Wild File: Honda CBX Racebike - 666 The Number of The Beast

Riding Roland Skate's Honda CBX six-cylinder superbike

There can't be many devices racing anywhere in the world today as improbable as Aussie Roland Skate's Honda CBX six-cylinder superbike universally known as "The Beast." Ridden by Michael Dibb to a hat-trick of third-place finishes in the Vintage Superbike support races at the 2010 World Superbike round at Phillip Island, the Beast was no more than two hundredths of a second away from grabbing second place from Karl Corp's four-cylinder Kawasaki KZ1000. In just the 18 months since it made its debut in the Australian MotoGP support races at Phillip Island in 2008, the Skate six and Dibb have become one of the most popular entrants in the category for air-cooled multi-cylinder superbikes officially labelled as "Post-Classic Unlimited Period 5", but best known everywhere as Vintage Superbike.

The chance to ride Skate's Honda CBX at the Broadford Bike Bonanza gave me a chance to find out what an improbably good-handling package it is. Broadford's tight 1.3-mile configuration with many blind bends and elevation changes posed a severe test for such a bulky motorcycle. Especially when the 130 horsepower at 9600 rpm delivered by the tuned big-bore 1147cc 24-valve motor is transmitted through a scrawny 4.50-inch-wide rear wheel, the widest allowed in Post-Classic racing. At least the MA (Motorcycling Australia) rulemakers permit slick tires to help hook up the horsepower, in recognition of the 1300cc top limit for Historic racing's big-bike category.

A self-employed carpenter from the scenic Yarra Valley east of Melbourne, Skate has been a CBX fan since 1982. That's when he bought his first one, a well-used ex-drag racer that he rode continuously until it turned into a ratbike. "I just fell in love with it because it gave so much performance - and especially so much fun - in return for so little attention," reminisced Skate.

"I began doing track days and eventually plucked up the courage to go racing with it, so that's when I thought I better give it a bit of TLC! After that first race at Mount Gambier in 1994, I've been progressively modifying it on and off ever since." Even so, a five-year layoff after dropping a valve in practice at the 2003 Island Classic might have become permanent if not for meeting racer Michael Dibb in 2007, a fellow Hartwell Club member. Skate decided to rebuild the CBX as a Vintage Superbike for Dibb to ride. "People used to rubbish the CBX all the time when I used to race it, saying it'd never ever make a racebike," recalled Skate. "But I knew the bike had it in it to be successful if I got a good rider aboard it - and I reckoned Mick had the potential."

Skate had previously promised to help Mal Bristow, a fellow member of the Australian CBX Owners Club in Perth, build a CBX racer and had been sending him parts for the project - only for Bristow sadly to pass away before it had even got started. "Mal's widow Val insisted on sending me everything he'd collected, and told me to build a bike in his memory, because it's what Mal had wanted to do himself," recalls Skate. "That's why his name's on the bike today, together with their family's freight forwarding firm, PowerHouse Clearances. The Beast wouldn't exist if not for them. Between Mal's collection of parts and my blown-up bike, we had enough to build one good racebike and a spare engine." A pair of shakedown club races with a lightly tuned motor taught Dibb how to ride the bike, but ground clearance problems with the stock frame and slick tires were an issue. However, help was at hand in the shape of American CBX guru Tom Marquardt, who brought his U.S.-spec bike over for the 2008 Island Classic and ended up crashing it, suffering injuries which necessitated a three-week stay for him and his wife as Skate family guests. In return for their hospitality, Marquardt insisted on taking Skate's stock CBX frame home with him, and modifying it to the same spec as his own CBX, an Endurance racer he built back in 1980, and has been racing successfully in the USA ever since.

The Beast's debut in the trio of Vintage Superbike support races at the Australian MotoGP in October 2008 was straight out of a movie script. "We finished the bike at 5:00 a.m. on the morning of qualifying," remembers Skate with a smile. "It had zero miles under its wheels apart from a quick run up and down the road to make sure it changed gears, and Mick had never ridden it before in that configuration; it was quite a bit more powerful and had totally different chassis geometry from the stock bike he'd ridden before. We went straight from the workshop to the track, and he qualified the CBX in fifth place on a 40-bike grid with all the stars like Phillis and Campbell there, as well as the Irving Vincent - it was just amazing! And it was an instant crowd-pleaser; we had to fence off the bike to have room to work on it." When Dibb finished fifth in the first of the trio of races in spite of having no fourth gear, it was the icing on the cake.

To create the Stage Three version of the bike I rode at Broadford, still exactly as it left the track after the Phillip Island races a month before, Skate took a stock CBX engine weighing 225 pounds with carbs, junked the generator and starter motor assembly, and added a 30mm extension to the oil sump, making room for six liters of Motul lubricant instead of the normal 4.5-liter capacity. Skate also uprated the oil pump and fitted a bigger HRC oil cooler from an RCB1100 racekit. Carrillo steel rods carry 3mm-over Wiseco pistons to punch the motor out to 1147cc via 67.5 x 53.4 mm dimensions (versus the stock 1047cc), and compression has been raised to a not exactly heady 10.5:1, up from the lowly stock 9.3:1.

The CBX motor has central chain drive to the twin overhead Web Cam racing camshafts. The camchain operates the exhaust camshaft directly, with drive then transmitted to the inlet cam via a short secondary chain. Instead of the original two dozen 25mm inlet/22mm exhaust valves in the 24-valve cylinder head, which has been ported and gas-flowed by DeWith Racing with a bigger squish band machined in, Skate uses Chinese-made oversize stainless steel valves measuring 26.5mm/23mm, each fitted with dual Kibblewhite Precision springs from California, with their operation converted to a shim-under-bucket setup, using 13mm Kawasaki shims and specially machined retainers to hold them in there. "We've tried heaps of different American race cams, some with very high lift, but these Web Cams are the best," says Skate. "They're not as aggressive as some we've used. We used street cams for quite a while, because they'd make the bike more rideable even if the power wasn't so great, but these Web Cams are the best compromise. They're still pretty tractable and give us 130 horsepower at the rear wheel at 9600 rpm with the Megacycle stainless steel 6-into-2 exhaust, but with quite a nice spread of power." Peak torque is 72 ft-lb at 8000 rpm, and ignition comes courtesy of a Dyna CDI and coils, with a 10,500 rpm rev limiter programmed in.

Six 31mm Keihin CR-S smoothbores replace the stock 28mm CV carbs, though these do require 6mm to be ground off the top of the crankcases and the top frame tubes flattened a little to accommodate them. The sextet takes a lot of setting up to get them properly balanced, and flatslides are forbidden under Post-Classic rules, laments Roland, who'd like the better acceleration they supply to get his heavy bike moving out of turns. The stock five-speed gearbox has undercut gears, driven via a Barnett Kevlar clutch with lightweight aluminum basket.

The Beast weighs in at 500 pounds ready to roll, with that weight distributed 46/54 percent rearwards via the NZ-built McIntosh chromoly swingarm with underside bracing and twin Wilbers/WP fully adjustable piggyback shocks (the 1980 Post-Classic cutoff originally meant Skate had to use the first-version CBX twin-shock frame). That heft gets stopped by twin front 300mm floating Ford McKernan 6mm-thick cast iron discs gripped by twin-piston Brembo calipers sourced from a wrecked Benelli 900 Sei (ironically, another inline six) with a tiny 178mm Kawasaki rear disc with single-piston Hyosung caliper. The 17-inch Dunlop slicks are slung on a 3.50-inch front wheel off a Honda VTR1000, matched to a 4.50-inch rear from a Kawasaki ZZR600.

However, a key ingredient in The Beast's success has been the revised geometry of the Marquardt/Bishop frame, which originally saw the stock CBX triple backbone chassis revamped in the USA to position the engine 25mm higher and 15mm further forward. At the same time, the upper rear shock mountings were repositioned 30mm lower to give a taller rear ride height. "However, this still didn't give enough ground clearance, as Mick was grinding out the crank end caps even with Tom's frame," says Skate. "So we had Ted Bishop roll the engine back further on his copy, lifting it at the front by 15mm to give us more room. Now he doesn't ground the bike out anywhere!" The Marquardt frame uses a 23-degree head angle for the 39mm Showa fork off a later Pro-Link model, rather than the rangy stock 27.5-degree steering geometry; having the fork tubes raised 20mm through the stock triple clamps delivers a tight 89mm of trail.

You need to tiptoe to climb aboard Skate's CBX, thanks to the tall rear ride height needed for ground clearance, and the high seat pushes your body weight forward onto the wide-spread Tingate clip-on bars. These are set very flat, a key element in providing the needed leverage to steer the big Honda quickly. I'll admit I had to work up gradually to flicking the bike into turns; even though Dibb told me he doesn't grind the engine cases any more, I was worried that my extra kilos would invite ground contact. I soon found that within the limits of the skinny Dunlop tires, the CBX now has lots of ground clearance, and that in spite of the adverse weight distribution, there's good front-end grip.

Thanks to the altered steering geometry, you soon forget that you're riding such a wide six-cylinder package, because it doesn't feel that bulky on the move. The CBX steers far more sweetly and precisely than I expected in slower corners, turning in nicely without a lot of effort. Braking from high speed was good too, especially taking into account all that extra weight; the locally made Ford McKernan cast iron discs and Brembo calipers giving far more bite than comparable Japanese stainless steel rotors of the period. The Beast is very stable on the brakes, with that rearward weight bias helping prevent any rear wheel lift.

But that silky-smooth engine is a surprise, too, because its user-friendly power delivery makes it easier to ride in tight, twisty track sections than its more potent but peakier four-cylinder rivals. It really comes alive from 5800 rpm upwards (as shown on the compact but mainly illegible Acewell digital tacho mounted to the right of the white-faced oil pressure gauge), but then the power continues to build in totally linear mode, past the peak torque mark of 7200 rpm up to the 10,400 rpm rev limiter. The Megacycle exhaust's twin cans produce more of a mellifluous burble than the six-cylinder scream of an open-piped multi-cylinder GP racer. Dibb told me it really pays to redline the motor in each gear, waiting until the engine flutters before grabbing another gear on the race-pattern shifter.

However, that progressive build of power is too friendly at present; the CBX actually needs more acceleration, especially out of a slow corner where the engine inertia takes time to overcome. Those three third-place finishes by just hundredths of a second to a four-cylinder Kawasaki in the SBK support races were surely the result of the CBX not getting the same degree of drive out of the last, fast fourth-gear turn as the KZ1000. Fix that, and Dibb will be surely be looking at winning races.

The race motor is most effective when you modulate the throttle while searching for grip on a slippery track in the morning. Pouring on the power while cranked over didn't faze the CBX chassis - provided the track was smooth. Having the handling go haywire by hitting the bump on the Broadford back straight each lap gave me a good idea of what the CBX was like for Dibb to hold on to as it tried to tie itself in knots. Same thing for me cresting the hill leading down onto the straight each lap - the CBX would shake the bars violently from side to side before the front wheel touched down, but never managed to get out of hand - somehow it straightened itself out each time. It looked more spectacular than it really was; good enough to earn The Beast a round of applause from spectators as we headed back to the pits.

"I built the Beast in 1993, but it's really only been in the last two years that we've achieved what we set out to do, and scared the established players thanks to a huge all-round effort," states Roland Skate. "If I die now, I'm content! Although on saying that, I still have some ideas that I'd like to bring to fruition, though I've shelved the plans for gear-driven cams, now that I can blame the engine case stud for the Broadford blowup, instead of a dodgy cam chain. But now I'm aiming to build a 1233cc methanol-fueled Pro-Link framed Beast, and let's see if that gets us to the finish line first!"