From Radical Speedshop: “The most powerful and light Guzzi ever…”
Radical Speedshop is a family-run German workshop with a twin-piston Italian heart. The Bronolds — Stefan Sr., Stefan Jr., and Simon — build Guzzi customs, race bikes, and manufacture parts for the world’s Guzzisti to modify their own bikes. Says Stefan Bronold, Jr.:
“Somewhere down the road of being obsessed with motorcycles we felt the Italian heartbeat — shortly with Ducatis and then — unstoppable — Moto Guzzi…”
They’re also heavily involved in the European sprint racing series — formerly Sultans of Sprint and now the Rocket Race Club — where air-cooled twins from garages and workshops all over the continent compete in 1/8-mile drag races, often during big events like EIMCA and Glemseck 101.
In 2021, we featured Radical Speedshop’s “NOSferatu” — a heavily-modified Moto Guzzi Quota with a bored-out engine making 180-220 hp with nitrous-oxide injection — which led to “NOSferatwo,” which had a completely custom frame, 1400cc Griso 8-valve engine, and NOS injection.
Now the Bronalds are back with this 1700cc Moto Guzzi “Cento Anni,” a street-legal torque monster built to celebrate the 100th anniversary of Moto Guzzi’s Mandello factory. Radical Speedshop set a very high bar for the build — but if anyone in the world was up to the task, it was the Bronolds:
“The concept was to build the most powerful and light Guzzi ever.”
The bike has been built on a modified ’74 Bellagio chassis with Wilbers suspension, Beringer brakes, Rotobox carbon wheels, and an arsenal of bespoke parts from the workshop’s CNC machine. The alloy bodywork was shaped in-house before the Bronolds’ friend Herbert Franz undertook a masterpiece of airbrushing — laying down the likeness of Guzzi founders Carlo Guzzi and Giorgio Parodi, Guzzi world champions (Bruno Ruffo, Fergus Anderson, Bill Lomas, Keith Campbell), and even the entrance of the Moto Guzzi factory in Mandello — a job that took him 10 months!
Then there’s the engine. Though the Guzzi V-twin may look stock on the outside, the internals are completely custom. It’s been bored to the maximum — 108mm — and given an 11mm stroker crank for the largest displacement possible: 1700cc.
“It’s at 164 HP and 202NM [149 ft-lbs] torque — measured at clutch. The bike with 10 liters of fuel weighs 168 kg [370 lbs]…”
The “Cento Anni” made quite the showing at the Glemseck 101 International Sprint — “Europe’s Bggest Café Racer And Sprint Race” — where Stefan Sr. rode the bike to victory, beating a modified Triumph Speed Triple in the finals! Overall, it took 2nd in the Rocket Race Club series.
Below, we talk to the Bronolds for the full story on their 1700cc “Real Monster Guzzi.”
Moto Guzzi MGR1700: Builder Interview
• What class was the bike built to race in?
The bike wasn’t built for any class; it’s our personal bike for normal street use. Built to celebrate 100 years of Moto Guzzi with all the world champions, Carlo Guzzi, and Mr. Parodi airbrushed on the tank.
• What was the design concept and what influenced the build?
The concept was to build the most powerful and light Guzzi ever. Therefore we did a new crank with a longer stroke because the bore is limited at 108mm — to have 1700cc, we must increase the stroke from 81.2mm to 92.6mm and bore from 95mm to max 108mm.
• Does the bike have a nickname?
Our race name at Glemseck 101 was “Cento Anni” to celebrate the 100-year annniversary, but most people called the bike the “Torquemonster” and we’ve published sometimes under the name #realmonsterguzzi.
• What custom work was done to the bike?
We did the alloy tank and seat, customized the frame from a Bellagio for better stance, footrests, fork triples, and many, many other parts made in-house on our CNC machine. Wilbers suspension, Beringer brakes, Rotobox carbon wheels.
The most work was done on the engine. It cost a lot of time and nothing inside the engine case is original — also the engine cases had to be modified. But when you look athe outside of the engine, is still looks like it’s original.
It has a new crankshaft with 11mm bigger hub, new rods, forged pistons 108mm bore, special camshafts. Everything constructed and produced ourselves. The bike at moment runs with Keihin FCR41 carburetors. It’s at 164 HP and 202NM torque — measured at clutch. The bike with 10 liters of fuel weighs 168 kg…
Suspension is Wilbers front and rear. Electrics are minimal, done by us. Brakes are Beringer and carbon wheels are from Rotobox. Full Titan exhaust system (total weight 3kg). Airbrush is done freehand by our dear friend Herbert Franz — it shows all the Guzzi world champs, Mr. Parodi and Mr. Carlo Guzzi, and also the entry of the Guzzi factory in Mandello.
At Glemseck 101, we won the international sprint and was second place in Rocket Race Club with this bike. International Sprint, these are the most powerful bikes and we’re proud to win against many strong bikes and professional riders.
• Can you tell us what it’s like to ride?
The bike is street legal. Sure it wants to go fast, but it’s also very smooth to ride on normal legal streets.
• Was there anything done during this build that you are particularly proud of?
Sure we are proud to have the biggest air-cooled engine from a European maker. Also the airbrush is an artwork and our friend Herbert Franz needed 10 months to finish it.