It would be my guess the reason the mechanical device that disengages and engages the crankshaft rotation to a wheel, eventually transmitting the crankshaft rotation to the wheel, causing it to rotate, had to be called something that would reflect its mechanical function. Hence the word clutch is used.

All clutches are devices that clutch together two objects, as on a motorcycle the crankshaft and the rear wheel, or would it be the clutching together of the clutch plates? As a torque converter which has no clutch plates performs the function of transmitting crankshaft rotation to wheel rotation, the later would be correct.

Since the invention of the internal combustion engine man has strived to increase the efficiency of a given amount of swept volume. As the given amount of swept volume increased, clutches had to keep up with the increase of power. The problem that the racer has in most cases concerning clutches, is that he more often than not is working with a factory produced machine where the manufacture designed that machine with a given horsepower and designed a clutch which would transmit that horsepower. I have found that in most cases the factories run into the same problem that the racer does, many times increasing the hp, leaving the clutch unattended, and eventually either overpowering the clutch or eliminating any fudge factor the original design might have had.

This ordeal has plagued Black Lightning from the start. In 1996 the liner went to the salt with a modified V-2 clutch, more plates and heavier springs. This clutch was grossly inadequate for the hp produced. Cost $1,200. In 1997 a total rethink on the clutch was in order. In 1997 my brain was not very flexible, so naturally my thinking was, It's a motorcycle, a very powerful one, for sure, but nevertheless a motorcycle." So a motorcycle clutch it had to be. The most powerful motorcycles on the planet in 1997 were the blown fuel inline "4's" making their way across the other big pond from Japan, and with a little American ingenuity managed huge horsepower readings in the neighborhood of 4 to 5 hundred. As there were literally hundreds of these bikes in the U.S. doing battle every weekend, the clutch problems had to have been pretty well solved, (I thought.) The four factors involved which make it work are: friction coefficient between the plates. This has to do with the lining used on the clutch and the lining's ability to withstand heat. Second would be the combined area on the mating surfaces of all clutch plates. Third would be the amount of pressure applied to the mating surfaces. No problems so far, but number four had to be addressed and that was clutch speed. As the inline 4's were turning around 12,000 rpm, and the gear ratio between the clutch and the crankshaft was around 1.5 to one, this meant that the clutch was turning around 8,000 rpm on the inline 4's.

What am I talking about here? Clutch speed. The clutches location in most motorcycles is between the engine's crankshaft and the transmission. The torque developed is transmitted to the rear wheel through the transmission. Now that we have the power train in mind, on with the importance of clutch speed.

When the liner is running at 6,500 rpm the clutch will be turning a little over 4,000 rpm, as the ratio is 1.555 to one. A transmission is nothing more than a torque multiplier or reducer, transmitting a given amount of torque, depending upon the efficiency of the swept volume at a given rpm. For simplicity let's say that the streamliner at 6,500 rpm develops 1 foot pounds of torque each time it fires. That torque is transmitted to a clutch spinning at 4,000 rpm. The transmission in low gear transmits the torque to the rear wheel. In low gear the torque or turning force has a factor in proportion to the gear ratios in the transmission. In other words the rear wheel is easier to turn due to the number of times the engine is firing in relation to the rpm of the rear wheel.

The clutch speed is a constant with engine rpm, as they are mechanically married together. The engine and clutch speed is not a constant with a rear wheel when a transmission is employed in the drive train.

When the transmission is shifted into a taller gear, the rear wheel receives fewer torque impulses from the engines firing, thereby making it harder on those torque impulses to do their thing. Hence, harder on everything between those impulses and the rear wheel, where lies a clutch which remains constant. If the clutch speed were to increase in proportion to rear wheel speed, the clutch would not be affected by additional torque loads. The torque load on the clutch would remain the same, so therefore the closer you can get the clutch speed to the engine rpm and the rear wheel speed, the better off you are. It takes less clutch and she won't get as hot!

So knowing that the clutch speed on the 4's was greater than the clutch speed I would be able to obtain, due to the physical make-up of the Vincent cavity where the new clutch would find a home. Off to a little town in Virginia I went, where a company called A.R.T. was located. I presented them with my problem of clutch speed and they took the job on to design a one off clutch that would do the job.

After two months of waiting the clutch was finished and I exchanged $3,400.00 in greenbacks for the clutch. Of course it came with a spare set of clutch plates. (Quite a bargain, don't you think?)

The clutch was used at the Bonneville runs in 1997, where it held during it's only run, ending in a crash. Stu Rodgers of the U.K. was the rider that year.

In 1998 the clutch held, pulling a deployed parachute to 151 mph on it's third run. (We discovered that a deployed parachute was not the way to go fast.) Don Angel from San Diego earned his 150 mph license on the run, but unfortunately the liner went on it's side again.

The clutch was used in 2001 during Vibrac's dyno test of my 1998 engines. The clutch held the 254 hp reading of the dyno.

The clutch held again in 2002 when Black Lightning (now the Vibrac streamliner) was under lease to Robert Watson and Dan Smith. After Dan asked me, I tuned the liner for what turned out to be the last run of the Vibrac attempt, and with Dave Campos riding the liner, that run was able to reach a speed of 191 mph.

In November of 2002 I began the job which took the next two years, redesigning and building a completely new streamliner in my shop in Wichita, Kansas. I contacted Terry Prince and asked if he would consider building stroker crankshafts for Black Lightning. He agreed. John MacDougall, a former member of the Vibrac team, wanted to help. John has rebuilt many Vincent engines and I had heard only good things as to his expertise. As he had Vincent tooling in his machine shop, I asked him to coordinate the building of the strokers and the cylinder muffs with Terry Prince and to procure cylinder liners from L.A. Sleeve. John worked approximately three months in Canada on the Black Lightning project, making the drive side main shafts for the strokers, assembling and balancing, and machining the cylinder muffs to accept the oversize liners. All the while I was working in Kansas, U.S.A. on the Muncie three speed transmission, blower drives, manifolds, remote starter, prepping and boring the cases to accept the larger sleeves, etc. After this was completed I drove to Vancouver and John and I worked for about 25 days assembling the motors.

The new streamliner made her debut at Speed Week, August 2004, reaching a clocked speed of 153 mph. At the 2 1/4 mile marker, the fastest 2 1/4 mile speed ever recorded among any of the past five Vincent streamliners. We were limited to 150 mph on the run by the scrutineers.

The now 3000cc power plant developed major torque which the clutch refused to accept for the first time.