The Brute

The "Brute" Harley was normally ridden by Jim Hunter.  It was owned by Bud Hood and C B Clausen.  In unstreamlined form, it was the fastest fuel drag race motorcycle in 1952.  In 1958, they ran 172mph on Avenue 5 in Pomona with the Pomona Police acting as spotters and helping make it safe - the road was a narrow 2-lane asphalt road in the middle of orange groves.  In 1954, they put the Brute motor (about 165hp) in the Cooper streamliner after cutting suitable holes in the side of the body for the carbs to stick out  John Fox (the owner) wouldn't let them replace the Norton tranny, so they tried one run and John managed to get it going on almost one cylinder (it loaded up real bad, since I think he started off in 4th gear).  Back in the pits, they lifted the top off and we all gathered round to look.  I asked what the pieces of metal in the bottom of the pan were.  It turned out they were the remains of the transmission.  The engine shook several hundred rivets in the beautiful aluminum body loose.  I just wish I had taken some pictures.

Source: Landracing.com

Clausen and Hood's bike, called the Brute and better known for it's drag racing successes, bettered 168 MPH at the 1952 Bonneville runs. It has never utilised a blower and in 1952 was not enclosed. In 1953 a plastic shell was built for it and in that form it made a one-way run of 170.13 MPH, but at that speed began an alarming wobbleand the machine all but started to fly. Fortunately, no disaster occurred and it was decide d to develop a new aerodynamic shape for future attempts. The engine burns a rather strong mixture of nitromethane and methanol which is reputed to permitthe development of fabilous horsepower - enough to drive the missile at over 200 MPH at an engine speed of less than 5000 RPM. Clausen claims that he has ample power, and the only problem is to keep the fron wheel on the ground.

In order to accomplish that end, a new frame and shell have been designed and built in Clausen's modest cycle shop in South gate, California. In the Mark II Brute, the rider Bobby Kelton, will sit ahead of the engine on a seat mounted on the lower frame member, just a few inches off the ground. The wheelbase has been lengthened by approximately two feet, and the new plastic shell is of torpedo shape and has a rudder at the rear. Except for the tail, the machine will be less than three feet high.

Clausen, Hood and Kelton must be enthusiasts of the first order. For all their trouble, expense and risk, the only reward can be self-satisfaction. Because of the size of the engine, no official American recognition can be granted in the event of attempts being successful. In C.B. Clausen's words: Ï just want to build the worlds fastest motorcycle".

Reprinted from E.M.A.P./Classic Bike copyright Dec 23, 1954

Source: From Walneck's Classic Cycle Trader Aug 2003

Faster than a Jet

For the firsdt time since 1907 a motorcycle leads the world in Speed - This time it's acceleration
Cycle Magazine April 1952 - Text and Photos by Ernie Reshovsky

There used to be a time, when to hit 100 mph was considered a milestone by the average cycle owner. As a matter of fact, I remember the day (and it was not too many years ago) when a friend of mine, an ardent cycle fan, proudly announced that he had done an indicated 85 mph on his Indian and for weeks talked
of nothing else. All of his friends were duly impressed, considering that in those days we could barely squeeze 70 mph’ out of our automobiles and thought we were really going places.

Lately the “milestones” came hard and fast: A Harley-Davidson hit better than 136 mph; then the U.S. record was shattered by a British Vincent at 156.58 and finally the specially constructed highly streamlined NSU raised the world’s cycle record to better than 180 mph in Germany. All these speeds were attained with
flying starts, and the records were set by specially constructed machines usually with ample help from 5 respective factories.
In the last few years a new kind of cycle construction has been developed which has no factory backing and which keeps the sport strictly in the hands of a relatively small group of experts—owners—riders who have made tremendous progress.

I am referring to the enthusiasts who are pioneering those bombs on two wheels that have such a terrific acceleration potential over short distances: The drag jobs.

Although built for a definite purpose, i.e., to wind up to phenomenal speeds from a standing start over a quarter mile, this type of construction is strictly an. American creation. “Dragging” had its origin in the Southern California area, but by now has become nationwide.

The drag jobs are usually built by those expert at getting every last 1/2 hp applied to the rear wheel with as little loss as possible.
For some unknown reason these machines consistently out-perform all types of four wheel vehicles such as Hot Rods, Lakesters, etc., when it comes to acceleration. Although the top speeds attained by four wheelers are higher than those of cycles, the acceleration of the latter is better than their four wheel brothers-in-arms at drag races. The four wheelers logically have twice as much traction, but the record still stands.

One of the cases in point is a cycle which has created quite a stir lately whenever it appeared at one of the Southern California drag strips. “The Brute,” as the machine is affectionately called, has recently set the drag record at Santa Ana drag races at 132.81 mph over a distance of a quarter mile from a standing start, an excellent achievement indeed.

The cycle is jointly owned by Bud Hood and C. B. Clausen, with Mr. Clausen doing most of the construction work at his shop (C. B. Cycle Sales) in Los Angeles in his “spare time.” The fuse was lit back in 1948, when Bud Hood acquired a 1941 Harley Davidson 74 ohv. The bike was bought in parts, and Bud rashly decided -"to find out how fast it could go.” Once bitten by the bug, Bud found out—and as he put it, “we are still finding out,” which gives rise to speculation that top speed has not yet been reached.

Since 1948 the machine has gone through many states of development, some most unorthodox. All engineering work was done by co-owner Clausen, and it was first decided to make it a road machine to run on gasoline. After relatively few changes, which consisted mostly in alteration of carburetion and the addition of a C B. cam, the Harley ported and polished and at thar time running on one rebuilt Harley-Davidson carburetor, reached the speed of 122.44 mph. This was done in 1949 at Rosamond dry lakes, running on gasoline. This was hot time in its day, but human nature being what it is, Bud and C. B. hungered for more.

It was ‘decided to make the machine into a drag job with all stops pulled, reach the maximum in acceleration. Bud Hood now admits chat at the time he did not know what they were getting into by making the decision. Very little was kncwn about such construction, and most of the engineerin, roblems had to be worked out by the old trial and error method. Obstacles were encountered which no one had dreamed of; however, they finallywere conquered after a loc of work and a great deal of thinking.

An example of the problems encountered were the cylinders. The original cast iron barrels blew under the great pressures setup, and C. B. finally decided that the only solution to the problem would be to make cylinders out of steel. He obtained two solid chunks of seven-inch steel, turned the fins on a lathe and shaped the fins by hand. The cylinders were bored on the lathe and finally hand honed to a finish. The base thickness was increased to 3/4 inch for additional strength agaiast the Vrinch base on «he stock cylinders. In their final state the cylinders are just about able to withstand any pressure, weigh just twice as much as stock cast iron ones, i.e., 16 lbs. vs. 8 lbs. Nevertheless, C. B. felt that since had to be reached somewhere, the additional strength of the steel is worth the weight.

At one time C. B. was toying with the idea of aluminum alloy barrels with steel sleeves, but two years later, having had two pattern makers work on the project and having spent a considerable sum of money, the idea was discarded as "just a beautiful dream".

The carburetors—two 1 5/8 inch Rileys, activated by a single connecting rod—were made to order as was the all-important cam.
The latter was modified by Clausen who has done a great deal of research into cam designing and now manufactures "C.B. Modified cam" for all comers.

The replacement of thie generator by a magneto presented another one of those little things that have to be carefully thought out.
After the Harley-Davidson Wico magneto arrived, it was noticed that improvised chain driving it rubbed against the case, thus the case had to be ground down just enough to allow for clearance without impairing it strength. The outlet for the distributor, was plugged and sprocket and magneto installed in place of the generator.

Then came the problem of transmission, a proverbial weak point in many high performance jobs. Clausen employed a Harley Davidson three-speed transmission, using only second for starting and a high, the ratio of which is 3.5:1, Only a couple of Sundays ago, high gave out during an early trip and the starting gear alone was used for a couple more runs to establish the day's track record of 115.28 - pretty fine for a “low gear” in any man’s language.

Valves are of unequal size, intake valves being two inches in diameter while the exhaust valves remain fundamentally stock - 1 5/8 inches across. Nevertheless, the bevel on the exhaust valves had to be carefully altered by turning on a lathe, to prevent the intake valves from colliding with them on the overlap. This alone gives an indication of the fine limits to which parts must be machined.

Harley-Davidson (1940-1947 type) stock heads were used - machined and welded to allow for dual carburetion.

To overcome flywheel spread at high rpm, case rollers are Timken tapered bearings in the lower end, requiring no end clearance.

Then came’ the problem of pistons. Stock buckets were out of the question, and it was decided to have them manufactured to specifications. They had to be designed correctly to make full use of the power, yet strong enough to withstand great heats and tremendously increased pressures of 13:1 without caving in.

But cave in they did periodically, and the design often was changed. In the present state, pistons are made of aluminum
and are domed. Each piston has three soft iron rings, each one a scraper. The decision to use three rings was in abhorrence of oil leakage. It was the smaller of two evils to have the aditional drag of the third ring rather than the leakage of oil past two rings. This holds doubly true since very cold plugs (Champion LA. 14) are used.

The eternal question of fuel composition is one which cannot be compounded into a hard-and-fase rule. As it happens, the combination which so far gave the best performance was 20 per cent nitromenthane to 80 per cent alcohol. Depending on humidity, temperature, etc., the fuel has contained anywhere from'15 to 26 per cent Nitro on other days. Having taken all factors into consideration, C. B. corfipounds the fuel just before the run to the appropriate proportions. The fuel is pressure fed by a hand air pump from tank to carburetors.

To many, one of the remarkable things about “The is the fact that so far the cycle has never been dynamometer-tested. The absence of such highly accurate tests does show how far performance can be pushed by proper application of plain brain power and engineering know-how.

A great deal of experimenting has gone into tire selection. The front wheel carries a 400-18 Firestone, while the rear tire is a 500-16. During the experiments it was established - and this will come as a great surprise to many - that the best acceleration over dry asphalt is achieved by a slick rear tire, with a gum rubber base which sticks to the ground when hot. Now there will be many selfstyled experts, who can prove by
slide rules and theory that a slick tire is bound to have less traction than anything else, but C.B. stands firm on past performance figures using other tires. Thus a slick rear it's for “The Brute.”

Riding this powerful wild cat is something that has to be experienced to be believed, says Louis J. Castro, 28, who has guided “The Brute™ from its"conception. His position while on the record-breaking runs is pretty well flat on top of the tank, peering
through the upper portion of his goggles He keeps his head way down, with his crash helmet offering as little wind resistance as possible. His legs bend sharply with his feet resting on the foot pegs which are about in line of the rear axle, where brake and clutch controls are located.

Watching the start of a run is one of the most exciting things imaginable. After having been pulled by another cycle, "The Brute" roars impatiently at che starting line, quivering while it warms up. C. B. usually leans over it, making last minute adjustments while strong smelling exhaust gases pour out the stacks, smarting the eyes of spectators.

Finally, as the starter’s flag whips, Louis guns the motor, opens the throttle fully and only then lets out the clutch with expected results: There is a screech of tire against asphalt - at the same time a black cloud ofrubber goes up and mixes with smell of exhaust gases - and by the time the spectators have time to look took up, there is the back view of “The Brute™ halfway down the quarter mile track, with the motor noise fading away in the distance.

Then in a hush of subdued excitement the timer's voice rings out over the P.A. system:
“One hundred thirty-two point eighty-one miles.” Bud Hood (the owner) turns toward C. B. Clausen and, with faces beaming they pump each other's hand, set off for amongst compliments of their friends. About that time Louis Castro, having returned via the back stretch, rolls into the pits with that glassy expression on his face.

Toward evening the bike is being loaded carefully into the pick-up and taken back to its stall in C. B.'s shop, where he will take it all apart (as he always does after every 40 miles or after every record run) carefully checking for failures and wear.

And next Sunday they will be out again on one of the strips, trying to better their own mark and throwing out the gauntlet to all comers, two-wheeled or four-wheeled, to improve the time over the quarter mile. The offer still stands, and all comers are taken on.
If some of our hot rod friends do beter with their additional traction (and this is where the theorists can prove their point) “The Brute" will take them on any time. “And,” say the owners, “we'll show them down the runway.”

Cycle Magazine June 1952

Puff that chest out fella, go ahead and strut around a bit. American cyclists have good reason to rise and shine on several counts, one of which your editor had the personal satisfaction of witnessing a few days ago. Remember that story, “Faster Than a Jet” that appeared in the April mag?
Well, the basis for that far reaching tag line was taken from facts supplied by those wizards of the slide rule, the aircraft engineers, who revealed that it would take one of the fastest modern jets from 10 to 11 seconds to squirt that first quarter mile.

Well, we were on a deadline at the time (is there any other time?) and so their word was good enough, but knowing the far reaching talents and keen interest of CYCLE's readers, your staff decided that we'd better have an ace up our sleeve when some of those extra potent letters started pouring in.
Your magazine's public relations man did the impossible, made arrangements at Lockheed to stage a drag race between—yep, you guessed it—a jet fighter plane and a motorcycle.

C. B. Clausen and Bud Hood, builders of “The Brute,” world’s fastest drag bike, nearly lost control when they heard of the proposition and together with their eager little jockey, Louie Castro, were first on the hangar apron the morning of the duel. The contest was to be held on two parallel runways, but it was only after Louie had returned from a trip to the end of his strip that the sad news was known: his runway had a kink in the forward end of the strip that would make it impossible to negotiate at speed.

Nevertheless, the Brute was given a trial run over the available straightaway and it was then that the problem solved itself. The jet test pilots shook their heads, “we're no match for that baby.” So in lieu of a jet, a faster accelerating P51, prop-driven fighter was warmed up and brought out to the line, since it required less take-off space and was able to start from the bend in the runway.

Believe me it was a tense moment as the two stood shivering and revving as they waited for the sign to go. So there could be
no possible controversy, the plane was purposely allowed to accelerate an instant before the Brute was gunned and, to us at the other end, it looked as though the day was lost for the first hundred yards. Then it happened, the Brute began to grab traction. Although the bike was only geared for a quarter mile, at the end of a half mile it was a good four plane lengths ahead of the already airborne P 51 — what a thrill, what a day for the bike boys! In this age of speed in the air we still hold our own!

Source: Walneck's Classic Cycle Trader, Mar 1997

Brute versus the Jet

Christened ‘The Brute,’ the bike gained a reputation around California for destroying everything that pulled alongside. To put ‘The Brute’ to the test, in 1952, ‘Cycle Magazine’ arranged the impossible. ‘The Brute’ would race a USAF jet.

The summer of ’52 saw Louie Castro onboard the Knucklehead lining up on a parallel runway to a Lockheed T33 Shooting Star. With ‘The Brute’s’ un-silenced roar almost drowning out the whine of the jet, the contest was over before it began.

Bare Knuckle Ride

The fire-breathing Knucklehead only had to take a practice run, and the flyboys threw in the towel. Pilot Irvine Prait, saw the bike run, knew his jet could cover the quarter mile in around 10.5 seconds, and famously said, “we’re no match for that baby.”

The Air Force wasn’t ready to call it a day, though, and they wheeled out a 1,650 horsepower P-51 Mustang. Although the Rolls-Royce Merlin engine was propeller-driven, it was faster down the runway than the jet. ‘The Brute’ had its work cut out.

The race was extended to a half-mile, and the fighter was allowed to start first. As everyone expected, the Mustang charged ahead, leaving ‘The Brute’ in its rearview mirror.

Halfway down the runway and with the Mustang now airborne, the slick back tire on ‘The Brute’ finally gained traction. The overhead-valve Knuckle roared down the runway thundering past the plane. It crossed the finish line four plane lengths ahead! According to Cycle Magazine, ‘The Brute’s’ fastest quarter mile was timed at 9.4 seconds.

Source: Old.News.Club

THE BRUTE: THE FIRST STROKER KNUCKLEHEAD

 Panhead_Jim

The story of how the first Harley-Davidson Knucklehead stroker motor was built reminds me of those old Reese’s Peanut Butter Cup commercials from the 80’s. Random events would always cause a chocolate bar to land in a jar of peanut butter, resulting in an unexpected and delicious flavor combination. Just like the commercials, random events brought together all the parts to build the first Knucklehead stroker motor and it only took the right person to see how they all went together.

In case your not sure what a "stroker" motor is, let me get you up to speed.  When you are building a “high performance” Harley-Davidson engine, or any engine for that matter, there are two standard methods for increasing displacement and in turn increasing horsepower and torque. The first is to bore out the cylinders and fit larger pistons. This approach is commonly used to convert an 883 Sportster into a 1200 Sportster and produces good results at a relatively low cost. For those that really want to hot rod their engine and are willing to invest a bit more time and money, lengthening the stroke is a second option for adding more displacement. “Stroking” an engine is a much more extensive modification requiring complete disassembly of the cases and the installation of different flywheels and connecting rods.

That may seem like a lot of trouble to go through, but there are some key advantages to stroking vs boring. The longer stroke increases leverage on the pistons which results in more torque. Also, a stroked motor will typically produce more horsepower than an engine of the same displacement with a larger bore. So if you converted your 74” motor to an 80” motor by stroking, you would have more horsepower than if you bored your 74” cylinders to reach the same 80”displacement.

That all sounds pretty good, but with any performance modification there are always some downsides. The extra stroke length means that your piston has to travel a longer distance when moving up and down inside the cylinder. This distance has to be covered in the same amount of time as in a stock engine, so your piston speed goes up as does the amount of wear and tear on your engine. The increased piston speed can also be problematic if you want to run at high RPMs for sustained periods. This can lead to catastrophic engine failures when the piston reaches a velocity at which it can no longer maintain its structural integrity. Still the stroker motor has proved to be a viable powerplant and for applications like street riding and drag racing, it has been a popular modification since the first stroker motor was built in the late 1940’s.

According to a first-hand account from Gil Armas, who helped build the motor, it all came together one afternoon in his shop. Gil was tearing down the 80” engine from his Big Twin Flathead when his buddy C.B. Clausen happened to stop by. While Gil was taking apart the Flathead, C.B. was on the other side of the shop looking at Gil’s Knucklehead engine which was laying in pieces on the bench. After eyeing the parts for a while, C.B. went over to Gil and picked up the flywheels from the Flathead engine. A quick check with a ruler confirmed that they would fit inside the Knucklehead cases, so C.B. started putting the Knucklehead back together using the larger Flathead components.

Everything was going fine until he fitted the engine with 61” cylinders. The increased stroke of the Flathead flywheels caused the pistons to stick out past the top of the cylinders. Unphased, C.B. grabbed a set of 74” cylinders and everything lined up perfectly. The piston skirts had to be modified slightly to clear the flywheels and with that the stroker motor was born.

Looking back, this seems like it would be pretty obvious to most motor builders, but you have to keep in mind that the Flathead and Knucklehead engines are two very different motors. Flatheads use a side valve configuration which houses the valves inside the cylinder casting, beside and parallel with the piston. The Knucklehead uses overhead valves mounted in the cylinder head, just like most modern motorcycles. These large differences must have been what kept others from attempting this parts swap.
Now here is where the story really gets interesting, fast forward a few years to the early 1950’s. C.B. Clausen and his stroker motor had been making a name for themselves on the drag strip and the salt flats. C.B. nicknamed the machine “The Brute” and pilot Louis Castro raced it in a variety of configurations including a full streamliner. Cycle Magazine got wind of this machine and decided it would be a great promotional stunt to drag race The Brute against a US Air Force Lockheed T-33 jet.

The race was held in Los Angeles, CA on April 12, 1952. Taxiing across the runway, the jet was able to complete a ¼ mile run in 11 seconds. The Brute made the same pass, but beat the jet, running the ¼ mile in 9.4 seconds and reaching a speed of 132.81 MPH. Not to be outdone, the Air Force brought out a P-51 Mustang. This time the plane was airborne, but The Brute was able to beat the Mustang by 4 plane lengths on a ½ mile course.

The success of the stroker motor led to the production of custom made stroker flywheels, which you can still buy today. Now you can easily stroke almost any Harley-Davidson engine, from a 1915 J to a 1999 Evolution using stroker flywheels kits available from Truett & Osborne. Something to consider the next time you have to rebuild your old Harley. Who wouldn’t want to have a Harley that was faster than a jet…

Source: Riding Vintage.com

This is set of 4 original 4 x 5" black and white photos that are a 8 x 10" full page sheet of film that were taken by Eric Rickman for Trend Inc. (publishers of Cycle magazine, Hot Rod, and Motor Trend) in 1952 at the Bonneville Salt Flats in Utah.

The first photo is the full page film sheet. The top left photo is Louie Castro doing a full body lever while flying down the salt on the Bud Hood-C.B. Clausen 84 cu.in. OHV Harley-Davidson that clocked 168.77 mph on a one-way run. Actually this is somewhat of a world-wide accomplishment since bike was both un-blown and un-covered (no supercharger or streamliner shell). So, while this bike called "The Brute" went 168.77 mph, there was no open class for motorcycles over 74 cu.in., so it was also un-classified, and even though it went this fast, it couldn't get its name in the record books. Before the speed trials was over with, the engine seized on "The Brute". From the November 1952 issue of Cycle magazine page 10 "Bonneville under fire" article: With the best meals in Wendover coming out of the trunk of jovial Bud Hood's Cadillac, it was a sad day when the Brute stuck up and put an end to it all. Savvy little Bobby Kelton was sitting in for regular rider Louie Castro at the time and the clocks were registering better than 160 mph when the big overloaded Harley engine locked tight, throwing the bike into giant broadslides from first one side then the other. With skill and confidence rare to his years, Kelton hit the clutch, uncoupling the powerful twin, and coasted the white behemoth to a standstill.

The photo at top right is Bobby Kelton on his regular ride "The Brute Jr.", riding past cars waiting in line to make a run. This smaller version of the Brute, called the Brute Jr., was still too large a displacement size to fit into the 74 cu. in. or smaller classifications (I'm guessing it was a 80 cu. in.) and even though it averaged 150.75 mph for the two way run, it couldn't set a record as there was no open or unlimited displacement classification in 1952. I'm not real accurate when it comes to identifying American motorcycles, but I think the guy riding next to Kelton is on a Harley-Davidson EL. He may be Bud Hood, or C.B. Clausen, or anyone else for that matter, but he does look familiar to me. It appears the Special roadster is throwing salt or just salted the front of the Ford F1 pickup truck sitting behind it, particularly on the windshield. The presumed Harley EL appears to have a chrome gas tank and looks very stylish and sophisticated, not like a salt flats racer. This photo has the red x and a red framed box inside it, like it should have been printed in the November 1952 issue of Cycle magazine, but it was not published.

The bottom left photo is Louie Castro on the Brute going through the traps.

The bottom right photo was cropped on all 4 sides and is the exact same photo as the one that was published at the bottom left corner of page 10 in the November 1952 issue of Cycle magazine in the article "Bonneville under fire". It is Louie Castro smiling and posing for the camera on the Clausen-Hood Harley-Davidson known as "The Brute".