If anything symbolises the worst aspects of Japanese motorcycle design it has to be some of the unwieldy behemoths unleashed on the public by marketing departments in the late 70's and early 80's. In craven attempts to keep outdoing each other in the "wow" factor, flagship bikes competed for the biggest, widest engine and the highest exhaust pipe count at the cost of handling and manageability, a philosophy resulting in overweight monstrosities like Kawasaki's Z1300. Consider for a moment; you're designing an engine for a motorcycle, a long, thin vehicle. You come up with an in-line six, a long, thin engine. So which way do you put it? Yeah, that's right, across the frame, presumably so it can be air cooled. Then you water cool it. To add insult to injury you then have to fit a an extra gearbox so you can turn the drive through 90 degrees to shaft drive it.
Although a competitor in the silly-engine-with-flimsy-frame stakes, Honda's CBX did at least make a little more sense being air cooled and chain driven, and had a fine motor developing lots of useable grunt even it was a little high on the moving parts count. What a bike the CBX could have been if Honda had taken the suspension a little more seriously, and had access to modern tyres and brakes.
Enter Heath, long time CBX fan and currently owner of three of the beasts, whose wealth of experience with these big sixes has established him as something of a CBX guru. This is his streetbike which he has now owned for the last twelve years. Yes, that's twelve years, long enough for empires to rise and fall and economies boom and bust.
For the first seven of those years the bike was more or less stock, having started life as a 1981 model, and Heath used it as a hack while he built more and more radical CBX based specials, culminating in the now notorious pink turbo-charged monster that has now passed into legend in the Bradford area. When the time came for this bike to meet the hacksaw Heath had a pretty good idea of precisely what he wanted.
He started by junking the stock suspension, wheels and brakes and set about looking for something better. He's in the enviable position of being co-proprietor of Crossleys Breakers in Bradford, and was therefore perfectly placed to spot tasty items on bikes that came through the shop for breaking, and mixing and matching from the best available parts. The wheels, brakes and forks are all from a Yamaha TDM 850 which gave the bike the tall stance he was looking for as well as four pot calipers, floating discs and modern tyres. Surprisingly the Yamaha front end, which is almost 4" longer than the CBX, bolted straight into the Honda frame, the only modification being to the top steering head bearing which had to be machined by 2mm to fit.
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With the front end decided on and fitted, Heath then turned his attention to the back of the bike, which was to present more of a challenge. He wanted a rising rate monoshock that would not only perform well but match the tall geometry at the front. Rejecting Honda's own Pro-Link set up (did someone say "too flimsy?"), Heath offered up the swingarm assembly from a Kawasaki GPZ1000RX and found, to his great delight, that the pivot was compatible with the Honda frame. The top rocker mounting presented a much tougher problem, and he eventually had to fabricate and weld on two triangulated box section housings to take the pivot mounting spacers, which were slugged and welded into the frame. Careful attention to shock angle and pivots gave Heath the look he was after, and created a well balanced geometry for the whole bike.
Fitting the Yamaha wheel was a relatively easy task by comparison; once new spacers had been carefully measured and made to line up the wheels, the sprocket carrier was turned to bring the sprockets into line and the whole plot was bolted together. The rear caliper torque mounting was, he admits, a bit of a lash-up at the time, "But it worked well so I left it alone". The result of all this careful attention to geometry was a much taller bike with a wheelbase identical to a stock CBX.
The big six cylinder engine was stripped and blueprinted by Heath, and has a couple of internal modifications to help it breathe better (he wouldn't say more). He rebuilt it with a WISECO big bore kit which takes the motor out to 1170cc, and fitted Carillo con-rods which, although not strictly necessary on a street bike, gives him peace of mind while riding the bike hard. The only other modifications are K&N air filters (with "some up-jetting") and open pipes by Honda Motor Co. "and entropy". Although the bike hasn't been on a dyno in this guise he estimates power output to be around 125 B.H.P.
One other area that Heath finds wanting in Honda's original design is the cable operated clutch, which is heavy enough to require a grip like Godzilla around town. His answer is the hydraulic clutch conversion. The original clutch lifter has been removed and it's holes welded up. The clutch case was then machined to take the clutch lifter mechanism from a Kawasaki GPZ1000RX, with an extra alloy boss welded inside the casing to increase it's rigidity. After spending some time experimenting to find the optimum pushrod length the system now works well, and has the benefit of being self-adjusting. I can certainly confirm the lightness of the clutch action, it made the hydraulic clutch on my FJ1200 feel positively heavy by comparison.
Cosmetically, Heath pursed the mammoth trail bike theme by fitting an old XL250 tail light onto the rear mudguard from an old SOHC 750 Honda, which was welded onto the rear frame loop so it could be moulded in before painting. The front fairing is a heavily modified Kawasaki KLE 500 item which carries the basic instrumentation on a hand-made alloy dash panel. The seat was upholstered by local bike seat wizard Tony Archer, and the twin-pack paint was applied, with the computer graphics, by "a lad up the road". Heath describes the colour, rather prosaically, as "red".
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As you can well imagine, this is not a slow motorcycle, and Heath has taken the bike up the dragstrip several times at the Bulldog , and has E.T. slips showing 12.3 seconds elapsed with terminals in the region of 119.
Amazingly, after all this time with the big six cylinder Hondas, his next project came as something of a surprise when he unveiled a half-built Triumph Speed Triple sitting in a Spondon style alloy beam frame with a turbocharger. When I asked him why he'd chosen a triple after years of riding sixes he just shrugged and mumbled something about there being only half as many parts, which I suppose makes some kind of sense. If it's half as good a bike as this CBX it will be some motorcycle.
Crossleys Breakers are on (01274) 395559.
Rod Gibson