Back to the Total Motorcycle Big Book of Concept Bikes

Click photos to enlarge.
They make great desktop images.

1993 Over OV-15A
1993 Over OV-15A

– 1993 Over OV-15A

1993 Over OV-15A

The Over OV-15A was a runing prototype, based on the Yamaha TDM850. The design is made by Over Racing Japan.



Start with a motor that Yamaha could have turned into an impressive sports bike, but instead installed in the sales-bomb TDM850. Add top-quality suspension bits, and garnish with carbon fiber. Transport to your local race track, and cook. That’s the essence of the OV-15A.

The powerhouse motor is filled with enough go-fast parts to make a factory team stand up and take notice. Assorted goodies inside the 870cc Genesis-style 5-valve parallel twin — such as a pair of 12.8:1 Arias pistons with a 2.0 millimeter overbore and titanium connecting rods — work together to pump out 115 hp at 8500 rpm. Route that power through a YZF750 six-speed transmission, wrap the whole thing in aerodynamic carbon-fiber bodywork, add a ram-air carbon-fiber air-box, and with the right gearing, it’s good for a top speed of 270 kph (just shy of 170 mph). More light weight goodies, like a carbon fiber sub-frame and tachometer bracket, allow this horsepower heavyweight to weigh in at just 165 kg (360 lbs).

The running gear is just as impressive as the motor. GP-width wheels from Marchesini, front and rear, mate to grab-a-handful-and-you’ll-loop six-piston Nissin calipers on huge rotors. The trick single-sided swingarm is an Over fabrication, and the fully-adjustable rear shock is from a Japanese suspension group called Quantum. The big oval canister on the Over-made exhaust pipe brings the noise down almost to streetbike levels. It was strange to watch this bike just run away from the field during the AHRMA races while at the same time it was the quietest bike in the race.

When the Over team raced these bikes a week before, the temperature was about 30 degrees cooler, such is the way the weather changes in the high desert. As a result, the bikes were jetted far too rich for the 100-plus degree temperatures we had on this day. The bikes would cough and sputter until they got to the upper third of the rev range then clear up and pull like a 14 year old school boy. It meant that high corner speed was crucial to getting the motor to run well on the way out. Fortunately corner speed comes naturally to these bikes, and the OV-15A was the easiest of the three bikes to go fast on.

Push starting the bike was a lesson in itself — it wouldn’t start unless the throttle was opened at least an eighth of a turn, then when it fired, it just jumped away from the guy pushing it. All the bikes have racing shift patterns — meaning first gear was one up from neutral, the rest down — consequently the first few laps were an exercise in concentration. Every gear shift took about 2.0 seconds as we mentally checked, rechecked and checked again that we were shifting the right direction — we certainly didn’t want to wreck a hand-built, ultra-expensive bike on the first lap, or any lap for that matter. Shifting soon became second nature, though, and the corner speeds went up as the lap times came down.

Even with the rich jetting, the bike would pull hard from 7000rpm all the way to its 9500rpm red-line. The low clip-ons and high seat made cornering a breeze. The easy way through Willow’s Turn Five, a late-apex left that starts downhill and off-camber, was to rest your right elbow on the gas tank to take weight off the bars, plant a knee-skid hard into the asphalt, gas it up and get the rear end to come around and point the bike uphill for the blind, cresting right Turn Six. Get it right, and the reward is a killer drive into wide open Turn Eight. The awesome power throws the bike down the quarter-mile long front straight, and fast laps are ridiculously easy.

– Credit to Mike Franklin, Road Test Editor for the review.

Over Racing
5-14-25 Sumiyoshi
Suzuka City, Mei-Ken
(059) 379-0037
Fax: (059) 378-4253