If you are not a gear head , trust me this is crazy .
https://thekneeslider.com/bugatti-t7...icycle-engine/

At 10,000rpm, I guess some interesting reduction gearing? I know I cannot pedal that fast.

Pretty neat.

Does the drive chain also drive the camshafts, the super charger or both? How they fit all of that mechanical assembly in so small a package is remarkable.

Yes, it looks like one chain for the engine mechanicals and one to drive the rear wheel. Both chainwheels appear to be the same size.

Since the crankshaft is North-South, it looks like the small sprocket closest to the front wheel is the output from the engine. The pulley between the output sprocket and the chainwheel appears to be for tensioning the chain. It looks like there is a slot in the side cover to move the pulley up or down.

What is that brass wheel at the front of the engine? Notice that it is mounted to a plate.

10.5cc, overhead valves and 10,000 rpms, and 4 stroke. This is like the predecessor to Honda's racing motorcycle and first Grand Prix engine. Perhaps Soichiro Honda would be fan of this engine/bike.

I've would also like to note that Ettore could have created horsepower by just making the engine displacement larger. But he chose this path. Interesting. Was this the prototype for later automobile engines?

This reminds me of the I believe early working predecessor to the Honda CBX, a 125cc six cylinder 4 stroke reported to have been run on the dyno at 25,000 RPM for 24 hrs.

It convinced the exec's and they greenlit the project and as stated above the rest is history.

Also segue's a bit to the earlier first? Kawasaki KZ 900 in the states that was run literally WFO for 24 hrs at Daytona, wore out several riders, chains and tires logging 2631 mi. with an average speed of 109.64.

It supposedly ran out of fuel at one point but was carrying enough speed to get back to the pit to refuel instead of botching the test.

There were no other failures.

And Yvon DuHamel rode a Yoshimura tuned one to a one lap record of 160.288.

https://en.wikipedia.org/wiki/Kawasaki_Z1

You said gear head and desmodromic pops into my brain, lol.
But I'm not a racing nut, no.

In denial much?

Very interesting stuff.



A little more about the engine
Ettore Bugatti's cyclemotor

The bitter truth is I am addicted to motorcycle racing
I subscribe to MotoAmerica, MotoGP, World Superbike, BSB, IOMTT and any other TT I can find.
I got up at 2am this morning to watch Isle of Man... Love watching McGuiness ride

Learned of this years ago referencing the race plane that was at the EAA museum in Oskosh.

Wild on both.

tragedy for the airplane recreation.

always wondered if the cyclomotor displacement and or output was tied to moped regulations in France.

Looks like the quickest way to turn your lower legs into hamburger meat, if you happen to crash that thing......
But it does look like a nice mechanical conversation piece.

Is it odd he didn't make it to fit a Bugatti bike? Ettore's bike frame had four small-diameter downtubes (and 4 toptubes and 4 seat tubes for good measure), so the engine mount would have to be quite different.

Here's one reputed to be an original:


Crazed lunatic, er ah I mean gifted genius framebuilder Art Stump made a reproduction, or was it two? I forget, but here's a pic of one of Art's creations.

Made in the late '70s IIRC.

Mark B

Art made at least two, maybe three.
one received damage at the derailleur hanger.

his typical fixture was quite minimal, the jigs to hold the quartet of tubes was much work in of itself. My guess was multiple bikes to rationalize the set up effort.

Enjoying this thread. Thanks for posting.

Three+ decades ago, my fellow boss had his type 35A parked in front of my desk. The real deal. Among his many rare and eclectic collection, he did take this one and participated in the modern era Mille Millia historic event. Always a treat to see such and even though some of it, for its era lacked. Recall he told me the 35A was considered the 'boy racer' model.

Then a few years later, by accident was curious of a rambshackle appearance building, though did see enough outside that it was something to do with old cars. Gate was open one day and made a visit. Four different Bugatti in various state of condition.
(ps. Don't ask or pm requesting location.)

Its a bikey forum, so carry on with that. bye

Inspiration for the "birdcage" Maserati?

Anyway, I'd imagine everything would have to be braze-on; eh, anyone that could build that frame could probably fabricate custom clamps.

Wind tunnel testing of that might prove interesting.

Is that contraption used by Ryder Hesjedal in the 2012 Giro?