Custom Moto Guzzi Café Racer

A trip to Spain ensued, including a visit to Segarra’s shop, Team Guzzi Motobox, and vintage racing at Cartagena, which includes classic endurance racing, an increasingly popular category in European vintage racing. This kindled the idea of producing something that was “a cross between what I’d seen at Cartagena” and bikes from the early years of European endurance racing of the type seen in the great Montjuich Park and Bol d’Or races from the late 1960s through the 1970s. “It was an interesting time for motorcycles, because pretty much anything went for a while there,” George says.

Yet while Moto Guzzi had a strong tradition in racing, they were mostly absent from endurance racing, at least in an official capacity. “They tried it for a year, 1969 I think, then backed out,” George says, “so I decided to build a Segarra Replica. It was a classic case of ‘what happens when you heat the garage.’ The idea was to create a bike that was a combination of those two things. Manel’s work is a kind of a template for what [a 1970s Guzzi endurance racer] might look like.”

One of the signature features on Segarra’s bikes is the deletion of the bottom frame rails from the classic Lino Tonti Guzzi frame, a design first used on the immortal V7 Sport of 1971. “The first thing to do was get hold of a frame, and the one that just happened to show up was an 850T. It didn’t really matter because the Tonti frames were mostly the same. They’re a really wonderful piece of engineering,” George says.

A useful feature for the home mechanic — and custom builder — is that the bottom rails on Tonti frames are bolted in place, which makes it easy to remove the engine/transmission assembly. That also lessens the level of surgery needed in building the sort of special George did.

“The next thing I got were forks, a set from a Sport 1100. I wanted a little quicker steering. The standard steering angle (for an 850T) is 28 degrees. They tend to be pretty slow steering. Wonderfully stable, but heavy,” George says. To tighten up the steering angle to 25.5 degrees, the same as the Sport 1100, George “cut and shut” the frame gusseting. Trail is just shy of four inches, a good specification for stability.

Motivating the mass

“I got the engine from a friend,” George says. “He picked it up at a garage sale in North Carolina, it’s from a 1979 1000SP. I didn’t go to a lot of extremes. There’s no crankshaft lightening, no additional ‘under the pistons’ oil squirting. The whole thing is pretty stock in the bottom end.” But it was carefully balanced by High Performance Engines in Burnaby, British Columbia, Canada.

Next, George installed a Megacycle X10 cam, their hottest street shaft, together with a windage tray in the crankcase to keep the oil in the extra-deep oil pan from flying around and robbing power, and an adapter for a later-style oil filter. The cylinders started out as chrome-plated 850T items, bored out to the maximum considered safe, then Nikasil coated. “The pistons are one-off from JE Pistons, crowned and sized to the bore,” George says.

All of the top-end engine work was done with the help of New York’s Mike Rich, a name well known to those in the vintage racing game. Mike also modified a set of Guzzi Convert heads that George found on eBay to Le Mans 1 specification, machining out the combustion chamber to accept the Le Mans’ bigger valves and seats, then drilling and threading for a second spark plug. “The Le Mans 1 head and all the other smaller valve heads are the same casting, they’re just machined differently,” George says. The valves are Black Diamond, and springs are Mike Rich items. A pair of 40mm Dell’Ortos feed fuel and air, exhausting through stainless headers fabricated by Paul Brodie of Flashback Fabrications, mated to a modified Scorpion muffler intended for a Suzuki GSXR 1000.

Fabrication

The interchangeability of Guzzi parts helped considerably with the café project, which uses a modern V11 Sport clutch, an absolutely stock five-speed Guzzi gearbox and 1000SP final drive — though each of the last two items was carefully overhauled and assembled by Charley Cole of Zydeco Racing.

Completing the installation is a sturdy aluminum plate replacing the battery tray and tying the engine to the frame seat tubes. This extra strengthening is necessary thanks to the removal of the bottom frame rails, and is a Segarra part. Segarra also provided the seat/gas tank unit, which on Segarra’s own bikes is a one-piece unit. As the cost of shipping the combined unit from Spain was prohibitive, Segarra separated them. George also removed the rear subframe loop behind the shock mounts — its only function was to support the (also ditched) rear fender.

“Most of the metal fabrication I did myself,” George says. “Paint, welding and fiberglass I left to others. My fabrication experience is from aircraft, so that’s reflected in the way it’s built. Much of what most people would have welded, I riveted together. It makes for a lighter structure, generally.”

The gas tank, tail section and matching period fairing were painted V11 “Tenni” green, the color of the limited edition 1971 V7 Sport dedicated to Omobono Tenni, 1937 250cc world champion and Isle of Man TT winner for Guzzi. “I really liked the stories of the Guzzi race team,” George says, “with their hand-formed dustbin fairings and so on. And when it came to giving them a coat of paint, the cheap stuff they could get their hands on was zinc chromate, your basic green airplane primer. And that became their race color!” The frame-mounted fairing is from Airtech in California and based on a Magni design for the V11 Sport.

“I wanted spoke wheels,” George says, “and the only spoke wheels from that era that were compatible with the axle spacing were from the T3.” So new Excel rims, wider to allow a fatter back tire, were laced to T3 hubs. Stock two-pot Brembo front brakes take care of the front, and the rear brake, also a Brembo from Yoyodyne, is anchored to the frame by a trick-looking parallel arm.

George designed his own wiring harness and assembled it to aircraft spec using custom color-coded wire from Rhode Island Wiring Service and period connectors from Vintage Connections. All lights except the Kisan modulated headlight are LEDs, and the electrical spec also includes … well, let’s call them electronic counter-measures to combat speed detection equipment, and illegal in some states.

The neat speedo/tach combo came from now defunct Moto Spezial, as did the custom gearshift linkage and carburetor cable guides. George also credits help from MG Cycle and Moto Guzzi Classics. Rearset footpegs are from Motobits in Seattle.

On the road

So how does it work? “The handling is really nice. It’s quicker, yet stable,” says George. “The forks are taking a lot of work [to get right], however. It’s quite uncomfortable to ride, quite bouncy.” George has tried different spring rates and oil weights without much improvement and plans to tap into some ideas for improving the damping with valving from later Guzzis, a modification being developed by Moto International. Rear shocks are YSS sourced from Guzzi Tech, though George plans to change these to Ikons or maybe Ohlins.

Early road testing showed up a couple of issues. First, the engine was pushing a considerable amount of emulsified oil into the catch tank through the crankcase breather. Using principles developed by Australian engine breathing guru Rex Bunn, George designed his own system that eliminated the problem. It was also pretty clear that carburetor settings were incorrect, based on very high fuel consumption. Dyno tuning showed something of a dip in the torque curve, which George plans to address with changes to cam timing — not so easy on a Guzzi, which has its camshaft buried inside the crankcase.

George also plans to experiment with “valve ditching,” a technique developed in the 1930s to improve directional airflow in combustion chambers. The idea is to machine a triangular-section annular groove in the valve head with the groove cut so as to perturb or baulk mixture flowing back over intake or exhaust valves. Vintage Triumph racer and AMA speed record holder Tom Mellor, a friend of George’s, has had success using this technique to damp out “dips” in the torque curve. Other options George plans to try include extending the intake tracts, using a balance tube between the intake manifolds, or even a redesign of the exhaust system.

“This motorcycle is a brute,” George says. “There’s nothing subtle about it. It’s kinda loud, but in a good way — or as Tom Waits put it, ‘Like the ghost of Gene Krupa … with glasspacks.’ It’s a true hooligan machine.” MC

Parts
• High Performance Engines
• Flashback Fabrications
• Zydeco Racing
• Airtech
• Yoyodyne
• Rhode Island Wiring Service
• Vintage Connections
• MG Cycle
• Moto Guzzi Classics
• Motobits
• Guzzi Tech

Read more:
• Tom Mellor’s Record Breaking 1969 Triumph Trident T150