New V-twin will have 3500cc and six-inch pistons

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US firm Bad Dog Cycles is working on a monstrous 3.5l bike engine featuring six inch-wide pistons.

Owner Bill Price says: “I’m not too happy with the first version of the frame and will be making some improvements there. Our focus is going to be on the power unit itself for a while yet.

“The motor has several modern features which while they’re not revolutionary, nobody had brought them together yet in a large v-twin. 

“We will incorporate down-draft intake ports, small included valve angles, DOHC, four valves per cylinder and three plugs per head to maximize power and attain excellent breathing. 

“The bottom end features a one-piece billet crank with bolt-on counterweights, side-by-side rods and plain bearings for mains and conrods.  Ignition and fuel injection will be controlled by an engine mangagement unit like the Motec M400.

“When I was starting this motor project I wanted to find a niche that wasn’t too crowded with other motor designs. 

“So many people have done excellent work with water-cooled twins and fours, harley-style pushrod twins and air-cooled vertical twins.  Making the big-bore design work reliably is also an interesting challenge and sure to keep me busy!”

Guy Procter

By Guy Procter