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Continental Racer: Sinroja’s Royal Enfield Drag Bike

Royal Enfield Continental GT drag bike by Sinroja
A couple of years ago, Sinroja Motorcycles were one of the first workshops to join Royal Enfield’s new custom program. They built a couple of bikes, and the relationship went well. So when Sinroja were looking for a brand partner for their latest project, they knew just who to call.

The Leicester-based custom shop wanted to enter the European Sultans of Sprint race series in the ‘Factory’ class. All they needed a factory to collaborate with.

Royal Enfield Continental GT drag bike by Sinroja
Royal Enfield and their Industrial Design boss Adrian Sellers came to the party with a brand new Continental GT 650, but there was an unexpected twist. By the time everything was singed off, Sinroja had just four weeks to prep the bike.

“Usually we can do aesthetics or performance in that time,” brothers Rahul and Birju Sinroja tell us, “but this project needed both. It had to look good and go fast.”

Royal Enfield Continental GT drag bike by Sinroja
It certainly needed to be fast. Sinroja’s Continental would be competing with a nitrous-powered BMW 1250, a nitrous-powered Indian Scout ridden by the legendary Randy Mamola, and a supercharged 200-plus hp Harley.

The brothers already had a concept in mind: they would loosely take inspiration from a drag racer Royal Enfield themselves had previously built, ‘The Lock Stock.’

Royal Enfield Continental GT drag bike by Sinroja
With help from Tamas Jakus at Jakusa Design, they quickly mocked up the design and graphics for ‘Two Smoking Barrels.’

But sharp looks alone weren’t going to cut it. With just 47 hp from its 648 cc parallel twin motor, the Continental GT 650 was seriously outgunned. “The project direction was clear from beginning,” the guys tell us. “We knew we had to go as lightweight and as powerful as we could.”

Royal Enfield Continental GT drag bike by Sinroja
“When the already naked Continental GT (which weighs 205 kg) was delivered, we were worried. There weren’t any big body panels to strip to lose weight quickly.”

Luckily for Sinroja, performance experts S&S Cycle were in on the project from the word go. They’d previously worked with Royal Enfield and Harris Performance on ‘The Lock Stock,’ and filled the brothers in on exactly what sort of numbers were achievable. That info also helped Sinroja set a competitive target weight for the Continental GT—150 kilos.

Royal Enfield Continental GT drag bike by Sinroja
S&S Cycle sent over custom pistons and sleeves to bore the twin out to 750 cc. They also supplied new injectors, cams, and an ECU, and built a straight-through twin exhaust system.

That gave Sinroja a great naturally-aspirated base to work from, but they still needed an extra boost. So they called on Trevor Langfield at Wizard of NOS to help them set up a unique dry nitrous system. The system’s neatly packaged underneath the seat, where the GT’s air box and wiring used to be.

Royal Enfield Continental GT drag bike by Sinroja
With performance sorted, Sinroja started plotting the Continental GT’s diet. Everything was stripped off the bike and weighed, so that they’d know what to keep and what to ditch.

They needed a tight front end, so they dug a modern sportbike front end out of their parts bin, shaving off one of the brakes to keep things light. Danny at Fastec machined up a set of billet aluminum yokes to work with the stock headset. The lighter forks and yokes accounted for almost 10 kg of weight saving.

Royal Enfield Continental GT drag bike by Sinroja
The rear end received a more radical treatment. Sinroja ditched the rear suspension entirely, then fabricated a new hardtail from Reynolds tubing to save weight and extend the wheelbase. They wanted to swap out the wheels as well, but couldn’t get a set of 17-inchers made up in time. So they kept the stock 18-inchers, wrapping them in Continental rubber.

Weight saving became an obsession. Rahul even recalled a lesson from university, where his professor explained how Toyota shaved 10 kg off a sports car just by reducing the weight of all the fasteners. So Sinroja swapped every last nut and bolt for lighter versions, and trimmed another 2 kilos off.

Royal Enfield Continental GT drag bike by Sinroja
With the rolling chassis done, it was time to piece everything together. Chris Walton helped the brothers out by shaping an aluminum dummy tank, the tail end of which actually forms the seat pan.

Three fasteners hold down the entire arrangement. Underneath it, you’ll find a two-liter fuel reservoir, a Lithium-ion battery from Antigravity, and most of the electronics. (Towza from Towzatronics built a custom wiring loom at the last minute, trimming a further three kilos from the bike.)

Royal Enfield Continental GT drag bike by Sinroja
The last few mods included a super-minimal cockpit, and a carbon fiber front fender made from the same mold as the one found on ‘The Lock Stock.’ Glenn at GD Design handled the paint, showing off the English flag on one side, and the Indian flag on the other.

Then Ian Tam, Constantinos Panayides and Tommy Butterworth helped Sinroja setup and tune the bike, along with Royal Enfield’s tech center staff.

Royal Enfield Continental GT drag bike by Sinroja
On its first outing, ‘Two Smoking Barrels’ took gold at the Punks Peak hill climb at Wheels and Waves. And it came fourth at the last Sultans of Sprint race, narrowly missing the podium.

Not too shabby for a last minute rush-job.

Sinroja Motorcycles | Facebook | Instagram | Royal Enfield product page | Images by, and with thanks to, Marc Holstein

Sinroja would like to thank Royal Enfield, along with sponsors S&S Cycles, Bell Powersports, and Contimoto UK.

Royal Enfield Continental GT drag bike by Sinroja

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