Jesse James and JRL Cycles built customs based around the Rotec 7 cylinder radial engine, now Paul Yang of IronGatsby Motorcycle has produced the Gatsby. I ran across this bike in the latest issue of Barnett's Magazine and according to the article, Yang has been working on this for 2 years so it sounds like these radial engine ideas popped up on the radar of some builders in a relatively short period of time.
The bike has 23 inch wheels on both ends and a CVT (continuously variable transmission). Looking through the photos in the magazine, it's difficult to figure out exactly how the exhaust is routed and the CVT setup is hidden pretty well, too.
Given the size and shape of the radial engine, it's a challenge to build a motorcycle around it, making it look halfway decent in the process is definitely a lot harder. Is this in any way a practical ride? Obviously not, but in the same way as the Jesse James creation and the JRL Cycles customs have shown, you can power a motorcycle with almost anything given a decent amount of time and fabrication skills. Interesting.
Link: IronGatsby Motorcycles
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Wow , nice job . That is one sharp looking custom .
And the rear tyre’s profile is…
120/70X23 on both ends
I’ve always wondered, especially for this layout, how much gyroscopic stabilization the engine provides, and how much that inhibits turning. At least this one has a fairly narrow (comparatively) rear tire.
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I looked at his site, although unique styling which I give him credit for I find his customs kinda ugly.
As for gyro affect I’m sure it is substantial but at least it will not toss you on the ground when you pin it like this one :>)
http://thekneeslider.com/archives/2006/05/10/radial-engine-powered-motorcycle/
WHAT rotating mass/gyroscopic effect?
http://www.rotecradialengines.com/photos/parts1.htm
Considering that peak power comes at 3700 rpm, how hard is it going to rev, anyway?
Is there really more rotating mass than your typical 4 cylinder?
The same rotating mass/gyroscopic effect that keeps your motorcycle shiny side up.
WWI rotary engines had significant gyroscopic effect because the crankshaft was stationary and the whole engine mass rotated around the crank. These modern radial engines don’t rotate and require low mass crank and flywheel assemblies due to the uniform distribution of reciprocating elements around the crank’s 360 degrees of rotation. Hence, negligible gyroscopic effect.
It’ interesting to note that these Radial-engined customs are only photographed from the power-output side of the engine. The other side has oil pump, distributors, carbies, starter motors and all the other ugly bits…
“WWI rotary engines had significant gyroscopic effect because the crankshaft was stationary and the whole engine mass rotated around the crank.”
I’ve half joking suggested that somebody should make a bike based on a rotary engine. I think somebody makes a replica for kitplanes, so might be doable.
I’ve seen Mazda rotary powered bikes before, but this would take the cake!
Jesse James version I think will promote even coolin of each cylinder. However this longitudinally positioned engine may have a problem with heat, no.
I believe radial engines are very pleasing to look at but are very hard to be made to look good in a motorcycle. Hovewer the best looking radial engined bike I`ve seen so far is the french Verdel from 1912. Link: http://www.cybermotorcycle.com/gallery/classics_p/Verdel_1912_Radial.htm
Another idea could be a kind of cyclemaster version with the radial in the center of the wheel?