2008 Four Stroke Worlds Preview & The Wild Bikes That Made It Possible

On Apr 15, 2008

FOUR STROKE WORLD CHAMPIONSHIPS: A LOOK BACK

By: Zapÿ

Funny thing this motocrossÿworld. Forÿall of its early decades the sport ofÿmotocross was simply a four stroke sport. Of course that all started to change in 1965 when Suzuki sent two mechanics and a rider to Europe to contest the GP’s with both a single and twin cylinder 250 race bike. The idea ofÿ a twin was based Joel Robert’s success aboard the twin cylinder CZ 360 the year previous. It wasn’t until 1967 when the factory showed up with its first official “works bike”, the RH-67. With theÿR&Dÿhelp of veteran Swede Ole Petersen, Suzuki kept developing the bike until it was good enough to win over the Belgium duo of Joel Robdert and Roger DeCoster. In 1968 Suzuki introduced the first ever Japanese production two stroke MX bike, the twin port TM250 of which only 100 were made available. In short order Yamaha, Kawasaki and finally Honda joined the MX fray and effectively put an end to the four stroke’s earlier dominance.

The Four StrokeÿWorld Championships were the brainchild of Knobby Shop International founder, Alan Greenwood. The first event was held in 1977 at Carlsbad Raceway. In 1988 theWhite Bros. stepped in to promote the event and it was under their care that the race enjoyed it’s greatest success for the next decade. This weekend at Glen the Four StrokeÿWorld Championships return to Glen Helen with title sponsorship now provided by MTA. Sure, the obvious question – when & where willÿthe Two Stroke World Championships be held? Time willÿtell.ÿ

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21st Annual MTA World Four-Stroke Championship

With just a few short days away until the 21st Annual MTA 4 Stroke World Championships (the sponsor has has changed from the White Bros.) the riders are lining up for a shot at over $9000 in purse money.

MTA has taken over where White Brothers let off to back the one of motocross history’s best known events. With the fact that there is no AMA National Prequel race this year (because Glen Helen is the opening round of the Outdoor Nationals) this will be the first and last test for the Pros to get a shot at the Glen Helen National layout (including the new Saddleback twin peaks).

There are always a few surprises in what riders show up unannounced, but here is a quick list of who is expected so far:

ÿÿÿ Team Suzuki rider Mike Alessi.
ÿÿÿ Team Bad Boy Racing’s Jeff Alessi.
ÿÿÿ Former WORCS’s Champion Ricky Dietrich.ÿ
ÿÿÿ Zip-Ty Yamaha rider Bobby Garrison.
ÿÿÿ Former Pro Circuit Rider Bobby Bonds.ÿÿ
ÿÿÿ KTM rider Justin Soule.
ÿÿÿ Big Gun’s Matty Dowell.

There is a $2000 pro purse for the 250 Pros on Saturday and a $7000 prop purse for the Open Pros on Sunday (any size four-stroke can race in Sunday’s [pro race). There is also a $1500 Quad Pro Purse on Sunday. There are all the Sportsman classes both days. Each day is a stand-alone event.

Gates open at 6:00 am and its $20.00 for adults for the weekend or $10.00 a day. Children 6 to 12 are $5.00 per day. Amateur Class entries are $45.00 post and $40.00 pre. 250 Pro Entries are $50.00 and Open Pro are $85.00. Camping is available at the track. For more info, Click Here.

Four Stroke Worlds: The Bikes That Came Beforeÿ

The first Japanese four stroke to make a dent in the racing world was the Yamaha TT-500 based bike designed by Sten Lundin. A version of this bike was campaigned by Bengt Aberg who used it to win the 1979ÿLuxembourgÿ500 GP… at the time popular wisdom had it that Bengt’s win would be the last MX victory by a four stroke ever! Lars Larsson imported the frame kits from Torsten Hallman and they sold for $745 with the complete bike selling for just over $3000.ÿ

Years after the dual sport SL models of the 70’s were finally discarded, any rider with high hopes of riding a Honda thumper had to rely on the heavy, off-road intended XR series of bikes.

The ADB Avenger was designed by Horst Leitnerÿin 1994 and was originally called the PBH-Scott for sale in England.ÿUsing a Rotax 604 motorÿand White Power suspension, the PBH was later sold to American Dirt Bike and sold as the Avenger with full body work.

Sticking a four stroke motor into an existing frame that wasÿoriginally used for a two-stroke motor was a clever way to save weight andÿtry and to find someÿhelpful MX handling traits.

For some reason, the San Diego area of Southern California was a haven for four stroke race bikes. The Horsepower Factory bike was one such local effort by Malcolm McCassey Sr. This bike used a Honda motor with a Uni-Trak replica rear end the popular (back then) integrated rear fender & number plate.ÿ

The Brown Bros. took the concept of “pit bike” to unforeseen levels with their series of super exotic race/play bikes. From aluminum perimeter frame kits to dozens of suspension and engine mods, BBR Motosportsd has it all. For more info, Click Here.

Husqvarna was the first “modern” dirt bike brand to re-introduce four stroke MX platforms. The 500TC was a mid-80’s production bike. Yes, the swingarm does look awfully spindly.ÿ

The 500cc BSA B-50 MX debuted in 1974 and was available with Triumph badging as well.ÿThough heavily modified to race by BSA riders like Chuck Minert and Dave Aldana, the B-50 still paled in race worthy comparison to its 1966 predecessor, the BSA Victor GP.

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If there was one thing the early four stroke World Championship events gave rise to it was the hybrid/mongrel bikes. No, they weren’t all pretty to look at, but they did have lots of character.ÿ

Alan Greenwood is the man credited with forging the So. Cal four stroke renaissance. Not only was he the man behind the Four Stroke World Championships, but he also marketed his own thumper race bike. The KSIÿ410 used a Honda motor, twin Fox air shocks & Simons forks. Available as a frame kit for $1170 (with shocks) and the fork sold for $350.

Long before people started stuffing four stoke motors into the frames designedÿto hold aÿtwo-stroke motor, English frame builder Rickman was well ahead of the game.

There never seemed to be any lack of imagination in terms of what some people thought it would take to build the ultimate four stroke race bike. Akront rims, Maico forks, Preston Petty Mudder front fender and a motor that probably weighed as much as the entire rest of the bike.

Here’s a classic race bikeÿ – the Clews Competition Machine, also known as the CCM. The British built bike did the best job of flying the four stroke flag into the two-stroke dominated decade of the 70’s.ÿ
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