Diesel motorcycles aren’t a common sight anywhere in the world. Royal Enfield was one of just a few manufacturers to even bother putting one into mass production. Perhaps less-known than the Royal Enfield Diesel or the Hayes Diversified Technologies M1030M1 is the Star Twin Thunder Star 1200 TDI. This motorcycle with a meal of a name combined a Volkswagen Lupo 3L 1.2 liter diesel engine with a sportbike frame. The result is what its creator called the world’s first diesel superbike and maybe, perhaps the only diesel superbike.
Every time I dive into diesel motorcycle history, I end up finding something new. Most recently, I’ve been finding myself disappointed at how expensive the aforementioned HDT M1030M1s are on the private marketplace. Not too long ago, they used to sell in government auctions for rock-bottom prices, now they can cost more than a shiny new Indian FTR. So, I’ve turned to the idea of maybe importing a Royal Enfield Diesel. My search for an Enfield Diesel has uncovered some more diesel motorcycles from history. One was the bewildering Boccardo Aero 97, a diesel motorcycle that caters to people who don’t ride for excitement. That bike is worth something of its own one day but today, we’re going to take a look another diesel oddball.
This is the Star Twin Thunder Star 1200 TDI:
This motorcycle isn’t like the typical diesel machine, if you could call any diesel bike “typical.” The HDT M1030M1 was built to serve a specific purpose. Our military believed in streamlining the fueling process of its vehicles so that there wouldn’t be a need to haul around multiple types of fuel. The M1030M1 is a multi-fuel motorcycle that will run on the same JP-8 that fuels aircraft, negating the need to worry about the quality of gasoline out in the field. On the other hand, motorcycles like the Enfield Diesel, Boccardo Aero 97, and the EVA Track T-800CDI promised long legs thanks to their miserly engines.
The Star Twin Thunder Star 1200 TDI is different. It wasn’t built to go over 500 miles on a single tank like the Track or be a cheap scoot for the people like the Royal Enfield. Instead, this motorcycle was built to prove that diesel could be as good, if not better, than a gasoline engine.
The Skunkworks Behind The Bike
This motorcycle is the work of Dutch motorcycle nut Van der Starre. Starre is the co-founder of Star Twin Motors, a shop specializing in Italian motorcycles. The shop opened in 1979 and it’s not just a place to buy a motorcycle, but it is also a skunkworks for Van der Starre’s projects. Starre says that his shop (he now owns Star Twin Techniek BV) aligns motorcycle wheels and frames, fabricates custom exhausts for a variety of vehicles, and it builds motorcycle parts and full custom bikes. Starre’s shop will seemingly do custom metalwork, bending work, or anything else you might be willing to pay it to do. In fact, Starre’s motto is “Can’t, Doesn’t Exist.”
Clearly, this mantra also applies to his custom motorcycle builds. Starre’s custom work includes the funky Lovel F-20 trike, a custom diesel engine, a chopper, a drag racing motorcycle, and more. Pictures of all of these builds aren’t provided, but just check out the trike:
This machine targeted car drivers. In a blurb on Star Twin Techniek’s website, it says that the cars of today are loaded down with technology like cruise control, stability control, air-conditioning, and other features. The Lovel is supposed to take driving back to its purest form. This trike weighed just 793 pounds and was powered by a 1.0-liter four making 145 HP. Its performance? Apparently, it hit 60 mph in just 3.5 seconds. It rode on an aluminum frame and the body was a composite structure with carbon fiber reinforcements. So, that gives you an idea of the engineering behind these projects.
The Star Twin Motors dealership remains open today and it looks like Star Twin Techniek is still taking custom orders after having moved to a new location in 2020. Van der Starre still runs the show today!
The Star Twin Thunder Star 1200 TDI
This motorcycle was designed to prove something. In a 2005 interview with Gizmag (known as New Atlas today), Starre noted that he had been watching the development of diesel motorcycles and felt that they gave underperforming results. However, automotive diesel engine development had progressed far enough that Starre felt that they could now maybe match or surpass gasoline engines.
At the time, Gizmag pointed out that there were a bunch of concept or prototype motorcycles out there like the Neander 1400 Turbo Diesel, the AVL Boost, the Dieselfighter, and more. Of course, this also came not too long after the discontinuation of the Enfield Diesel and right as the first HDT M1030M1s were going into service.
Back in 2005 when that article published, the production motorcycle with the biggest-displacement engine was the Triumph Rocket III.
We’re talking a beast with a 2.3-liter triple making 140 HP and 147 lb-ft torque. The diesel motorcycle performance concepts and prototypes of the bunch had some things in common: They matched or exceeded the torque of the Triumph with smaller engines. To Starre, the diesel engine was about ready to prove itself to be better than a gasoline engine.
Starre spoke to the Rider’s Digest, giving this reason for building the machine:
“Because I like to stay that nothing is impossible and the modern diesel engines in cars are so good, we believed we could do better than the rest and build a fast, competitive diesel bike.”
As for why he decided to build a diesel superbike? Starre felt that building a machine that could race was the most challenging kind of motorcycle to build, so a perfect showcase for diesel technology.
Starre’s project kicked off in 2001 with help from Jeroen Bernart, who was then attending the HAN University of Applied Sciences. Bernart first designed the motorcycle by modeling it in 3D on a computer. There were a number of challenges presented in making this motorcycle a reality. Apparently Starre had an intern that also worked at Volkswagen and that’s how they were to score the 1.2-liter turbo diesel triple from a Volkswagen Lupo 3L. From there, the team had to do a lot of custom work, from the Rider’s Digest:
The whole engine was modeled in 3D in-house prior to the build. New engine casings where designed and cast to allow for a new custom-made 14-plate dry slipper clutch mated to a 5 speed gear box out of a Yamaha FZR1000.
The massive torque from the engine created a challenge even for the notoriously sturdy FZR gearbox, so an additional output shaft was fitted to increase torque demultiplication. Despite the lower revving nature of the diesel, the gearbox actually works at a similar RPM as it did in its donor bike.
A new turbo was fitted, and the increase in boost pressure to 2.5bar required stronger intake valve springs as the standard valves where being pushed open! Fuel injectors were also replaced for bigger units running a higher pressure.
The stock Lupo 3L engine was rated at 60 HP and 103 lb-ft torque, already pretty decent for a motorcycle. Initially, Starre raised output to 70 HP and 118 lb-ft torque before ironing the engine out to 125 HP and 185 lb-ft torque in its final form.
Along with a custom case, the engine got a lightweight flywheel, saw its balance shaft deleted and gained a Mitsubishi turbo. The completed engine weighs 275 pounds while the whole motorcycle weighs 452 pounds.
Starre robbed more parts bins to see this motorcycle to completion. Along with the FZR transmission it also has a Ducati 900/1000 SuperSport swingarm and a headlight from a Cagiva V-Raptor.
The rest of it is mostly bespoke, including the trellis frame that was made in-house. This is said to weigh just 13 pounds on its own. Starre found other ways to cut the weight using full carbon bodywork and carbon wheels.
A Diesel Racebike?
The completed motorcycle did have respectable specs. The resulting 125 HP and 185 lb-ft torque gave the motorcycle a top speed of 155 mph. Eventually, the motorcycle caught the attention of Revo International, a Japanese company that produces biodiesel from used cooking oil.
To show off the potential of the Star Twin Thunder Star 1200 TDI, Revo and Star Twin decided to run a parade lap on the 2014 ManxGP/Classic TT on the Isle of Man. The idea here is that the parade lap would showcase that diesel engines did have a place in motorcycles and maybe with some luck, the TTXGP clean energy class would open up to Star Twin’s diesel bike. Japanese racer Yoshihiro Kishimoto was selected to ride the steed and the motorcycle was stripped of all of its road legal bits and was given a new color scheme of white and carbon with sponsor decals.
Star Twin’s hope was that the motorcycle would be able to run the Isle of Man TT in 2015. But for some unexplained reason, that never happened. This motorcycle was also never put into production, only existing of what could have been. Starre said that production of the motorcycle took about seven years and €300,000 to develop, making it one pricy machine.
Back in 2015, Starre considered making a kit of the Star Twin Thunder Star 1200 TDI where for €40,000 plus tax, you’d get a VW TDI engine, a transmission, the electronics to make it work, and the frame. You would be left to figure out the rest. Seeing that just one of these exists, it would appear that kit never happened.
After the bike’s failure to run the 2015 Isle of Man TT, the mirrors, lights, and license plate holder were put back on. The motorcycle most recently appeared for sale in late 2021 or early 2022 on Gallery Aaldering. It has since been sold. Hopefully, someone is out there enjoying this thing. As for Van der Starre, he’s still out there working on custom projects. I’m not sure how successful his diesel bike was, but it’s so awesome he at least gave it a shot.
(Images: Star Twin Techniek BV unless otherwise noted.)
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Thanks for a fascinating article Mercedes!
I daily’d a Golf TDI for more than 20 years, so I’m somewhat familiar with, and fond of, things diesel. I’ve had an M1 license for almost 20 years too, but haven’t taken the plunge and
riskedowned a bike in LA yet. As it happens, I was about to head over to North Hollywood yesterday and actually go sit on a few bikes in the 200-500cc range, but luckily I google streetviewed it first and discovered that the cycle dealership turned into an Enterprise rental car place years ago.I enjoyed your article about the diesel Royal Enfield too. 🙂
If you are convinced deisel is the way, I imagine the looser emissions regulations for motorcycles also make it attractive.
‘just because you can doesn’t mean you should.’
Pulling up to the diesel pump would be entertaining.
I know this happened quite some time ago but, even then the pursuit of an electric was more useful and marketable.
impressive numbers, unfortunately at that time you could get a V-Max that would handily outrun the Triumph as well as this Diesel, and all that for under 18K
this thing had to smell like shit, though, right?
Like I said before, Mercedes just needs to do a autopian road trip across India, buy every Royal Enfield diesel she can fit in a shipping container and ship it back here. After selling a bike to each one of us dozen or so diesel bike enthusiasts, she would have paid for a couple for herself!
I’d be curious to see it’s dyno graph. Most diesels have a painfully narrow powerband but some free reving engines exist
This thing rips like a diesel chainsaw… torque for days.
So, I’d really like to have a Lupo with 125 hp and 185lb-ft: talk about a blast to drive!
seems like if these engines can handle that much power, a propane injection kit is kind of like Nitrous to a diesel, if it did not detonate the little guy, then occasional burst of sleeper power in a lupo would indeed be a blast.
I have owned 2 Lupo 3Ls, amazing cars, both capable of going 118 mph flat out or achieving 94 mpg just tugging along with the trucks on the motorway (average was about 59 mpg). They have a cult following here (DK) keeping them running, so not uncommon to see one with 250K miles on the clock..
Also fun that it knocked the bottom out of our “green” tax system here, so you paid $23 yearly in road tax for one (average around 20 to 40 times that for any normal car)
The car itself was nothing to write home about, being quite flimsy and not very practical or beautiful. It did have one of the best steering wheels ever on any newish car though!
I’ve often thought about using one of those engines for something, but lack a bit of technical skill (and time..), so nice to see someone who has done it 🙂
Lupo 3L, a fine example of the stupidity of the legacy ice manufacturers: “vorsprung durch technik” my ass.
Why keep patching a inherently flawed technology (ice) by making small incremental fixes (they call them improvements) to a uphill battle turning a reciprocating motion into a circular motion.
VW, successfully, used the 3L to convince the politicians that the ice had a future.
Diesel gate was part of the same agenda.
I’ve got a Audi A2 1.2 TDi since new. It was supposed to be exported to Denmark, but shipped to a wrong country, sold to me, and I had it shipped to America. Long time ago. Battery cars were dreams back then, you wouldn’t Think driving cross-country on those then.
I have thought it was some corporate mistake on Audi behalf make such a masterpiece of a car. Somebody got sacked. And the car got killed after 2 years of production.
OMG, I forgot about this guy! I’d love to visit his shop some time but I doubt he has time for random lookie-loos. But I’ll bet he has time to show off his wares to a journalist visiting from America. By the way, sometimes there’s good deals on ORD-AMS flights, either direct or via Iceland…
Thanks for this one, that I’d never heard of it, kinda like a Munch Mammoth for a different space in time.
Also geez Mercedes I thought you’d have made the smart purchase of a Eva Track T-800CDI by now. Where’s my disappointed emoji gone? )-;
This definitely feels like a relic of Volkswagen’s “TDI Clean Diesel” advertising era, when it seemed like modern diesels were the shining be all/to all/for all solution to most of our problems – efficient, powerful, and also really cleans, nearly as clean as gasoline engines if you can believe it. As it turned out, well, yeah.
As it turned out, they actually were efficient, powerful, and significantly cleaner than gasoline engines.
Modern diesels literally are the solution to most of our problems, and that’s why they have solved a lot of problems for Europe. Too bad the EPA has a hard on for banning diesels.
Unfortunately the EU have a similar hard-on.
NOx emissions were way higher than gas cars.
somewhat true, but what is worse NOx or CO? It appears even in the US the NOx standards have changed to allow more NOx for diesels versus gas. but at one time, the key difference is that the US applied a single set of standards to petrol and diesel vehicles, while the EU allowed higher levels of air quality pollutants to diesel vehicles. In addition, California, and a number of other states which chose to adopt California’s rules, apply emissions standards which are more intrusive than federal standards. CARB needs to be dismantled, just saying.
CARB’s intrusive standards are fine by me. I grew up in the IE, East of L.A. When I was in elementary school, LA County had an average of 150 days out of the year where the air was Very Unhealthy or Hazardous to breathe. Your lungs would burn if you ran or exercised and the sky was brown instead of blue. Four out of the last 5 years there has been only 1 day where the air quality was Very Unhealthy or Hazardous to everyone. The IE (Riverside and San Bernardino Counties) are still the #2 and #3 counties with the worst air pollution in the US but it is way better than it was in the 1980’s because of CARB.
“Modern diesels literally are the solution to most of our problems…”
I’m not saying that there is no room for diesel in the future. Different propulsion systems are better suited to different applications. But you made a pretty bold statement, and I’m curious how burning diesel will solve most of our problems. Which problems?
At Starre we say no job is too big or too small. However we do say a budget can be too small. We never say no we charge enough so you say no. We are willing to do anything you want if the price is right.