Return of the Cafe Racers - Sinroja Motorcycles GT 650 Drag Bike

Sinroja Motorcycles GT 650 Drag Bike

The Sinroja Brothers, Rahul, and Birju have just celebrated the 5 year anniversary of their workshop. Looking over their portfolio it’s hard to believe how much they’ve achieved in such a short time. Along with building an impressive collection of custom motorcycles for their customers, they’ve teamed up with brands and manufacturers on several special projects. Perhaps their proudest achievement has been the work they’ve done with Royal Enfield. 2019 was a particularly exciting year for the brothers. After completing a custom build for the launch of the new GT 650s, Rahul and Birju set their sights on participating in the Sultans of Sprint European race series. When Royal Enfield came to the party they pulled out all the stops to make sure their ‘Two Smoking Guns’ GT 650 drag bike would make a seriously big splash.

Royal Enfield Sprint Racer

Building a GT 650 Drag Bike

“The Sultans of Sprint family has always welcomed us as part of their ‘Circus’, but to be able to actually have a bike in it was almost a pipe dream,” says Rahul. “We were super excited when Royal Enfield agreed to build a bike with us but the timing wasn’t great.”

Due to unforeseen delays, Sinroja was left with only 4 weeks to complete their ‘Two Smoking Barrels’ GT 650 drag bike. To develop a visual concept for the project they enlisted the help of automotive designer Tamas Jakus at Jakus Design. Tamas sketched out a svelte, minimalistic vision for the GT 650. A bike devoid of any excess that had the perfect balance of form and function that the Sultans of Sprint demands. But just looking good wouldn’t be enough to win any races. Sinroja was set to compete against some seriously fast machines built by workshops who had been competing in the series for years. Thankfully they weren’t starting completely from scratch. Enfield had already built a GT 650 drag bike named the ‘Lock Stock‘ which gave Sinroja some good insights into how to achieve their goal; plus they had a few very accomplished partners on board to lend a hand.

In standard trim, the Continental GT 650 puts out around 47 bhp and weighs 205kg. Those are acceptable figures for cruising around town but not the sort of numbers you’d be bragging about at the track. Thankfully some old friends were ready to lend a hand. Royal Enfield’s performance partner S&S Cycles provided the brothers with some serious engine upgrades that boosted capacity up to 750cc. Sinroja then paired this with injectors and cams, a reprogrammed ECU and a free-flowing exhaust. It proved to be a great setup, but the brothers were still concerned they may be outgunned. So they went all out and installed a nitrous oxide kit with the help of Trevor Langford, aka the Wizard of NOS. Things were looking good, but there was still plenty of room for improvement, especially in the weight department.

The brothers set the bike a dietary goal of 150kg which meant the GT 650 would have to shed a whopping 55kg. To do this they stripped the Enfield down and began replacing the heavy standard equipment with lightweight, race-ready gear. The list of new items included an Antigravity battery, custom machined alloy yokes, one front disc instead of two and a lightweight modern sportbike front end. The frame itself also received some modifications that resulted in additional weight savings. The subframe was completely revised and a hardtail added which removed the need for a swingarm or any suspension components.

As for the bodywork, Sinroja replaced the fuel tank with a tiny 2-liter unit well suited for short sprints. Sinroja’s go-to alloy guy, Chris Walton, then hand-shaped an alloy tank cover and the brothers added a carbon fender to the front end. The most impressive weight gains achieved however came from rather unexpected places. After weighing almost every individual component of the bike Sinroja decided to replace all of the bolts with lighter alternatives and installed a minimized wiring loom by Towzatronics. It’s hard to believe but these 2 modifications saved a whopping 5kgs alone.

Royal Enfield Sultans of Sprint

Stiff competition at the Sprints

The Two Smoking Barrels GT 650 entered into the Sultans of Sprint series as part of the factory class. This class is for motorcycles powered by a 4 stroke air or water-cooled engine. There is no limit on capacity, but bikes are required to adhere to certain power to weight ratios. The factory class is open to all manufacturers who support the event which for 2019 included BMW, Yamaha, Harley Davidson, Indian Motorcycles and of course, Royal Enfield. Unfortunately, this meant that their GT 650 would be the smallest capacity motorcycle in the line-up. And after hearing what their competitors would be racing any notion of an easy win went out the window.

“We had super stiff competition this year like a supercharged Harley pushing almost 300HP, amazing nitrous powered India Appaloosa, flame-throwing BMW Spitfire and Phil aka “Rocketman” on a nitrous powered BMW 1250!”

Royal Enfield Sultans of Sprint

Sultans of Sprint Race Results

The 2019 Sultans of Sprint race series consists of 3 different race events around Europe. The first, at The Reunion in Monza, Italy was where the brothers hoped to iron out any kinks that were missed during the crazy 4-week build schedule. Unfortunately, heavy rain meant all racing was called off due to safety concerns. The second took place at the Cafe Racer Festival in Montlhery, France. Here Sinroja and their rider, Curtis Wright, finally had the chance to see what their GT 650 drag bike could do. Despite being the smallest motorcycle competing in its class the Enfield left a big impression. Along with pleasing the crowd with the most impressive burnouts, the bike narrowly missed out on a podium finish by mere inches, ending the round in a very respectable 4th place. According to their own recording equipment, the GT 650 achieved a 0-60mph time of around 4 seconds and hit the 100mph mark in only 7 seconds.

Before the 3rd Sultans of Sprint event, the brothers took their Enfield to Wheels and Waves in France where it once again outperformed expectations. Rahul and Birju entered the bike into the Punks Peak sprints, another well established, highly regarded event in the European custom scene. Taking part in the post ’75 class they were up against similarly tough competition. With Royal Enfield test rider Paul Young behind the bars, the GT 650 was pushed to its limits. Race after race it chewed up and spat out whatever machine it was pitted against to eventually secure the first-place win.

Filled with fresh enthusiasm, Sinroja headed to the final Sultans of Sprint event at Glemseck 101 in Leonberg, Germany. Sinroja was desperate to secure a podium finish, but it wasn’t going to be easy. “With next to no points on the board other than for participation, we had to go all-in during the final rounds which offered double points,” says Rahul. “So as long as we hit the podium in the final round we knew we would be on the podium for the championship too.”

With so much at stake, all teams pushed their bikes to the limits. This resulted in a few experiencing issues that knocked them out of contention. However, Sinroja’s GT 650 remained problem-free giving them the edge they needed to secure 2nd place in the series and 3rd overall. “The crowd was shocked to see the little Enfield nailing the competition on the strip,” says Rahul. “We were over the moon with the results.”

Royal Enfield Wheels and Waves

The year ahead

On the back of their achievements with the GT 650 drag racer, Sinroja Motorcycles are planning an even bigger 2020. Their goal has always been to offer customers an affordable entry point into the custom world. Through testing and development, this is the year they will make it happen. We’ll be keeping a close eye on their progress as they enter into the realm of short-run production. Their goal is to produce limited-run kits for the Royal Enfield 650 Twins and BMW R Nine T with a focus on customizability and uniqueness. If their past is anything to go by we’re expecting big things from these highly skilled siblings.


Photography by Marc Holstein, Christine Gabler & Gotz Goppert

Royal Enfield Sprint Racer

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