GRR by XTR Pepo…
Royal Enfield named their new single-cylinder streetbike the Guerrilla 450 because it breaks with tradition. It’s significantly more modern in style and design than most of the brand’s machines, featuring the liquid-cooled 452cc DOHC single-cylinder “Sherpa” engine from the Himalayan 450 — the first liquid-cooled powerplant in the brand’s 125-year history.
The engine only makes around 40 brake horsepower, but 70% of peak torque is available from 3000 rpm to 8000 rpm. Combine that midrange punch with a new steel tube chassis, Showa suspension, and excellent ABS brakes, and the GRR 450 is incredibly well-balanced.
“While I love liter-class hypersports pushing upwards of 200 horsepower as much as the next guy, performance can mean different things to different people. For me, my definition of performance is more about balance—a lightweight, flickable chassis, mated to a peppy engine that provides just the right amount of power and torque to have a good time out on the twisties. Little did I know that with the Royal Enfield Guerrilla 450, I’d find just that.” –RideApart
Any time a new model debuts from a brand like Royal Enfield, which supports the custom world, it’s interesting to see what builders will do with it. RE commissioned one of the world’s “master constructors,” Pepo Rosell of XTR Pepo, to build the machine you see here.
“I wanted to make a supermono race bike with an endurance look. The design was inspired by the Pantah 821 project I made in 2017 with the same designer, Alberto Caimi.”
Nicknamed the “GRR” after the factory code for the Guerrilla 450, this supermono has the signature race-inspired design for which XTR Pepo is so well known. Highlights include Aprilia forks with CNC yokes, forged aluminum Dymag wheels, a modified Aprilia RS 660 aluminum swingarm with Nitron rear shock, custom subframe, and fiberglass bodywork designed by Futura 2000 and Alberto Caimi of Turin, fabricated by Crazy Bike and painted by Artenruta.
The bike now weight just 131 kilograms wet (oil, coolant, 5 liters of fuel, etc.), which is more than 35 kilograms (77 pounds) lighter than the original — lithe!
The result is quite unlike any Guerrilla 450 (or Royal Enfield, period) we’ve ever seen — a single-cylinder supermono that looks ready to blaze the track. Below is a full build sheet and more builds from XTR Pepo.
Build Sheet
Donor bike: Royal Enfield Guerrilla 450
Modified frame
XTR Subframe
XTR front fairing support
Aprilia Falco 1000 fork
S&P CNC machined triple clamps
DISCACCIATI brake rotors
DISCACCIATI radial front brake pump PR 19
DISCACCIATI clutch commando
XTR clip-ons
DOMINO Grips
XTR plexiglass
XTR front light
DYMAG aluminum forged front and rear wheels
CONTINENTAL MOTO SPAIN tires CONTI MOTO SPORT ATTACK 2 120/70-7 & 160 /60-17
Modified JT front sprocket
TALON aluminum rear sprocket
REGINA 520 chain gold
DUCABIKE CNC machined regulable footrest
Brembo rear brake pump and caliper
NG rear brake rotor
Modified Aprilia RS 660 aluminum swingarm
XTR carbon fiber rear mudguard and swingarm protectors
NITRON rear shock
Lipo Battery
LED rear light
BODYWORK ( fuel tank, solo seat, front fairing and belly pan) in glass fiber designed by FUTURA 2000 and ALBERTO CAIMI (Turin). Fabricated by Crazy Bike
ARTENRUTA painting
XTR carbon fiber airbox
X PIPE exhaust system
SPARK titanium/carbon silencer
XTR upholstery
I want to thank MOTOS ASCARI for his logistic support and help.
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Pictures by Carrascosa
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