Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/128385
Pat Hennen's Suzuki XR23B (Above) A pair of sidemount carbs feed rotary valves for right-side cylinders of this "square four." Shirts or skins, the XR23 appears outwardly similar ta the 500cc Suzuki GP machines of the day. As Cathcart found out, cracking the throttle told a much different stary. form I was deputed to run it in for Wilson at the Coupes Moto Legende meeting at Montlhery in 200 I. Later that year, Wilson and Everett brought it to Snetterton for me to ride in something approaching anger, only for it to run a crank after just half a dozen laps. At that stage, Wilson believed it to be one of the Sheene bikes, hence the number- seven race number - but Everett later acquired the prized Heron Suzuki race records courtesy of former team manager, the late Rex White, and further research revealed that this was Hennen's 1978 XR23A, updated to "B"-spec motorwise for Hartog the follOwing year. Suitably rebuilt by Racing Restorations, and now bearing Hennen's number-23 livery, it was a case of third-time's-Iucky at a sunny Misano, a track better suited to such a longlegged bike, even if still overgeared on the shortest ratios in the spares box, so I could only grab a true fifth gear down the main straight in either of my two 20-minute sessions on the bike. The first problem I ran into on the bike was the strange and ungainly riding position, where thanks to the fat exhaust pipes behind your heels, you can't actually put your toes on the footrests - you have to ride with your insteps on the pegs, which feels really strange, quite apart from the fact you're wedged in place. This means you can't move easily from side to side on the bike, and you especially can't hang off it, because you can't get your toes on the rests. Hmm... No wonder Sheene made them swap back to the old pipes. I guess noise enforcement was still in its infancy back then. The screen is quite wide, giving good protection to your helmet and shoulders, with just an analogue tacho in front of you and a water-temp gauge tucked away on the left, but the throttle is surprisingly heavy, with the twist-grip operating four separate caibles, one for each carbo There's a choke lever on the left handlebar just under the kill switch, like on every Suzuki two-stroke racer of the period, while the steering damper on the left strange- 58 (Right) The brakes of the era were not what they are today, and definitely not up ta slowing the charging XR23 in proper fashion, adding ta the excitement of the ride. Iy has only three clicks. So, not a lot of choice in settings on something you badly need to work properly on a bike like this, which likes to reach for the stars. Which it does, but only if you get hard on the throttle around 8000 rpm, where there's a sudden hit of horsepower that will have the front wheel eagerly aviating around your ears if you're not careful. But use 10,500 rpm exiting a tum, and you'll light up the rear tire in a way that's an everyday occurrence for today's GP stars but which seems cruel and abusive punishment for the humble-treaded Avon classic race tire fitted to all of Wilson's bikes. Short-shifting the bike made it appear less brutal in its power delivery and easier to ride without sacrificing anything in the way of acceleration, simply because I was balancing grip with grunt and surfing the torque curve from 6000 rpm upward. In fact, the Suzuki would drive from as improbably low as 3000 revs quite strongly, only to hit a flat spot around 5500 rpm, when I suppose it came on the pipe. However, it soon cleared to give a clean buildup of power before things suddenly started happening a lot faster, once the needle on the tacho hit the eight-grand mark. The trick was to avoid leaning the XR23B over too far on those relatively narrow tires; look at period photos of Sheene on the bike, and you'll see he's hardly hanging off it at all, even when it was fitted with the earlier, more manageable exhausts. just trail-brake deep into a comer - almost an inevitability with the weak response of those typically ineffective-period japanese steel discs and their not very grippy two-pot calipers - get the Suzuki turned, and fire it out, keeping it as upright as possible so as to use as much of the fat part of the skinny tire as you can. Then you'll revel in the phenomenal acceleration and marvel over how well the Suzuki hooks up, especially considering the humble nature of the rubber. As I was running in the rebuilt motor, it seemed to have a rather stiff one-up left-foot gear change (in contrast to Sheene's trade- JULY 6,2005 • CYCLE NEWS mark right-foot change), with which it was completely impossible to find neutral, even by hand at rest or rolling gently along with the clutch in, hunting for it with my foot. Clutch action is nice, though: Getting the XR23B off the mark is dead easy, until it comes to coping with the mega-wheelies you get in each of the bottom four gears, just like with one of today's MotoGP bikes, except they have electronic engine-management systems incorporating traction control. The big hit of power that arrives at 8000 revs certainly narrows your horizon, but changing up at 10,500 revs still leaves you in the heavy metal sector of the rev range. However, there's useful overrev, so holding a gear to save a pair of changes, like between the final hairpin at Misano and the chicane leading onto the pit straight, shows that the Suzuki doesn't fall off the pipe once you get past the 10,800-rpm peak-power mark, when according to the Racing Restorations dynojet there's 125 bhp at the back wheel on this bike, just the same as when Hennen used to race it. It still keeps pulling to nearly 12,000 revs if you want to save a change or, ahem, are too busy struggling to keep it pointed more or less in the right direction. I discovered the best bet was to use the bottom two gears to get the Suzuki moving out of slow turns, short-shifting at around 10,000 rpm to third, then riding the torque curve and rewing it out to around I 1,500 rpm, which it was happy to pull in the upper gears while delivering a really vivid performance by the standards of the era. Hold on tight!! However, although the XR23B's 125-bhp output is pretty smali potatoes by today's standards, it's not only mega-powerful by those of a quarter-century ago, but it's also delivered in such an explosive manner that the bike actually seems more powerful than it really is. Face it: This is the power output of an average 600 Supersport contender today, it's just that it seems a whole lot more because of that big hit of acceleration around 8000 revs. Though the rear Avon gave enough grip to let me explore the Suzuki's performance to the point that I could feel it starting to walk beneath me at Misano, just backing off the throttle a tad allowed it to recover without sacrificing much in the way of acceleration and straight-line performance. The quite soft Hagon shock fitted at the rear instead of the unobtainium Golden Shocks (come on, Suzuki, you must have a pair sitting on the shelf in Hamamatsu that you could donate to complete the authenticity of the restoration of this sole surviving XR23B in current use!) meant the bike squatted down a good bit at the rear under hard acceleration, which only compounded its eagerness to lift the front wheel in almost any gear, sending the flapping front wheel into an incipient wobble that the surprisingly goodhandling chassis sorted out forgivingly. This isn't an unstable bike, in spite of its short wheelbase, and it steers and handles quite acceptably for a bike of this era with so much power on tap. Really, the only major disappointment on the Super-Suzuki were the brakes, which each time I rode the bike faded badly in hard use and were never very effective to begin with, either. They weren't at all confidenceinspiring fitted to a bike with this much performance - though using the ventilated rear disc hard did help, except it was really awkward to do so because of those weirdly shaped exhausts. There was a surprising amount of engine braking, though - every little bit helps when the lever's coming back to the handlebar! Thanks to Wilson and Everett, one of the rarest and least-known japanese factory racers - the first stepped-cylinder squarefour Suzuki of the kind which went on to win two World Championships in 500cc form in 1981 and '82 - has been preserved in completely original, track-worthy condition, ready to frighten and impress those fortunate to ride it with its impressive power and scintillating acceleration. eN