Royal Enfield diesel motorcycles in the U.S.

Tom Judd and Aaron Scott will build you a Royal Enfield diesel motorcycle.

Converting Royal Enfield motorcycles to diesel power is a popular notion — diesel Royal Enfields have even been produced commercially, although not in the U.S. Now Coloradans Tom Judd and Aaron Scott want to do it for you.

They describe themselves as "two environmentally-conscious motorcycle enthusiasts trying to bring something to market that the major manufacturers just have not provided." The environmentally friendly motorcycles they make will be able to transport people using diesel fuel or carbon-neutral fuels like vegetable oils or biodiesel.

Their motorcycles will be multi-fuel, simple, reliable and serviceable AND will get 130-plus miles per gallon, they promise.

They call their operation MotorEarth to emphasize the mission.

MotorEarth diesel motorcycle.

To make it happen they've started an IndieGoGo campaign to raise $25,000. The money will enable them to buy the engines, transmissions, body parts, paint, rims and tires to complete the 11 chassis currently in Denver. Those who contribute get a variety of "perks," from a toolbox sticker to the opportunity to buy the first motorcycles at introductory prices.

But the dream doesn't end there.

"If there is room for it in the funding, we will put research into moving full production to India and making a completely new, high-efficiency, light, diesel motorcycle for the world market," they write.

That future motorcycle might not look much like a Royal Enfield. But, for now, Royal Enfields were an obvious choice for conversion. They "are known for their simplicity. They are rugged, field tested, easy to maintain and repair," the Indiegogo proposal notes.

"All Steel, All Mechanical, All Analog!"

It's a great slogan. The single-cylinder diesel motor promises 13-horsepower, which they say will take you to 100 kph. A prototype continuously variable transmission maximizes the available power.

Check MotorEarth's website for more information on the diesel conversion.

Tom is a designer, engineer and machinist and Aaron has experience sourcing and manufacturing products in India and the U.S., according to the proposal.

One last promise they make: "We will get it done."

Meet Tom and Aaron and see a prototype run in the video:

Around the world on a Royal Enfield diesel motorcycle

Let's go for a test ride on a diesel powered Royal Enfield Bullet.

Harry Lyon-Smith went around the world on a Royal Enfield Bullet powered by vegetable oil and diesel fuel. He called the motorcycle "Batty," not because of the sound it made but because he conceived of it in Battersea and he knew the idea of going around the world on vegetable oil sounded a bit batty.

Even so, you won't believe the noise the motorcycles makes in a recent YouTube video of a test ride on Batty.

It's a bit unfair, since both Lyon-Smith and test rider RJ comment that the diesel motor isn't really so loud. Apparently the helmet cam microphone emphasized the diesel clatter.

Nevermind. Going 'round the world on this thing is one impressive feat. Starting in May, 2011, it took just over two years for Lyon-Smith and Batty to complete the journey. Their story is charmingly told in Lyon-Smith's travelogue style blog, Vegibike Around the World.

The 1971 Royal Enfield Bullet was converted to bio-diesel power by Price Part Motorcycles in the UK.

The 50,000-mile world tour took Batty to the highest road in the world in the Himalayas. She ran all the way to Nepal on 70 per cent vegetable oil.

Batty loaded at the start of her journey.

But this proved in part her undoing, as the bike went through four engines; only the first burned vegetable oil well. Lyon-Smith eventually ran on diesel only, accepting that modern diesels, optimized for low emissions, run best on petroleum.

With 435cc, RJ reports that Batty is capable of 130-plus miles per gallon. But it makes only 10 horsepower.

At one point, in Mexico, Lyon Smith writes:

"Much to the amusement of others, the only way Batty could make it up the final hill into the town was by offloading all my luggage boxes etc (about 50 kg) into a passing rickshaw."

He sent away for a smaller front sprocket!

Let's go for a ride:

Diesel powered Royal Enfield runs on biodiesel fuel

Royal Enfield runs on petroleum diesel or biodiesel fuel.

Few Royal Enfields attract more cult interest than the rare diesel powered Taurus models. In even more demand recently are those that will run on biodiesel fuel.

There is a clean looking Royal Enfield powered by a Greaves diesel motor for sale on CraigsList in Albuquerque, N.M. The seller, Ray, says that he runs it on B100 (pure biodiesel fuel).

Diesel motor looks natural in Royal Enfield.

Ray is selling because "like all things British and manufactured in India, she needs some TLC" — more than he wants to provide. He believes the motor needs a ring job. He provided details on the Royal Enfield Yahoo message board:

"I found this bike at a biodiesel conference in Golden, Col., and I envisioned making it my clean, green, commuting machine. I've never owned a motorcycle before, and it wasn't until after I made the purchase... that I discovered that this bike needs some work to run at its best... I'm moving, I'm old, and I don't need another project.

"It has the Taurus Greaves engine, and I'm confident that once the rings are removed, they can be matched by any competent machine shop.

"I'm not trying to cheat anyone and that's why you can make me a reasonable offer and come away with a super-cool retro bike like no other."

Ray says that he paid $3,940 for the motorcycle in 2006. He prefers to be contacted through his CraigsList ad.

Royal Enfield diesel and trailer a nice combo

The Royal Enfield diesel motorcycle shown on this blog recently must have struck Helmut Forsbach as a bit of a coincidence. He emailed me these pictures of his own 1999 diesel-powered Royal Enfield.

Helmut even has a PAV 40 single-wheeled trailer, like the Sommer motorcycle Dirk, from Germany, showed us, below.

Helmut is in Germany, too, but his motorcycle is the original Taurus diesel powered model from India, which featured a 325cc Greaves motor. Seven horsepower!

Helmut is pictured next to his motorcycle. At "68 years old (young)," he looks like a serious traveler. That cute little trailer must come in handy!

The PAV trailers were made in Czechoslovakia during the 1960s and '70s for Jawa motorcycles. Here in the U.S. we can get the Inder trailers, inspired by the PAV but made in India. They are available from Classic Motorworks.

Royal Enfield diesel looks handsome

A diesel powered Royal Enfield Bullet might be the answer to the question no one asked:

"Hey! Isn't there any way to make this thing any slower, heavier, noiser and smellier?"

But there is no denying the beauty of the Sommer 462 Diesel with Pav 41 trailer shown here. Dirk, from Germany, shared these pictures of his motorcycle. What is it?

The Sommer turns out to be the typically German effort to thoroughly engineer perfection into machinery.

Imports of Royal Enfield's own 325cc diesel into Germany in the 1990s served as the starting point. "Too dirty" and "too slow," it nonetheless inspired Jochen Sommer to look for a better alternative. He found it in the single-cylinder four-stroke Hatz 1B40 diesel engine with fuel injection and an electric starter.

Cost is 7,500 Euro ($11,000, but that includes the ghastly 19 percent tax). You can get Sommer diesel Royal Enfields in black or eye catching ruby red or signal yellow. Other colors are 300 more Euros (and presumably more tax, so don't ask).
The Hatz firm is happy to provide information on operating on biodiesel fuel or vegetable oil, if you're interested.

Fuel consumption? I'm not that adept at converting liters consumed per kilometer to miles-per-French fry. More important to me was converting the figure for "maximum speed." Prepare yourself: 62 miles per hour.

If you wanted to go faster you wouldn't be reading a Royal Enfield blog anyway.

The Sommer web site would rather share Jochen's "philosophy." Most Royal Enfield owners and riders will find themselves agreeing with much of it:

"A motorcycle embodies for me the best way to travel in 'freedom'... Suspension, wheels and engine combine to form an aesthetic whole, a motorcycle. My personal preference is the simple motorcycle. Lightweight and compact, these should have all parts easily accessible... with a high-torque motor, free of electronics and made entirely from metal.

"A Hatz diesel engine is a universal motor, which mainly serves the industrial and marine markets. This sector requires absolute robustness and simplicity... Stringent emission levels can be met, the diesel injector is long lasting and high compression and low speed combine for great economy."

And, then, there is the sound, always critical on a Royal Enfield:

"Your ears and your senses will be satisfied. Low speed with low-frequency level is perceived as pleasant and always subjectively quieter than a high-frequency noise. The driver of a diesel is pleased to take note that the trip was pleasant and relaxing.

"Come and join us for a test drive. I'm sure it will be for you a special experience."

But not in the United States. I wrote to Jochen Sommer to ask if his machines are available in the U.S. and got this response:

"Dear David,

"No they are not. We did not homologate it for the US.

"Best Regards

"Jochen"

A shame.

Royal Enfield road trip proves his point

Geoffrey Baker rode his homemade bio-diesel powered Royal Enfield motorcycle from Mexico to Canada. The freelance writer and web designer in Tucson, Ariz. planned the trip "to promote awareness of fuel efficiency."

He didn't quite make his goal of doing the trip on only 10 gallons of fuel, but he came close enough at the finish line Aug. 30 to dismiss any argument that it was a stunning accomplishment. I will let him tell you his final miles per gallon average.

The full story of his road trip is on his blog. It's an adventure story, as parts rattle off the Royal Enfield and the rains come down. But Baker also describes a pleasant trip, with stops along the way to see the sights. His eight-day journey was no mindless blitz from border line to border line.

Along the way he repeatedly had to explain Royal Enfield motorcycles, his elaborately modified diesel machine, and his mission. It all makes for a fun read, even if you'd rather burn gasoline in your own motorcycle.

One thing that surprised me: Baker got away with going slow. Royal Enfield motorcycles are slow in general, diesels are slower still, and he wanted to go deliberately slow to save fuel. And yet he enjoyed the ride and didn't feel "run over" by traffic.

His trip inspired me to plan one, although I am not up to the elaborate preparation and thought he put into his ride.

Royal Enfields inspire gentle jokes

Royal Enfield motorcycles and British motorcycles in general always inspire good natured jokes about mechanical reliability and quirks. Robert Fransworth recently alerted the Bullet-Mania Yahoo message group to a particularly odd Royal Enfield for sale on eBay in the United Kingdom.

It was the seller's gentle humor about his motorcycle that caught my eye:

"Royal Enfield diesel, 406cc Greaves engine Taurus model, 1991. Diesel engined Bullets aren't for everyone. It will cruise at very low revs all day at 45 mph. At this speed it's very happy just knocking along; being a diesel it runs very cool. This, combined with the low engine speeds, make for a very comfortable relaxing progress.

"Open the throttle and it will pull up to 60 mph but at this speed the vibration will make your hands go numb, bits fall off and the speedo cracks (it's on its third)... Bike located near Baldock in Hertfordshire."

The motorcycle is in "nice oily rag condition," the seller further advises, and it will run on vegetable oil or regular diesel fuel. You can just about smell it from here!

This motorcycle is not for me, but I love the attitude and honesty of the description. Who would you rather buy from? Someone who claims his Royal Enfield Bullet is fast, smooth and reliable as taxes, or someone who cheerfully welcomes you to the fraternity of riders interested in other qualities?