A Bonneville For Bonneville

Riding South Bay Triumph's Record-Setting Turbo Twin

By Alan Cathcart, Photography by Phil Hawkins, Andrew Cathcart, Steve Bohn

Triumph motorcycles have a long and distinguished history at Utah's Bonneville Salt Flats. In fact, its most iconic model is named the Bonneville, in honor of an outright motorcycle speed record set by Texan Johnny Allen in his Triumph streamliner in 1955. Matt Capri has a colorful history on the salt as well. The founder of BMW tuning house Luftmeister, Capri set his first speed records at Bonneville in the '80s, riding various normally aspirated and turbocharged BMWs. He opened his South Bay Triumph dealership in '95 and began setting records with the British brand shortly thereafter, including one in excess of 200 mph on a turbocharged Daytona.

With such a proven track record building performance bikes, and such a close relationship with Triumph, it was only a matter of time before Capri turned his tuning talents to the new-generation Bonneville. And, given his history of record-breaking turbo bikes, it was inevitable he would build a turbo Bonneville. Two years ago he finally did, after a few years spent collecting parts for the special project. "I tried to get support to do this earlier, but we couldn't get any help," Capri says. "No one thought you could make a twin boost, so I decided to do it myself."

Capri's first attempt debuted at Bonneville in August '08. It was entered in the 1000 PB-G class (1000cc Production Blown Gasoline), with Capri in the saddle. He only completed two passes that year, but went fast enough to establish a new AMA national class record of 161.288 mph. The bike actually went 168 mph on the first run, but the two-way average suffered when Capri's loose-fitting leathers got sucked into the turbo intake on the return run, reducing boost. Capri then handed the bike over to a lighter, more aerodynamic rider in an attempt to raise the record. That effort ended badly after the hired jockey held the engine against its rev limiter too long and cracked the cylinder head.

Capri might have failed to find the bike's ultimate top speed, but he did satisfy another objective by setting a record at Bonneville aboard a Triumph Bonneville on the eve of that model's 50th anniversary. He also honored the late, great Bonneville legend Don Vesco's rule: "You shall not leave the salt flats until you have broken all of your parts." Mission accomplished, then.

In actuality, Capri was just getting started. He returned to his shop with the goal of coaxing more power and greater reliability from the turbo Bonneville. Capri identified a special opportunity in '09, following the FIM's radical overhaul of its world speed record categories. Previously, categories were defined by engine displacement only. Number of cylinders was irrelevant and, as a result, nearly every record from 750-2000cc was the property of a four-cylinder Suzuki. New rules, however, would take the number of cylinders into account. This revitalized the sport, and delivered countless new record opportunities to Capri and others competing with European and American twins.

Capri zeroed in on the FIM world record for 1000cc Twin Cylinder Blown Unstreamlined motorcycles. With an added year's worth of development on the Mickey Cohen Motorsports dyno, the turbo Bonneville was now producing 230 horsepower at the rear wheel. Since yours truly already had an FIM international competition license, Capri asked me to ride the bike, while he led a support crew including Roger Russell and my son Andrew.

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