WW. The BSO and the Kreidler Special

Posted July 27, 2015

In keeping with the theme started two weeks ago with the Garbage Can Special (see the page “WY. The Garbage Can Special”), this week’s story describes two other garage-built racing motor cycles. Again I apologize for the quality of the images, but the original photos are long lost. These are scans of half-tone images from the yellowed pages of the old Lap Times.

This first article is a modified version of one that appeared in the August 1976 issue of the Lap Times.

The BSO Racer co-authored by Ken Mullins

By 1975 Vance Breese was already a veteran racer. Vance had a habit of racing, um, unusual motorcycles. He once told a story about racing a Bultaco Metralla, crashing into the desert at high speed at Willow Springs. He slid under a pickup truck while the Metralla flew over the truck, or maybe it was the other way around. In 1975 Vance had won the 500 G.P. class riding a BSA Victor 441 (perhaps bored out to 500cc), and had earned the number 5 in the AFM. In 1976 Vance was defending his title in the 500cc G.P. class with a BSO.

What’s a BSO? A reasonable question. You start with a BSA Victor 441. The 441 was called a street-scrambler back in the day, what we now call a dual-purpose bike. Vance took out the 441cc single-cylinder motor, modified the frame a bit, and put in a 498cc ESO motor. The ESO is also a 4-stroke single, but intended for a speedway bike. Speedway bikes don’t have gears, and the ESO motor had no gearbox, so a Norton 5-speed gearbox was added. None of these things were ever meant to work together but on Vance’s bike they all looked natural. The BSO used a Norton fuel tank and sometimes a half-fairing, both painted gloss black.

bsoVance Breese at speed at Sears Point on the BSO. Photo by Mush Emmons.

Ceriani forks and a big 4-leading-shoe drum brake were fitted on the front end. The tires were treaded racing tires, a Dunlop front and a Michelin rear. An exhaust pipe and megaphone were fabricated by Williams Pipes in Redwood City, and Selby Motors helped some. The bike was making somewhere near 50 horsepower at the rear wheel. Vance had considered getting a newer 4-valve head from ESO/Jawa to help increase horsepower.

Some competitors had taken one of the Yamaha TZ750 cylinder pairs and installed them on a TZ350, making it essentially a TZ350 with a 375cc motor. The oversize motor moved the bike from the 350cc class up to the 500cc class. Since the original TZ350 was rated at 60 horsepower, you can see what Vance was up against. Vance used the light weight and good handling of the BSO, along with his own considerable riding skills, to overcome this disadvantage. He successfully defended his title, being the 500 G.P. Class Champion again in 1976.

The following article appeared in the July 1977 issue of the Lap Times. I simply copied the article, so when it says “this year” in means “1977.”
Jewel’s Gem

Last year the 50cc GP class was dominated by a neat little Italian bike. The Moto Villa was fast (for a 50cc bike), won a lot, and took its rider to the class championship.

This year things are different. A small yellow bike has shown up and has been winning with regularity. What’s more amazing is that the bike is virtually homemade, a rarity these days of superb factory-built racers. Intrigued by any work-shop built bike, I talked to the owner/builder/rider, Jewel Hendricks. Jewel is a machinist and it’s generally known in the Southern California community that he’s a good one.

The bike is powered by a Dutch-built Kreidler engine. You have to understand about Kreidler – they don’t sell race bikes, they sell motors. Once you talk them into selling you one (Jewel has been at it since 1974) what you do with it is your own business. You get the complete engine in a box, the motor with Kroeber ignition, a silenced expansion chamber exhaust, water pump and radiator, and a handful of counter-shaft sprockets.

JewelMotorA close up view of the motor. The cylinder and head are nearly as big as the crankcase. Inside the cases is a 5-speed gearbox and clutch. Just above and to the left of the motor is the electric water pump.

The engine is a real beauty, a very compact water-cooled single with a 5-speed gearbox. The cylinder is nearly horizontal and is very large for a 50cc bike, giving lots of cooling fluid surrounding the cylinder and head. The motor is nearly square with a 40mm bore and 39.7mm stroke. The bore is plated with “Nickasil,” a nickel-silicon alloy that’s tougher than chrome. Porting is pretty straight-forward with a disk-valved intake. The carb, a 28mm Amal on Jewel’s bike, hangs off the left side of the crankcase.

The engine is rated at a healthy 16 hp at 15,500 rpm. The bike is capable of speeds up to 100 mph, depending on wind and the slickness of the fairing. Remember, this is a production engine; the factory has bikes racing in Europe that have been clocked at 126 mph!

JewelsCrankAndCyl(Left) Everything is tiny inside the engine. The 40mm (about 1.5 inch) piston has a single Dykes-style compression ring. The crank wheels are only three inches in diameter. Also shown are the inlet valve disk and one fiber and one metal clutch plate. (Right) The bore is inside a substantial cylinder with lots of room for cooling fluid.

So it’s a neat little motor, but you can’t win races with just a fast engine. To get through tech inspection you are going to need a frame, wheels, fuel tank, and other accessories. The engine’s shape lends itself to a backbone-style frame, so that’s what Jewel designed and built. The main tube is 1.75 inches in diameter, of .049 inch thick steel. It runs from the top of the steering head straight to the swing-arm pivot tube. There’s a sub-frame that triangulates the steering head then extends rearward to hold the seat and upper shock mounts. There’s a small tube on each side running from the shock mounts to the swing-arm pivot to support the read of the sub-frame and provide a place to hand foot pegs and controls.

JewelsGemThis image shows the homemade frame with the large single backbone tube. Also visible are the tubes that form the sub-frame, and the way the carb is mounted on a disk-valve 2-stroke.

At the front Jewel has fitted Ceriani forks stolen from a small dirt bike that he shortened 3 inches and re-valved. The shocks are S&W units that were intended for a minibike that have also been reworked.

One advantage of building you own frame is you can make it fit, and Jewel’s 5’ 9” frame slips right into the bike. It has a longish wheelbase at 51” – by comparison a TA125 Yamaha has a 48” wheelbase. After studying frame theory and asking a lot of questions Jewel selected a 27 degree steering head angle.

“I found that it’s hard to go wrong with an angle of 27 degrees,” he says. He also selected a trail value that, by theory, would give a dead neutral handling. Jewel is pretty happy with the results, but admits that if he did it over again he’d give it one more degree of rake to increase straight-line stability at speed.

The bike’s brakes are single disks at both ends with Grimeca master cylinder and calipers. Jewel made his own disks of aluminum then had them plasma-coated by Harry Hunt. Jewel considered leaving them uncoated but thought better of it.

“They’ll work fine, but if you get one little pebble caught in the brakes the disks are ruined.” The brakes stop the bike through tiny Dunlop racing tires – a 2.00×18 front and a 2.50×18 rear, laced up to “smaller than WM-0” rims. To mount the front Grimeca caliper tabs were welding to one of the fork sliders, then the slider was straightened to remove the distortion cause by the welding heat.

JewelAtSpeedJewel at speed at Ontario or perhaps Riverside raceway. He tucks in nicely since he built the frame to fit someone his size.

The whole bike works very well. In six races this year Jewel has 4 firsts and 2 second place finishes. The bike has given no real problems, although the clutch plates need frequent replacement and it’s hard to keep the temperature up in the short club races.

The bike is as fast as is claimed. At Riverside recently a rider of a 125 Production bike, who almost never gets passed by a 50cc GP bike, had Jewel pass her coming out of the fast turn 9 (the AFM lightweight race includes both classes). She tucked in behind hoping to get a draft up the front straight when she heard the little yellow bike shift into 5th and leave her rapidly behind. The Kreidler-powered bike was running over 85 mph and still had a gear to go.

3 thoughts on “WW. The BSO and the Kreidler Special

  1. Another 70’s garage built bike was Kevin Bracken’s Ducati Darmah, cobbled together from two crashed bikes in the Wood’s Motor Shop garage in Glendale. This was only the beginning for the amazing changes the engine and frame were to experience over the years. The bike was run in AFM, ARRA and AMA Open Production, Superbike and BOTT races over a number of years starting in the late ’70s.

  2. I don’t really understand why folks make comments about these stories on Facebook instead of in this box designed exactly for that purpose. Here’s a reply that went to me on Facebook instead of here.

    Steve Elmore wrote: Cool, but a couple issues: While Kreidlers are still very popular in Holland, they are German-, not Dutch-built, unless this is some special project. Also, these popular Kreidlers were, indeed, complete bikes. The “Florette” model comes to mind, but there were others. But, yeah, maybe they never sold race-specific bikes.

    Rob Labordus replied: The VanVeen Kreidlers were the competitive ones and they were Dutch-built. I know this because I owned one back then.

  3. Steve is partly right, partly wrong. Kreidler was indeed a German company, set in Stuttgart, on the other side of the big plaza in Unterturkeim, opposite to… the Mercedes-Benz headquarters. Kreidler was an exotic metals company, selling alloys to Mercedes, Porsche and other German car makers. It was also, since the early 1950s, producing mopeds, and in 1957, introduced the 49cc Florett, a 3-speed wonder with “Baroque-Angel” styling, of which engine was the first using a new process developed by Mahle: nickel-silicon cylinder coating and a forged piston. That and a very solid crankshaft bearing meant that these mopeds were close to unbreakable, and could be driven for over 100000 miles with little else than time to time, change the transmission fluid.
    The Florett grew into a 4-speed, 60 mph “mockick” machine that began humbling most 125cc and larger bikes. And the Germans as well as a few Dutch racers began racing them, competing against more exotic Italian machinery from Itom, Benelli, Demm… and soundly humbling them.
    By 1961, there was a European Cup and the Kreidler works team, led by Hans Anscheidt, cleaned up. By that time, the machine had evolved from a piston ported induction to a dual disc-valve, twin-carburetor setup using a 3-speed gearbox relay, effectively offering 12 ratios through combination of a rotary left-hand shifter besides the foot shifter.
    In 1962, the “Cup” became an official class in the FIM World Championship and there, the fortunes of Kreidler began to change. First, the new, Ernst Degner-designed Suzuki GP bikes, driven by Degner, Anderson and a pair of Japanese racers, overwhelmed both the Kreidlers and the new 4-stroke Hondas. In fact the only faster bikes were the Spanish 8-speed Derbi, also derived from a moped engine, but they did not come out of their borders, content to humiliate both the Germans and Japanese at the Spanish GP in Montjuic Park.
    From 1962 through 1968, Suzuki and Honda, first with single cylinder engines, then twins, shared the world titles and victories, with Anscheidt collected the crumbs with more evolved Kreidler engines and chassis. In 1966, Kreidler, which had seen moped sales flounder in Germany, pulled out of racing and sold their equipment to their very active Dutch importer, Henk Van Veen. Anscheidt signed with Suzuki and won three titles on the trot, two as a works driver, the last as a privateer, as once the FIM, afraid of the mounting competition from the Japanese factories, banned the multi-cylinder miniature monsters they were preparing for 1968 (3-cylinder engines of 49cc!), Suzuki left him with a pair of bikes and a box of spare parts. He used the 50cc to good effect but was never successful with the 125cc. Then, the exotic Japanese 50cc twin was no longer legal, and Anscheidt retired.
    The road was open at last, for the Dutch Kreidlers, now entirely built in Holland, to win the championship, but the Spaniards were also prepared: while Van Veen built new engines using water cooling, 6-speed inline gearboxes and more sophisticated chassis and aerodynamics, Derbi now participated to the World Championship races and… won it after a fierce battle with the Dutch Kreidlers. It took until 1971 for the Van Veen machines to at last, win the title, and repeat in 1973. Kreidler will win 6 more titles with their ever-evolving machines, that now developed nearly 22 HP, from a humble 3 HP moped engine designed 25 years before.
    So it is necessary to clearly understand that while most Kreidler had German underpinnings, there were also Dutch-built Kreidlers, but those did not use any parts from the German engines.

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