Friday, April 29, 2011

Norton 880 Cafe Racer

LinkNorton 880 Cafe Racer

Norton Commando monoshock conversion
I’ve been watching the progress of the new Norton venture with interest. I have to admit the new bikes don’t quite do it for me, but this one definitely does. It was built by Paul Zuniga, who has been messing around with classic motorcycles (especially old British iron) for over 20 years. For the past five years, Zuniga has been restoring old bikes for a living under the Born Again Bikes moniker, and his Norton ‘Monoshock’ stopped me in my tracks.

The gestation of this bike is convoluted—as seems to be the way with Nortons. “When I spotted a concept image of the proposed ‘New Norton’ in 2001, I knew I had to have one,” says Zuniga. “Kenny Dreer was acquiring the worldwide rights to the Norton name. He came up with a new horizontally split ‘wet sump’ engine, built a couple of test mules, and started taking deposits for the first 100 ‘signature’ edition bikes. My goal was to have one.”

Zuniga got tired of waiting for the new Norton, though. And then heard that Dreer was selling his operation to a buyer in Britain. “So I contacted Kenny and made a deal to buy some of his leftover VR880 stuff. Sometimes you just end up in the right place at the right time; it turned out Kenny still had most of the 951 prototype bike, so we made a deal.”

Zuniga bought several one-off components from the original prototype bike, including the monoshock swingarm, ‘tight tuck’ headers and carbon fiber primary. “He also sold me the blue gas tank, boat-tail seat and side covers, a set of FCR carbs, and most of the major components to build a VR880 engine—including a freshly rebuilt, high-end Baisley-built head and a Spyke electric starter.”

Zuniga’s plan was to take a ’75 Mark III Norton Commando frame and adapt it to accept the Dreer monoshock swingarm. “The adaptation proved to be a bit tricky, but using AutoCad, I was able to come up with a shock-top mount setup that was simpler than the horizontal layout on the original prototype bike.” For the front end, Zuniga plumped for a modern inverted fork, and sourced a nearly-new ZX6 front end locally. “The hardest part of the build was taking a Dreer VR880 front hub and sourcing the appropriate bearings and spacers to accept a modern 1” axle and 300mm full floating brake discs,” says Zuniga.

Zuniga also decided to leave building Dreer’s VR880 engine until later, and installed a complete Norton 850 (electric start) motor. He got an engine and rear end from a friend, and fabricated an electrical panel. He hand-wired the electrics on this bike, hooking up the classic charging system and lighting to a modern Sparx electronic ignition; the big-amp battery needed to crank the starter motor is hidden under the seat hump.

Zuniga decided against using clip-on handlebars: “I intended to put some miles on this bike as a regular rider, and my back can’t handle the boy-racer ergonomic position with clip-ons.” He did, however, install a set of Clubman racing rearset footpegs, using an earlier model right-foot-shift outer transmission cover and shifter shaft. The rest of the project came together pretty quickly and the results are what you see here, an original take on the ‘modern’ Norton Commando. [More details on Paul's project page.]

Tech sheet

Norton 850 Commando Mark III, vertical air-cooled OHV pushrod twin, dry sump
Kehin FCR 35mm flat-slide carbs mounted to 33mm intakes, matched to head
Norton 850 Mark III primary system & electric starter
OEM Norton 850 engine covers, oil pump, transmission & clutch (Sureflex clutch plates)

Norton 850 Commando Mark III frame, modified for upper monoshock mounting
Dreer custom fabricated monoshock swingarm with “big bearing” conversion
Isolastic eng/trans mounting subframe, modified for e-start and swingarm bearings
Kawasaki 636 fork yokes, stem turned to fit OEM Norton steering bearings
Mark III vernier isolastic mount system with Taylor top steady and Eads front steady

Wheels & axles
Excel rims (2.5” F, 3.5” R) laced with Stainless Steel spokes & nipples by Buchanan’s
Custom built rear axle & spacers for OEM Norton Mark III rear hub
Kawasaki 636 front axle with custom built bearings by Buffalo Bearings
Dreer VR880 dual disc front hub & rotor spacers, with custom built axle spacers
Metzeler Lasertec tires: 100/90×19 Front, 120/80×18 Rear

Suspension & Brakes
Front: Showa 41mm fully adjustable (compression, rebound & damping) inverted forks
Rear: KYB fully adjustable, gas charged reservoir rear monoshock
Front: Dual 4-pot Tokiko calipers, 298mm Brembo full-floating rotors, Nissin master cyl.
Rear: 2-pot Nissin caliper, lightened & drilled Norton 280mm rotor, Nissin master cyl.

Cycle Parts
Dreer VR880 matched seat/tail, fuel cell & sidecovers; in Blue with Red & White pinstriping
Dreer ONE-OFF “tuck in” exhaust headers w/ peashooter reverse cone megaphone mufflers
RK 520 chain, Drag Specialties Aero 95mm gas cap assembly, CRG bar-end mirrors
Kawasaki 636 push-pull throttle & clutch lever assembly, Doherty HD cables
OEM Norton footpegs, center stand, oil tank, kickstarter

Electrical Equipment
Sparx 12 volt, 230 watt, 3-phase alternator, Sparx 3-phase regulator/rectifier, H4 halogen headlight
Sparx magnetic trigger electronic ignition, Blue Streak dual-lead 4 ohm, 12 volt ignition coil
Kawasaki 636 handlebar mounted lighting & accessory control switches (2005 spec)

Norton Commando monoshock conversion

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