Buell privateer racer up with big hogs

Larry Tate

SPECIAL TO THE STAR

Michael Leon has talent and is dedicated to the sport of Canadian motorcycle road racing .

Twenty-five wins, 47 podium finishes and four regional championships in just over a decade – plus the grit to come back after year off from a serious back injury – certainly proves that.

In recent seasons, he has concentrated on Canadian Thunder and its field full of twin-cylinder brand-name bikes.

His mount is a self-financed Buell XB12R (Buell is the sport bike division of Harley-Davidson).

This year, Leon finished second overall. He came agonizingly close to taking the national championship with one pole position and finishes of a first, two seconds, two thirds, a fifth and a sixth.

Canadian Thunder is the closest thing to "stock" racing you'll get in Canada.

The rules basically mandate air-cooled machines, with two cylinders only. The minimum allowed power-to-weight ratio of 3.8:1 is checked on an official set of scales and horsepower dyno at each race.

Leon's achievements show he's good and that his bike is good. No one wins at Mosport and comes second at Calgary's Race City without serious horsepower.

This rider's results requires a machine that turns and stops exceptionally well.

So how do you turn a street bike into a serious racer? Leon's bike is three years old, and while he's spent a ton of his own money on it, it's hardly a factory effort.

So what's he done to run at the front?

To go racing, the concept is simple: less weight, more power, better and stronger components. The execution, as ever, is where the BS stops and the results begin.

The weight/power thing is unique to Thunder, so the tuner/builder has the option of chasing horsepower at the expense of leaving some weight in place, or leaving the engine alone and chasing grams here and there through the engine and chassis.

It's a different exercise from most race series.

Leon's Buell has measured anywhere from 97 to 103 hp on the dyno over the season, running at about 183 kg, according to engine builder Alex Grupp of Milestone Motorsports in Whitby.

The engine started life as a modified Harley Sportster powerplant. Then "mostly it's blueprinting, very careful assembly," Grupp notes.

He adds that taking a lot of weight out of the drivetrain is probably the biggest job – the crank and anything else inside that moves is lightened and rebalanced.

The transmission gears are back-cut to help shifting.

Up top a Millenium alloy Nikisil 1209 cc cylinder replaces the stock iron-based unit. The head retains the stock cams, and a mild 10.25:1 compression ratio is used.

"No need for huge power with the power/weight ratio thing," says Grupp.

Stock H-D/Buell valve specs are used. Up top, Leon says, "Patrice Juteaux of J Precision just touched up the manifolds to match the ports, and put a light touch on the heads for torque."

At the back end, the Buell's stock belt drive is replaced by a chain system. It's stronger for race use, and allows gearing changes for different tracks that wouldn't be possible with a belt system.

The bolt-on conversion kit is from Hal's H-D in Wisconsin, which works closely with the Buell factory. It includes carriers, axle, idler gear, swingarm, spacers and sprockets.

The brakes are as delivered from Buell, with the exception of a Brembo master cylinder and lever and EBC brake pads.

Elsewhere on the chassis, an Elka shock is fitted out back. Elka, based in Montreal, has also added stiffer fork springs and revalved the front end.

The biggest chassis change is a pair of beautifully-machined new triple clamps. Leon says they retain the same geometry as the stock bike, but have a touch less offset (meaning the fork tubes are closer in to the pivot point of the forks).

"I think it turns a bit more easily."

How do the stock and modified bikes compare, ridden back to back?

Leon's race bike feels remarkably like the stocker, which I rode before getting on his bike. That was a surprise initially, but considering how much of the instrumentation, seating, peg position and so forth carry over, it probably shouldn't have been. The clip-ons are lower and a bit more of a reach.

The reverse shift pattern that Leon prefers wasn't a problem, and Grupp's transmission work is immediately obvious.

The stock XB12R doesn't shift badly, but the race bike is worlds better.

The engine is an immense improvement over the stocker.

Peak power is probably similar, but there's a much wider and friendlier spread, combined with a usefully higher rev limit of about 7800 rpm, compared to 6200 rpm for the stock bike.

The brakes were excellent. I was impressed with the stock ones, but the EBC pads and the Brembo master cylinder and lever arrangement make everything that much better on the racer.

Wheels bike tester Steve Bond, at the same track session, preferred the stock brakes – so personal preference still matters.

I liked Leon's racer a lot, much more than I thought I would.

Riding any well-prepped track bike is fun, but the Buell, despite its brutal look and sound, proved almost delicate and surgical.

The final words from Leon: "I like riding it; it's a fun bike."

I think so, too.

I'm going to have to talk to Home Management about next year's race budget.

More videos from Wheels.ca and our partners