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In case you're sick of your main ride.......


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Now this is ingenuity....See attachment.

Wonder how they cool it?


I take a guess, they cool it with oil & air! grin.gif

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Aparently there is some confusion among the custom bike builders regarding the correct orientation of the radial engine.


Here's Jesse James' version using that same motor.



And regarding the cooling. The Rotech R2800 makes only ~110HP and that from 2800cc. There's huge surface area of cooling fins in that motor to keep it cool in both configurations.




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The Rotech R2800 makes only ~110HP and that from 2800cc

Yeah, but thats 110 HP at around 2500 RPM's! Which is close to redline for THAT engine.

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That’s kind of ironic. The first V-twins were two cylinders from a radial engine design. So now they someone has made a complete radial engine in miniature to put in a bike.

Talk up about coming full circle


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thats what I thought ..... how much heat this thing produce? I would hate to sit at a red light with that thing, but i think it looks way cool.

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Hmmmm, my guess would be that heat is related to the power output and not (just) the number of cylinders.
I don't see that is quite so. I believe you'll find the heat issue is related to the displacement rather than the number of cylinders.


Heat is the result of fuel burn, and also effected by exhaust effeciency. So, just like fuel mileage, it's related to displacement, and to effeciency.


The big motor operates at low throttle, and thus low cylinder (combustion) pressure. That's why it's inefficient - which also produces the poor exhaust flow. And, therefore it uses lots of fuel to produce the power needed to move it.


Another way to look at it is there are huge friction losses moving all those big parts. It might take 80 hp to run that engine perhaps at 1500rpm. That means it produces 130hp to run the bike at 60mph. A smaller engine, optimized for effeciency at the 50 net hp needed at 60mph might only require 30hp to run it. Thus 130hp vs 80hp. There's 50hp extra heat being generated - in order to operate the larger engine components.


Best wishes.

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