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Rupp Centaur History

The History Of The Rupp Centaur

The History of The Rupp Centaur is quite extensive and the history of this machine as told by me is the information I have been told over an 8 year period. If there are is any part of this history that is not true as to what you have been told and can verifiy that information please email me and I will be sure to change it as I am not the know all see all of the Rupp Centaur. Thanks and I hope that this info helps in some way to clarify the many emails I have gotten reguarding this machine.
Click on the Thumnail Pics. to see a larger view of the pic.

Rupp was an American company that was operated out of Mansfield, Ohio and owned by a Mr. Mick Rupp. The company started in early 1970 or 1971. They produced a multitude of machines including Snowmobiles such as the Nitro and Magnum, also Dirt Bikes like the Enduro. They also made a variety of Mini Bikes including the Scrambler, Roadster and the Black Widow. Also Produced was a Go-Kart. And as far as I know some of the first off road ATV's. These would be the Four wheeler named the Go-Jo and the Rupp Rat, which was a 3 wheeler that was only produced in 1974 and very rare to be found today.

The Rupp Centaur was only produced in 1974 and 1975. They were only molded in four colors, Blue, Red, Yellow and White. There were as I have been told four differant body styles made, however I have only seen two. They would be the 1 seater and the 2 seater and have not seen a variation as to how they appear in either of the two years. The bodies were constructed of fiberglass and were very flexible. Over the years though, the flexing created stress cracks. For the most part they can be and the majority of the time will be located on both sides of the rear fenders.

Inside the body, was a two piece plastic instrument panel.

The first piece housed the Speedometer and Tachometer along with Idiot Lights that indicated Right or Left turns, Headlight High Beam and Neutral Indicator for the Transmission. Also was the Engine Choke and Electric Key Ignition. The second piece covered the gear shifter and emergency brake levers. It was also equiped with full leather interior.

There were approximately 1200 produced between the two years in production. In order to find out what year and number your Centaur is you need to locate the Vin number. The Vin number is located on the left side and is stamped on the steering limiter tab. If the first 2 numbers read 47, you own a 1974, if the first two numbers read 57 then you own a 1975. The following numbers after that will tell you what number it is in that year. Such as mine, I own a 1974 and my Vin number reads 470056. this indicates that it is a 1974 (47) and is the 56th made in that year (0056).

There were also 2 differant rear bumpers made for the Centaur and are obviously differant when spotted. Both are made with round metal and were chromed and are in the shape of a long oval. However, one of them has a flat spot in the center for license plate mounting and the other has an indent for the license plate mounting.

This is where the history gets a bit wierd. According to a person who owned and operated a Rupp Dealership in New York that I know, It is said that when the design for the Centaur was created, it was designed to use a VW engine and transaxle. At the time VW was still producing the Super Beetle. After the frame was completed and ready for the VW engine and transaxle, VW came back to Rupp and demanded more money than was originaly agreed upon in the contract. Rupp refused to pay the money and decided to use the company that they were using for there snowmobile motors and mini-bikes and already had a contract with. This company's name was Kholer, which was a Canadian owned company and is still in buisiness today. Rupp revamped the frame design a touch to accept the 2 stroke motor that was being used in there snowmobiles.

Below are the exact Engine Specifations as taken from the Owners Malual.

Model: SK-340-2AS Oil Injected

Type: Two Cylinder, Air Cooled, Two Cycle.

Displacement: 339cc

Compression Ratio: 7.5:1

Carburator: Mikuni 32mm

Oil Pump: Mikuni Dual Output

Ignition Type: Capacitor Discharge Ignition

Alternator Output: 150 watts

Ignition Timing: .090 BTDC

Spark Plug: Champion N-19V

Starter: Electric

Air Cleaner: Paper Filter Fram CA-148PL with Special Seal

After the Motor was chosen, Rupp designed a gear box that would act as the Automatic transmission and would be a belt driven cytrifugal clutch. It was equiped with dual disk hydraulic rear brakes along with a disk brake on the gear box that would serve as a transmission brake or parking brake, since even in the foward gear it could still easily roll. The Brake pedal for rear braking was mounted on the right side of the driver in the front. Behind the gear box was a rectangular 10 gallon gastank.

Together the motor and transmission were very unreliable and the transmissions were renouned for breaking down. The motor wasn't much better, as most people know a 2 stroke motor is not designed for a constant high RPM use. Because these vehicles were designed for on the street use, the motors were conastantly at a high RPM rate which would explain why they broke down and repairs were always needed. This would also explain why most people who own a Rupp Centaur have converted it to VW power. You have almost no problem doing it because the Torsion Bar from a VW Super Beetle slips right into place with little frame modifications needed to be done to the Centaur frame. Also, the body in no way needs any modification. although the use of the trunk in the rear becomes the hood once converted. Which, if what I was told is correct it was designed to be a hood to begin with and was converted to a trunk after the 339cc motor was installed.

Along with the custom designed gear box in the rear, it had an independent rear suspension system. The shocks were mounted at the top and down on a piece that the axles ran through with a bearing in the center of it.

the front end is still one of the simplest around and is somewhat like like a springer front end on a Harley Davidson. The front shocks were adjustable to allow for whatever kind of ride the rider wanted. These front shocks are more like the rear shocks of a motorcycle.

It was also equiped with a 32 spoke 16" wheel with a mechanicle drum brake.

The Handle bar Controls were also quite simple. on the right side is where the front brake lever was lacated along with the Engine Run/Stop Switch and the Twist Throttle. On the left side, the Clutch Lever, Headlight High/Low Beam selector, Left/Right Turn Signal Switch and Horn Button were located.

N.O.S. (new original stock) parts for these machines have become almost non-existant and very hard to find. If you have a stock Centaur and would like to restore it to factory condition, you have a few options. If the motor is siezed or in need of repair you can purchase a newer version of the same motor from Kholer or a variety of other manufacturers that make the same type of motor. They are more dependable now than they were back in the 1970's, but are still 2 stroke motors and every so many hundred hours or miles of operation the motor will need to be torn down for piston and ring replacement. If your front end chrome, luggage rack and rear bumper need to be replaced, re-chroming is an option. the front wheel is more or less a standard 16" 32 spoke dirtbike rim with a drum brake. Many companies such as Honda, Kawasaki and Yamaha made these rims, so you may be able to pick one up. If the speedometer gear has gone bad on the wheel, it was told to me that a moped device will work.

This is about all the info I can think of and hope this helps you out in some way. If you have any questions or comments please send me an email.

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