrower than a stoc:k BMW.