TURBOCHARGED FJ1200 DIGGER – THE COVER BIKE IN ALL ITS GLORY!

YEARS SPENT RACING FRIGHTENINGLY FAST HIGHEND DRAG BIKES, GOING ABOVE AND BEYOND TO GET THE VERY BEST FROM BOTH YOUR MACHINE AND YOURSELF, LONG DAYS AND NIGHTS MODIFYING/ FETTLING COMPONENTS TO EITHER PERFECTION OR FAILURE, THE HIGHS WHEN IT ALL GOES ABSOLUTELY RIGHT AND YOU POST A TIME YOU’RE PROUD OF, AND THE LOWS WHEN THE MOTOR BREAKS ON THE LINE OR YOU FLUFF A GEAR-CHANGE MID-TRACK, MUST HAVE A CUMULATIVE EFFECT ON YOUR MENTAL HEALTH, IT REALLY MUST…

Why else would you decide to build a motorcycle in a style that’s famous, nay notorious, for being both difficult to ride, and amazingly impractical, and then use your drag racing skills to make it terrifyingly powerful? That’s what Andy Newcombe, one of the leading lights in Comp Bike drag racing in Europe, decided to do over lockdown. He’s been involved in drag racing for over twenty years, starting in Street Bike and progressing to Comp and Funny Bikes, and was a good friend back in the day of the much respected, and much missed, Ian Kilner of Revolution Motorcycles/Diamond Missile fame. “We were the only two daft enough to run Yamahas, I think, but after lots of sleepless nights, and learning how to make my own gearboxes, it went well – Ian GBNF.”

He’d never had any inclination to do a digger, but with a lot of time on his hands, he thought he’d just have a look at old pics of ’70s diggers, Japanese-engined ones, not H-D, and something about those old SOHC 750/4s and Z900s spoke to him. He had a spare FJ1200 motor, or enough parts to build one anyway, knocking about, so he thought, ‘Why not?’ There’s always been a huge crossover, styling wise, between drag bikes and diggers and, looking at a bike like this, that crossover’s very obvious, especially when you look at the spec’ of its engine.

What was, you see, very much part of the initial design was the fact that the bike had, just had, to have a turbocharger. Turbos were, as any student of custom bike history’ll know, very much part of a Jap-engine digger’s make-up back in the day and, as Andy’s more than capable of constructing his own, it’d kind o’ be wrong not to have one, wouldn’t it? The thing is, back in the day the turbo systems they had then were the less efficient, less powerful, and much less useable, draw-through systems that were there, really, just to look good (they worked, obviously, but only when you whacked the throttle wide open), whereas now most modern turbos’re of the blow-through variety that not only produce vastly elevated levels of horsepower, but also’re still as controllable as normal carbs/fuel injection, meaning you get far more power, but it’s useable – not off/on like an old draw-through.

Andy’s engine, a hybrid of FJ1100, FJ1200 and XJR1300 components, runs a blow-through system of his design, using modified FJ1200 carbs, a Turbonetics T4 turbo, and a homemade plenum chamber, and he reports that the only thing he struggled a little with was hiding all the required parts (fuel pumps and regulators, etc.) so that the whole set up looked as slim as it should do. He also says he may’ve overdone the power (210bhp at the back ’oop!), “but, hell, if it doesn’t scare you, it’s not worth riding!” Said, frankly nuts, engine’s held in a lovely one-off frame, goose-necked to give the required stance, again of his own design and construction, based on that of the old diggers, with a stainless steel springer front end (made by him) with a Honda drum hub/ brake laced to a 21-inch rim up front, and a GS750 Suzuki rear wheel (again, with just a drum brake). Just about everything else he made in a 12x6 foot shed, with just basic tools and a small lathe and, all told, the whole build cost less than £800. Yes, you did read that correctly – less than £800 for a bike like this!

Mind you, that’s because so much of it is, as I said, handmade. For example, all of the bodywork was formed and welded by him; the very digger little bellypan that doubles as a threequarters-of-a-gallon extra fuel tank (pumped electronically to the main tank when needed); the wonderfully suitable coffin/ prismic/rocket (call what it you will) main tank; the seat

(covered by his wife Lynsey); the exhaust system; the stainless ’bars; the perfectly perforated swingarm; the de rigueur lockup struts in place of conventional rear shocks; and all the machined brass (pike nuts, axle spacers, swingarm adjusters, etc.); stainless, and alloy parts; and he modified a Sportster rear mudguard into a more trad’ style with its so-Seventies-it-hurts Iron Cross tail light. Similarly, he not only painted the frame white, but also added the perfectly spaced gold pinstripe on it, and laid down the wonderfully geometric candy-blue-(well, four different shades of candy blue actually)-over-silver-base paint with its light blue flake and heavy hologram flake. He also wired and plumbed everything that needed wiring and plumbing, but you’d kind o’ guessed that anyway, hadn’t you?

The whole build took just fourteen weeks, from conception to turning a wheel in anger, and it rides surprisingly well for a style of bike famed for not really doing so. The seating position, he says, is bang on with the pullback ’bars and mid-controls, and the only real downside is the bike’s range, but then that’s not really surprising, is it, when, even with both the top and bottom fuel tanks, it only holds two gallons? You don’t build a bike like this to be practical though, you build it for the look; to be an uber-bling cross between a chopper and a drag bike, and sod the practicalities! He’s done a few hundred miles on it now, visiting local pubs and biker hangouts, and reports that the response to it’s been amazing; some onlookers’ve never heard of a digger, and lots say they don’t like them, but they all point to the turbo and call him mad, which is just fine by him. They also think he’s mad to have a turbo and drum brakes but, as he says: “I never had brakes on the drag strip…”