Honda XR600 9 Cylinder Radial Engine

Honda XR600 based radial engine

There's a certain mystique associated with radial engines which may be why several builders have recently built motorcycles wrapped around the circular powerplants. Of course, they look pretty cool, too. As we've also pointed out here before, several motorcycle engines have been adapted for use in airplanes, usually in their standard configuration but using an adapter of some sort for the prop. This XR600 radial engine project blurs the line by building a 9 cylinder aircraft radial engine out of the cylinders from a Honda XR600 single.

Details of this project are limited but it seems Russell Sutton, a New Zealander living in Australia, is building this 8 liter engine which will have a redline around 4000 rpm and a planetary gearbox, made from gears out of a Caterpillar transmission, which will reduce the prop speed to 2500 rpm. The engine will eventually find its way into an airboat.

These photos originate from Ian Drysdale, who's been known to mix engine parts in some interesting combinations of his own.

Some of you Aussies and Kiwis build the coolest stuff!

More photos below:

Honda XR600 based radial engine

Honda XR600 based radial engine

Honda XR600 based radial engine

Links: Eurospares (bottom of the page) via Honda Trail Bike Forum
Related: Jesse James   JRL Cycles   Gatsby


  1. Gladys says

    Being on the other, flip-side of the world, all the blood goes to their brain…better for creativity and engineering.

  2. Murph says

    8 litre engine..Where does the extra 2.6 litres come from if it has 9 x 600cc cylinders?

  3. willie schmitz says

    Kudos to Mr. Sutton! Hopefully we’ll see a follow up on the finished product.

  4. says

    That’s cool. What about using Harley jugs with push-rod valve train for simplicity? Ya, I know…armchair quarterback!

    p.s. Check out Verner, HCI or Rotec if u like the round sound.


  5. russell sutton says

    Not too computer literate, but here goes. Did you notice the new sleeves protrude into the case? Stroked to 120mm (original 80), to achieve 2:1 rod – stroke ratio, torque oriented. Pistons ex GM comodore V6, 9:1 compression ratio!!
    Yeah the Yamaha pots on 1950cc V twin with rods would be sweet as!

  6. says

    VEERRRY Nice! For the valves PLEASE PLEASE use a Bevel!!! A rotary, bevel, desmodromic system would make me shiver!!!

    Please, somebody make the Roto-Bev-Desmo!!!!!!!!!!!!!!!!!!!!!!!!!!!!!