V Twin Royal Enfield Bulldog

In collaboration with Fuel Magazine I recently interviewed Guy Brown, founding member of Carberry Motorcycles. Carberry was a Melbourne based company that developed a double barrell engine using Royal Enfields 500cc single as a base. This bike which Guy affectionately calls the Bulldog, is one of only a handful of the Carberry Motorcycle in existence and this is the story behind the Carberry business and how they took Enfield low powered thumper and turned it into a twin cylinder beast.

Carberry Motorcycles was the brainchild of Paul Carberry who, along with Guy and engineer Ian Drysdale, produced 11 Enfield “Double Barrel” V-twins. The idea behind the Carberry was to build an Enfield that was suitable for typical Australian riding conditions. The Enfield design had remained frozen in time since India took over their production back in the fifties; from the mudguards through to the pistons they didn’t change a thing for almost 50 years. While this was fine for Indian riding conditions, in other countries where prolonged, higher speeds are demanded, engine component failure was a reoccurring issue. The Carberry was designed to be a reliable and affordable revision of Enfields original design.

Guy’s Carberry, started out as a stock 500cc Royal Enfield that he had acquired during the development of the company. Two 500cc Enfield heads, each bored to 535cc were mounted on the sand-cast, Carberry bottom end at 55 degrees to form the V-twin. High compression Accralite pistons and aluminum barrels were added to avoid any of the old high speed problems and a new cam, 5 speed gearbox, Nissan hydraulic lifters and Daihatsu oil pumps completed the engine transformation. The resulting V-twin produces around 50bhp which is almost three times the power of the original motor and with the upgraded lubrication system, it has more than 90 times more oil flow than Enfield’s design.

To accommodate the Carberry V-twin the Enfield’s frame was extended by 60mm at the backbone. A twin down tube configuration was added to fit the crankcase and additional gussets provide extra strength. Finally minor adjustments to the tank and the seat were made and it was ready for the road.

“The Bulldogs power comes on at around 1000rpm and pulls hard right up to its 4500rpm limit.”


Through the twisty roads of the Yarra Valley, Guy says he’s played tag with many modern sports bikes and although it doesn’t have the straight line performance to match, it can easily hold it’s own. The V-twin will happily cruise at 140kmh and can even comfortably sit on full rpm thanks to the de-stressed design of the Carberry motor. Since it was completed Guy has done over 25,000kms on the Bulldog and it’s never skipped a beat.

For more photos of the Bulldog grab yourself a copy of issue 10 of Fuel Magazine.