Just following up on yesterday’s post about the Thunder Star because I was rereading that article in Sport Rider. They toss in one statistic that I find pretty amazing, almost to the point of unbelievable. The Thunder Star gets 150mpg! It’s in the article and on the cover so it isn’t a typo, of course they call it a V-twin on the cover, too, and it’s a triple, so… I didn’t mention it yesterday because I was a little hesitant, can that be true? That’s the sort of mileage you would expect from one of those Solex motorbicycles or various mopeds but from this? If accurate, that should prompt an awful lot of development in this area.
Last week, I was talking to a guy who runs a diesel car, a VW as a matter of fact, and he reports some pretty high numbers, up around the 50mpg mark, and when you figure this bike only weighs 450 pounds with a VW diesel, it sounds plausible. There’s been so much development of diesels lately that we may be seeing a big turn in that direction. Interesting, but I think I’ll wait for some confirmation of that mpg number.
ron pidwerbesky says
please a touring model.
David Woodling says
It’s all about aerodynamics, weight, and engine output. Not only Diesel but Gasoline engines with a light bike, around 500lbs, and a proper hp and torque output, say 90hp and 50ft/lbs or so, and a good faring for touring, say a modification of the faring on the Hyabusa, and proper gearing for cruise to match the HP and output and you to can have a bike that gets 80 plus mpg. Wind and gearing are the killer on mpg. Low gearing can give you the acceleration you want but kill you mpg. It’s all in the balance. Links on the web to the guys that build streamliners and motorcycle aerodynamics can give clues as to what you should have for a high mpg cruise bike including calcs on gear rations, hp output ect. I found in building my kawa these articles to be most helpful and was able to significantly improve the mpg on my bike.
Dan Moyer says
My last 2 cars have been VW diesels. The first was a ’91 Golf, 1,600cc, no turbo. I got 50mpg or better. The current one is a ’96 Jetta, 1,900cc with turbo. It gets over 40mpg. I’m a sales rep and average over 2,300km per week, so I need the mileage. I wouldn’t be surprised if a 1,200cc diesel bike at 450lbs could get 150mpg. Look at the torque. 165ft-lbs. Can you imagine the gearing you could run on this thing? My cars cruise at 100kph running about 3,300 rpm. You could easilly gear this thing to get 100kph at something like 2,300rpm. Yup, I wouldn’t be surprised to see 150mpg.
Antonio Simmons says
E-mail all the motorcycles that are automatic by Suzuki in the range os $4,500 to $7,000.
todd says
It does not stand to reason that reducing the RPM will increase mileage. It may be very well that the VW diesel provides its highest torque and highest efficiency at 3,300 RPM. Diesels are ideally run as close to their peak power output as often as possible for highest efficiency and durability. If you geared the motorcycle for cruising at 2,300 rpm, or 30 percent below optimal RPM, you most likely would experience reduced mileage and shorter engine life. If you just accelerated higher to bring the RPM’s back up to 3,300 there would still be a reduced benefit due to the greater amount of wind resistance at higher speeds. There is an optimal combination of power range, gearing, and speed to achieve the highest mileage in a vehicle. Often the engine’s capacity or power output is reduced to achieve this. This is constantly proven out in the diesel truck shipping industry.
-todd
Rob Sharp says
150 MPG sounds good at first, but can you imagine where the cost of fuel would go? And we think it’s high now! If it were possible (150 MPG.), it will only be a short time, and the fuel would be priced according to fuel mileage obtained. It’s happening now. Just look at where the prices were, and are today. Diesel was quite a bit less than gasoline, but now matches or surpasses the price of gas. It’s not just the demand, it’s the fact you can go farther than on the same amount of gas. Get people to use it, have them buy the vehicles that use it, and gouge, gouge ,gouge. I’m certainly not against great fuel mileage, just the fuel giants ripping us off and destroying the break throughs obtained for their own greed. Ok, I’ll get off my soap box now.
mad1 says
So has anyone modified their street motorcycle with a dustbin fairing? How come we had 70hp 160mph bikes back in the 60s, but now, the same 160mph needs 110hp?
James says
As far as the mileage, this bike SHOULD get this kind of fuel efficiency. The VW Lupo that the engine is pirated from gets a solid 80 (yes, 80) mpg in a two door aluminum unibody four seat chassis. Furthermore for those following the military diesel bike that just set the land speed record @ 192.5 mph, it achieves 110 mpg @ 55mph. And that is from an AIR cooled INDIRECT injection NON TURBO single cylinder!! These #s are for a mil contract bike, too, so it’s not some souped up prototype. Unfortunately, for those who want one they are planning to strafe their buyers for $19k if they want one. Hopefully the Dutch will be a little more realistic.
neil says
Seems like everyone here thinks this is a good idea, but the crunch question is would you buy one? If you were in the position of only being able to run one bike, what would the formula have to be to make you choose a diesel over a conventional petrol fuelled bike?
w.c. hill says
aerodynamics are what mileage are all about, Motoguzzi came out with one that was unbeatable in 1956, instead of long and swoopy they reached down to the ground and scooped the air around and over, coupled with a fuel efficient diesel motor and a proper constantly variable transmission you should be able to get 150 mpg at highway speeds, I’ve owned 5 vw diesels and the turbo charged ones not only have more power but better mileage too, I currently have a 96 vw tdi, a 86 ford ranger 4×4 with a turbo charged toyota 2.2 diesel, and a 2006 smart car and the best it has gotten so far is 84 mpg, the body style on it is far from the conventional aerodynamic shape, much closer to the dustbin shape
Bruce says
How about 470mpg? Craig Vetter (the fairing guy) addressed this in the 70’s & 80’s. Here’s his site: http://www.craigvetter.com/pages/470MPG/470MPG%20Main.html
Steven Leek says
Charlie Perethian, an associate of Craig Vetter and owner of Parabellum, got 104 MPG with a passenger on back. He discusses this on the Vetter Site. He emphasizes that his was a motorcylce built for day to day street use. He got over 150 MPG with the same bike in a more controlled setting. The bike was a 1983 Suzuki Tempter Gr650, a bike that was engineered intentionally to get good fuel mileage at the expense of some performance. Perethian reports that he never modified the engine internally or even had it apart. Suzuki screwed things up when they marketed this bike by putting the wrong final drive ratios, a fault that can be owner-corrected.
Hugo says
For my graduation project in 2001 I tried to design a motorcycle which could get a fuel mileage of 118MPG (if I remember correctly) with the dynamic handling and fueled-up weight of a (comparable) SV650; weight distribution was 54/46) seating position was comfortable like a sports tourer. To achieve this I positioned the rider around the front wheel, sitting low (625mm). This way a better teardrop shape (top view) was achieved and the frontal area was comparable to a Honda Blackbird. By using a hybrid engine (V-twin and electrical engines in the gearbox) and positioning all heavy parts around the CoG it was shown in simulations made by Tony Foale that the handling was pretty dynamic despite it’s 1490mm wheelbase.
The front fairing is also the frame (from carbon fibre) while front suspension is a variant of the Troll TRX system.
By styling the bike like the 50’s racebikes (Guzzi V8 for instance) good aerodynamics can be achieved (those bikes had excellent Cd values altough crosswind is a problem)
After 7 years it still wonders me why no manufacturer has looked into the issue of fuel consumption. Was my “vision” that far fetched in 2001 😉
Some images:
http://s3images.coroflot.com/user_files/individual_files/134713_B8omRecLt1bPzEljwvLJFszEO.jpg
http://www.bottpower.com/fotos/aerodinamica2.jpg
http://www.bottpower.com/fotos/taurus-final1.jpg
http://www.bottpower.com/fotos/taurus-final2.jpg
rex webb says
How i wish my late dear friend “Ernie Dorsett” could still be here.He produced 8 Matchless and 1 AJS Dorsett Diesel motor cycles.I have one of the Matchless models.
It has a Fuji Robin engine 412cc , 10BHP at 3600 RPM. This gives up to 200 MPG. with a crusing speed of 55-60Mph.On the trip “Lands End to John-o-Groats” we avereged 185MPG.Now a bike with a car engine weighs so much more ??.
As for the USA Diesel Bike doing 195MPH ?? i thik that is not correct ??.I hope to hear from any one with a “Royal Enfield” diesel powered by the same” Fuji Robin” Engine.Over 120 of this model were made to “Ernie Dorsett,s” design.