In the flesh, or, at least, alive online, the venerable “Half a VW” motor.
Airplane Motors Forever
I like all the design functions, I just thought, for a stripped street racer — I have some experience — something besides the stock carbs would be an improvement. But think: the motor, the frame, all stripped? It￼’s lighter, more nimble, strictly speaking, the motor is pushing much less weight.
The functionality of the stock carbs might work fine, and the Bing carbs were CV, naturally able to adjust to elevation changes.
The first choice was Italian, Dellorto, I think that was the name. For the 750 (cc) motors? 36mm, or maybe 38mm, nothing larger, and I’m not sure that was really required, but with open mouths, and small trumpet-like mouthpiece, sure would be cool in appearance. The problem, in a strict urban setting? Dust is the enemy, and the air needs to be filters, keeping larger chunks of dirt out.
Last I heard, and this is dated data, but “Flat-slide Mikuni” was the hot set-up. I might suggest going back to the old round-top Bings, just for ease.
Then, too, most any outlaw VW/vintage BMW shop would carry parts for those carbs. While I wanted a rat bike like that, looking around, hundred-plus temperatures, distracted drivers? Less appealing. Then, too, I’m on the road a lot less these days.
That is a dream machine, but intellectually, I know I don’t need either a project machine, or an inherently unstable mode of transportation.
Stumbling around that original site, though, there were several older machines that had been updated. That’s all it is really about.
The older machinery, it always felt like it had a soul.
What would be more interesting, what I recall, the perfect size was the 750 cc flat-twin. Factory high-compression pistons, and maybe some kind of newer carburetor, event those Bing units. The reasoning, thusly? The 750 was balanced for the bore -X- stroke, and made for a smoother running motor.
I would guess an updated frame, like either of those RT frames, or even a mono-shock chassis, or adaption, that would be better. While to dual disk brakes look cool, and symmetrical, for raw stopping power, and less weight on the front axle? Go with a single disk in front, and the usual drum in the rear.
The model motor was the R75/5, and the frame would be “slash 7” for enhanced stability and improved handling, with front forks needing special attention, perhaps a total retrofit. Single disk brake in the front, as there is such a thing as too much stopping power, and the backend of the machine would be light.
Not quite an excursion with loud pipes and banging the corners, but still a pleasant enough trip down memory lane.