Motorcycles with Car Engines

By Leroy B. Vaughn

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image1I was doing a little research a few days ago and I came across a copy of a Popular Mechanics magazine cover from June 1935.

The price of the magazine was 25 cents and the cover had an illustration of a racer riding a big motorcycle with the words 300 miles per hour on the exhaust pipe. The motorcycle depicted on the cover was a modified Henderson X model that had been lengthened and strengthened to accommodate a 1934 Plymouth PF in line flat head six cylinder engine and transmission.

The engine was modified and produced 125 horsepower at 4,500 RPM after it came back from a speed shop.

The bike was 11 feet long and weighed 1,500 lbs. The steering was mounted behind the center point of the engine and the rider was able to keep the machine on its wheels with skid plates mounted on both sides that also acted as brakes to slow the machine down.

Fred Luther was a motorcycle racer from California. As an employee of the Chrysler Corporation, he was able to talk Chrysler executives into providing the engine and transmission for his racer. Seven years after the first Plymouth car came off the assembly line, the Plymouth powered motorcycle was on the salt flats at Bonneville.

image2Fred Luther had taken the bike to Bonneville in an attempt to set a world speed record and collect a cash prize of $10,000. He was hoping to take the machine to 300 miles per hour. He hit 140 mph in the first leg and on the return leg a connecting rod broke at 180 mph. He was in second gear at that time.

He called it quits after coasting the bike back to the pits. Luther always believed that the bike could do 300 mph, but he was not going to try again. The cash prize of $10,000 turned out to be a hoax, and he never found another rider willing to take the big bike up to 300 miles per hour.

At the time of Fred Luther’s run in 1935, no automobile had been able to reach 300 miles per hour.

image3In 2003, sixty eight years after the motorcycle with the Plymouth engine ran at Bonneville, Chrysler engineers designed a concept motorcycle called the Tomahawk.

The Tomahawk weighed about the same as Fred Luther’s Plymouth powered machine but had a lot more horsepower.

Chrysler mounted a 500 horsepower Dodge Viper V-10 engine onto a frame supported by four twenty inch wheels.

Chrysler says the Tomahawk can reach 60 mph in 2.5 seconds and has a theoretical speed of about 400 miles per hour. The Tomahawk has never been driven at over 100 miles per hour. The four wheels are necessary to keep the 8 ½ foot long machine upright.

The Tomahawk is classified as a car by the National Highway Traffic Administration. A motorcycle can have no more than 3 wheels on the ground during normal operation.

image5Chrysler sold nine replicas of the Tomahawk for a reported price of $555,000 each as collector’s item. I thought I was finished with this article until I sat back and started remembering another crazy machine that I had seen pictures of and read a motorcycle magazine story about in the 1970’s. I was originally going to call this article “Motorcycles and Mopar engines” and then I decided to add this machine to the story. I had a hobby garage in back of the house I was renting and I had two projects that I was working on, or planned to work on.

Someone had given me a Harley-Davidson Moto Morini that needed work and I had a chopped Triumph frame sitting against a wall that I really wanted to build, when I wasn’t out riding my Norton Commando.

Above the Triumph frame was a big poster of a machine called the ROADDOG. I could no longer use the Mopar title for my article because the ROADDOG had a Chevrolet engine.

The ROADDOG was built by an electronic engineer named William Gelbke. Mr. Gelbke was called “Wild Bill” by his road buddies. He claimed to have ridden his machine 20,000 miles in the first year after he built it. 20,000 miles might not seem to be a lot of miles on today’s cruisers, but the ROADDOG was nothing like any other motorcycle on the road, possibly ever.

RoadDogThe ROADDOG was powered by a four cylinder, 152 cubic inch Chevy 11 “Iron Duke” engine with a Powerglide transmission. The machine was shaft driven and was stopped with disc brakes.

The ROADDOG was too big for a side or kickstand. Four hydraulic rams were used to hold the machine upright when parked. Each ram was deployed individually.

The machine was 17 feet long and weighed 3,280 lbs.

Wild Bill was seen cruising the highways at 90 plus miles per hour, and his friends have told people that they went with Wild Bill and the ROADDOG on trips from his home in Wisconsin to Texas and Oklahoma, for a beer or steak dinner.

In 1979, Wild Bill was killed in a domestic dispute and the ROADDOG disappeared for fifteen years.

A motorcycle collector searched for the ROADDOG for about six years and located it after writing an article in his magazine.

I have been fascinated with odd motor vehicles since my teenage years in southern California in the early 1960’s. This was the era of Von Dutch, George Barris and Ed “Big Daddy” Roth.

Among the many model cars I built before owning my own cars, hot rods and motorcycles was a model of Mickey Thompsons Challenger speedster with its four Pontiac engines.

And now, as I head for the refrigerator for a cold beer, I can’t get that song “Hot Rod Lincoln” out of my head.

2 thoughts on “Motorcycles with Car Engines”

  1. Leroy B. Vaughn

    The list is short because magazines have a word count. The machines you mentioned would make a good story for a book.

  2. I’m surprised your list is so short. I have seen motorcycles powered by: VW flat four, Corvair flat six, Alpha Romeo V6, Smart Car diesel, Ford flat head V8, and more. The most common, Boss Hoss with Chevy V8 engines, is still in production.

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