In the world of motorcycle drag racing nothing is bigger than the NHRA (National Hot Rod Association) Pro Stock motorcycle class. I say that because it’s the only two-wheeled class that runs in conjunction with Top fuel, Funny car and Pro Stock car in the premier league of National USA drag racing; three to four days of qualifying and often 100,000 plus crowds, not to mention huge TV audiences, attract massive sponsorship deals, and so it should. Just look at these intimidating monsters that cover the quarter mile in a few seconds. Well actually USA pinnacle drag racing is now shorter after a fatal crash in 2008 when Scott Kalitta crashed his Funny car, which can be found on YouTube if you want to be shocked. So, to try to reduce speeds, NHRA brought the distance down from 1,320 feet (402m), to 1,000 feet (305m). But, as usual, in racing the top speeds have caught up.
If you’re wondering how fast, as you should, a top-end Pro Stock motorcycle will cover the 1,000 feet in around, or below, 6.8 seconds with terminal speeds of 200mph (320km/h). Also they reach 200km/h in less than four seconds, and a 0-100km/h time of less than one second, with all bikes using only a 10-inch wide rear drag slick tyre! Let’s not forget that a Pro Stock motorcycle has no forced induction (turbo or supercharged) and no nitrous oxide injection is allowed either, they’re all normally aspirated engines in different forms, well only two to be precise.
This class is so tight that well over 40 entries will compete for only16 places in the elimination sages, bit like a world cup with eliminations leading to semi-finals leading to a big finale. I said ‘tight’ because in the last event 6.83 seconds qualified first and 6.94 was 14th, which all leads to the reaction times off the lights to win, where these guys are the best. And ladies too as they can compete on equal terms with the men and indeed Angelle Sampay has won the world tile before. World title, huh…only in America, where every sport has its ‘own’ world title, if you know what I mean?
Now on to the bikes. Apparently they have to resemble a ‘street bike’ from a distance, hence the bodywork but the two engines are either a massive V-twin or not so massive in-line four cylinder. Class rules state the V-twin can be 160 cubic-inch (2.6 litres), but it has to have only two-valve cylinder heads and push rod camshaft activation, also with fuel injection allowed. On the other side is the Suzuki based engine (what else?), which can go to 107 cubic-inch (1,750cc), with a two-valve GS based head and use of carbs only. To also level the field the V-twin can weight no more than 620 pounds (282kg), and the four-cylinder 515 pounds (234kg). Obviously to try to offset the ridiculous torque the big twin makes off the line, but it does make for the closest racing you’ve ever come across. Sometimes lead weights are added to the bike to keep these parameters equal on all counts.
Interestingly the Suzuki based engine still uses modified GS1150 EF crankcases from the eighties but with a hyper expensive CNC billet two- valve cylinder head and predictably hefty clutch and gearbox. Still a testament to how strong those Suzuki engines were and still are. I’ve seen claimed horsepower from a 1640cc engine at 320hp, so being racing figures it will probably be more.
However in the Harley-Davidson and Buell camp it’s a different story and then some. In fact the only connection with the two names mentioned are the brand name stickers on the bikes bodywork, and they’re, err…V-twins. S&S racing division makes the huge engines for the Buell bikes, all 2.6 litres of them. Entirely made from billet components and claiming 360hp plus, who knows what the torque figures must be, and you can even buy just the S&S engine for $42,500 if you fancy transplanting one into your scooter but just listen to these figures folks. 5 –inch piston size or 130mm across, no compression figures but think of at least 18:1, billet rocker arms and push rods made from Superman’s legs that allow this ridiculous engine to rev to 10,500rpm! The camshafts have at least a one-inch lift (26mm) and the valve springs are rated with a return pressure of over 1,400kg, or the same weight as a small family car, amazing components or what? Obviously many ‘secrets’ are hidden in those billet barrels as well, which have cast iron liners.
As you can see from the images here ‘Harley-Davidson’, built by Vance & Hines, are the team to beat with three riders, Andrew Hines, Chip Ellis and Eddie Krawiec who is last year’s Championship holder, leading the way. Steve Tonglet is close behind on the Suzuki machine and many more are close as well.
With one round to go, of 16, at Pomona in California, it’s going to be close and, by the time you read this, it will all have been decided and the NHRA 2018 Pro Stock motorcycle Champion named. So please visit www.nhra.com for all the final class results and even more information, well worth a look. Also check out the many videos of these bikes on YouTube, you’ll be highly impressed believe me!