Kickboxer Diesel and All Wheel Drive

Kickboxer diesel concept by Ian McElroy

Kickboxer diesel motorcycle concept by Ian McElroy

Remember Ian McElroy's Kickboxer? That was a really wild concept powered by the Subaru WRX engine. Well, Ian's at it again, he had been tossing around the idea of a diesel bike for some time and thought, "Hey, Subaru makes a diesel, it's more compact than the gasoline engine, it's powerful, gets great mileage, why not?" So he sat down and got to work.

Kickboxer diesel concept by Ian McElroy

Kickboxer diesel motorcycle concept by Ian McElroy

He says making the engine fit was relatively easy, but he also decided to differentiate the diesel bike from the original with new bodywork, swingarms, and a different turbo layout. Then, just for fun, he figured with all of that diesel power available, why not all wheel drive? So he worked up a second design with power going to both wheels.

Kickboxer AWD diesel concept by Ian McElroy

Kickboxer AWD diesel concept by Ian McElroy

The standard bike features lightweight composite bodywork, under seat radiator, front mounted intercooler, LED lighting, and under engine turbocharger. For the AWD version power is transmitted to the front wheel by way of two chains, a jack shaft, idler sprocket, and a drive axle with a U-joint.

Kickboxer AWD diesel concept by Ian McElroy

Kickboxer AWD diesel motorcycle concept by Ian McElroy

Ian is a stickler for detail, on his first Kickboxer design, Ian said, "I designed the model to be accurate and realistic enough to build a real bike from. If I had the money I could take the CAD files straight to a machinist, and have the parts made today." I assume, this diesel model was created to the same standards.

Wouldn't it be interesting to see someone with the funds, pick this up and build it?

Kickboxer AWD diesel concept by Ian McElroy

Kickboxer AWD diesel concept by Ian McElroy

Here's an additional closeup image of the steering:

Kickboxer steering closeup

Kickboxer steering closeup

Comments

  1. JustThunkin says

    Would it be interesting? Yeah and problematic. It occurs to me that with the front and rear tire traveling slightly different distances during cornering that more than a universal joint to the front axle would be required. Can’t say that I would be all that comfortable with a chain whizzing around to the front of my line of sight, either.

    • kitmotarded says

      I’m glad to see that the first comment I see points out the same flaw that catches my attention right off. It needs a differential between the rear and front wheels to account for differential wheel rotations and a U-joint for the steering. I love the outside the box thinking though!

    • BoxerFanatic says

      I would wonder if there is some sort of slip-limiting device in the intermediate chain junction. Maybe a variant of a slipper-clutch.

      The mid-chain goes from the drive sprocket to both the rear wheel, and another to an intermediate sprocket near the front swing arm pivot, which drives a third chain further to the front hub. If there is some sort of slip-able differential between the mid-chain and front chain, in that sprocket transition, I could see it working.

      It would be a challenge to work flawlessly, and remain reliable, but it could work, theoretically.

      But at that point, I am starting to wonder about an articulating motorcycle, with a flexible joint between the front and rear swing arms, to allow the bike to steer by bending in the middle, like an articulated truck, or simulate the behavior of a 4-wheel-steering capable car.

      I’m just sayin… if we are dreaming about wild and crazy stuff…

      • KC says

        I lke the idea of an articulated bike. I live in Colorado where most of the turns are done by leaning the bike in the direction of travel anyway. But I think a shaft drive would work best. I have a Buell that I ride in the winter, and the snow cables/ chains work well enough but AWD would make riding in the snow that much safer I think.

    • rotor says

      Guess you could use a viscous coupling like the softroader 4×4 cars do? but that would add more weight.

    • Barry Burdue says

      Yeah…. The chains. I hate when my pant legs get wrapped up in my bicycle chain! ….I couldn’t even imagine this tragedy. Love the diesel concept however.

  2. leston says

    I like the diesel idea. Lets build it. but all wheel drive with open chains flying everywhere? eh….not for me.

  3. Ian says

    Oooooh. :)

    Reminds me of the D1200R, I like.

    Chain drive is a bit of a downer, especially with all that exposed length by the rider as has been mentioned. I wonder what it’d take, mechanically, to set up as a shaftie?

  4. says

    As a Diesel, Muscle Bike – he has really hit it on the head -Sort of like it – the first pictures look a bit manga like but then – but why add AWD?

    There is also the issue of too much chain. AWD is best done with fluid, like on the Yamaha. You don’t want to use a 6 ft chain going around to the front, bringing in a whole host of gyroscopic issues into the equation!

    • Simon says

      Hydrolic drive is less efficient than a chain. I’m more worried about the lack of a differential. The mechanicals are the same as a fwd car.

      • HR Tanner says

        For my first point I would like to correct the missinformed notion that the front and rear wheels travel differently in a turn. This is a concern only when the two wheels are beside each other, such as the rear of a Trike, but when both are in line on a forward plane, there is no need for differentiation.
        I will make a Second point, that the set up would work great using the shaft drive system already found on many bike. It would just require the turning nuckle, that is already shown in the designs.

        • GRadde says

          “…but when both [wheels] are in line on a forward plane, there is no need for differentiation.” Here’s an experiment for you: take a bike, motorized or just a bicycle, doesn’t matter. Then, mark the point on each wheel in contact with the ground. Now, steer either left or right and move the vehicle along. You’ll notice that the markings don’t touch the ground at the same time anymore. This is because the front wheel has a larger turning circle than the rear wheel.

          Now, had this been an AWD, two-wheeled bike, you’d have a problem, in much the same way as two parallell powered wheels would in a turn. This thing needs some form of differential.

          Either that, or one could meddle with the idea of making both wheels turn equal increments. That would remove the need for a ‘diff, I have no idea what it would be like on the road though; probably rather oversteery.

          • Eric says

            We have other test versions of AWD (motorcycles) it is simple really, it work much like the bicycle freewheel, where once a speed is reached the you can pedal backwards and nothing happens except the clicking sound of the ratcheting mechanics. this is the same for a motor powered AWD on a motorcycle.. the faster moving wheel will be dominate the other will free wheel. hope this helps.

  5. Core says

    I thought it was pretty awesome looking image wise and the whole concept of a diesel bike, till you started talking about an all wheel drive version. . .

  6. Paul Crowe - "The Kneeslider" says

    We’ve covered numerous 2 wheel drive bikes on The Kneeslider. We mentioned the Yamaha when one came up at auction, the hydrostatic drive Racoon and the bikes by Christini.

    There are many ways to drive the front wheel, all have their pros and cons. As mentioned in the article, Ian added AWD just for fun, it may or may not be the best solution, but it’s an interesting idea and, problems can always be solved. That’s what’s fun about designing and building motorcycles.

    • Pancakefactory says

      agreed cad is one thing and reality is another. but thats why we have catea and solidworks.

  7. John Tangerås says

    Interesting design, but if it doesn’t have a centre differential, it won’t be long before the drive and/or gearbox is torn to bits. The reason for this is that the wheels will always have different diametres. Imagine a really big rear wheel and a small front wheel. Drive ratio for the chain and sprocket is the same front and rear, of course. Both wheels will travel at the same rpm, but the rearwheel will move a longer distance due to longer circumference of the bigger wheel. The small front wheel either loose traction or getting “wound up” like a mecanichal watch. If you drive the bike on gravel, ice or other loose surface it will be OK, as the “wind up” will be released into the loose surface by spinning or braking of the “wound up” wheel.
    The question of turning is not a problem, use the same mechanics as in any front wheel drive car (ball plunging joints).

  8. Arion says

    It doesn’t appeal to me aesthetically.

    Stupendous amount of work. Does his claim that it is ready for machining mean that he has also accounted for machining and assembly tolerances, maintenance clearances, and materials coatings?

    It looks like a service and maintenance nightmare. Does the entire top of the bike come off to service the intake system?

    I am skeptical that the small radiator will provide enough cooling for a very high compression ratio diesel engine. The exhaust pipe diameters look tiny compared to the size of the cylinder heads. I guess it must be a diesel.

    It might have been preferable to use shaft drive over chain drive, at some additional expense in weight, while still avoiding the relative inefficiency of hydraulic drive. Torque steer could still be a problem.

  9. BoxerFanatic says

    Wow. As a boxer fanatic, and multiple-subaru owner, this is very interesting to me.
    -But a bit much.

    How does the front drive chain maintain tension, with steering, braking, and suspension compression forces? The hub must have some sort of CV joint in the hub if the chain sprocket doesn’t steer with the wheel.

    Shaft drive seems like a better idea, if at all possible.

    I like diesel for what it does well. Very torquey and with high output per unit of fuel, but it isn’t exactly rev-happy. Not a sports car, or a sporty motorcycle engine, I wouldn’t think.

    I wonder how the subaru engine compares in terms of size to the likes of a Gold-wing flat 6. It is obviously much bigger than a BMW boxer.

    Very interesting as an engineering exercise… and I admire it as such, but I wonder about the practical implications of such a complex machine in real world terms.

  10. B*A*M*F says

    Man I love this thing! What a cool looking concept. The AWD looks a bit tacked on compared to the RWD concept. The idea of a turbo diesel boxer bike is pretty sweet.

  11. mark says

    Nice study, but it seems like that engine is mounted awfully high up, creating an awkwardly high center of gravity.

  12. discontinuuity says

    You could do it like some 2-wheel-drive mountain bikes: gear the front wheel slightly slower than the back, with a freewheel. That way the front wheel only gets power if the back wheel is spinning/loosing traction. Sort of like a Detroit locker axle.

  13. mechtech retired says

    Its the twenty first century guys! its time that the gas guzzling internal combustion engine was dumped!!

    The brits! were using small efficient Jet turbines in the Rover sedan cars over fifty years ago! we are all going where the gas companys want us too! >>its breakaway time guys!! lets go turbines or electric>> trouble is soon as someone makes a good working model!> like all of the electric cars made in canada in the last ten years etc. they are bought off by guess who??

    • michael says

      they were NOT that effecient, clean burning yes..but not on MPG’s though
      look at the Y2K, i think it only does like 6mpg?
      and it is a small effecient engine

  14. Adrian says

    Has anyone tried putting an electric motor on the front wheel? Then you wouldn’t have to worry about differentials or steering linkages, might add too much unsprung weight though.
    I always thought that’s how the “akira bike” would work, with some kind of powerplant in the middle and electric drive on each wheel.

  15. mattigan says

    hey guys I love this concept, but as a real, for REAL motorcycle, not a just-for-rendering-drool-fest type of thing, none of you informed motorcyclists out there have brought up the cooling issue. I love the concept of the WRX powered motorcycle, but at least the original concept had intercoolers. It did not have any sort of radiators for the liquid cooling circuit though. the intercoolers could help, sort of, even if they were not pointed towards the airflow moving across them. Big ugly cooling radiators were not part of the design, the WRX is a water-cooled engine. I would hate to have to see a gigantic ugly radiator with a fan like a boss hoss in front of this lovely motorcycle but how else do you keep a 2200-2500cc turbo performance engine cooled without water-cooling and intercoolers. they are ugly but needed for this to be anything other than a boulevard idling poser bike. I am not trying to criticize the beauty of these nicely rendered things but they have to function in the real world, and in the real world internal combustion engines produce heat that has to be dealt with.

  16. Bob Nedoma says

    While I don’t think much of the whole thing, I would just love to try to test-ride one of those, if one was ever built, just to see what happens when I start loosing traction in the back and the front takes all the power while leaning-over 40 (something) degrees.

  17. Thom says

    The cooling issue WAS brought up- there’s an under-seat radiator and front-mount intercooler. I also believe the front drive is very possible, if overly complex with the added chains. Steering is obviously hub-center, similar to the Bimota Tesi. The cv stub axle was mentioned in the article.
    On the whole, I really like the concept. I’ll like it more if someone builds it!

  18. Mark says

    I think the most interesting aspect of this design, and possibly the most beneficial is not the 2WD system, but rather, applying the front drive system to the rear wheel for 2 wheel steering. Forget the 2WD system, apply this to the rear, and steer both wheels.

  19. Sick Cylinder says

    I like it – but I would like it more if it was simplified so that someone could build it.

    very interesting to launch a range of ideas, but it might have been helpful if someone had whispered in the designers ear “Enough already”

  20. Fred M.l says

    Driving the front wheel on a sport bike seems like it’s increasing the likelihood of a front-end tuck as the smaller front tire copes with both steering and driving the bike. That problem is why front-wheel drive cars tend to understeer. It also complicates the design of the front tire and adds a lot of unsprung mass to the front of the bike.

    Enough on the front wheel drive.

    The diesel: I love the idea of diesel motorcycles, but sport bikes are the least appealing platform to house a diesel. Diesel engines have characteristics that make them less-than-desirable for a sport bike. They can’t rev as fast as gasoline engines due to the slower flame front from diesel fuel. Although they produce prodigious torque at low RPMs, the ratio of redline to lowest usable RPM is not even close to what one finds in a modern sport bike engine; that means more gear shifting and maybe even more than 6 gears to get adequate performance. Because of the stresses that compression ignition and 20:1 ratios cause, you end up with an engine that’s heavy. It has a heavy crank, heavy rods, heavy pistons, heavy cylinders, and heavy heads. It has a fuel injection system that must operate at about 15,000 PSI range to properly atomize the fuel for performance and emissions reasons. That’s more weight.

    Now, build a diesel adventure bike, full-dress touring bike, or cruiser and you might find yourself with a real market. If I’m trekking in some third-world country, the idea that my bike could run on filtered cooking oil, diesel fuel, or heating oil, is kind of appealing.

    • Michael says

      well, Audi has been destroying everyone the past several years with a low reving diesel race car!! NOW, everyone is crying, so audi can only use a 6 cyl instead of a 8, 10, or 12. all that did was lower the weight of the car, and still gave them the same HP and torque!! Now that audi has proven it AGAIN, Pugeot is in there with a diesel. By the way, Cummins has diesels in the Indy500 over 60 years ago..They would have won, but the turbo sucked up some trash, and that was that…..
      With the higher torque, do not need high fast reving engines…
      but still…probably get 100mgp??

  21. Jim says

    Looks heavy and probably would be when all the mechanicals are sorted. I’ll speculate that it will handle like poo and that having the front wheel providing propulsion will result in some spectacular low sides on pavement. Powering the front wheel is seductive in theory but seldom results in superior performance. IIRC correctly Yamaha played around with AWD on a dirt bike and not much came of that.

  22. Thom says

    Nobody’s seem the video of the AWD Yamaha R1? Check it out on Youtube If you don’t believe a spirtbike with AWD is feasible.

  23. SteveD says

    The Subaru engine would be fun. I’m not sure about the AWD, however. OK, I am sure, and I think it’s probably a bad idea. But the diesel boxer powered bike would be cool.

  24. Scotduke says

    Not pretty – but pretty interesting. I drove a prototype 2WD motorcycle in the 1990s that was based around a Yamaha XT. It had its flaws and the steering while on throttle had its issues but the concept was never fully developed. I thought then that it had potential and I still do. But this thing needs a facelift if nothing else.

  25. Boog says

    Kind of interesting, like an all-wheel drive articulated farm tractor. Why the hell would you need this for street riding?

    I guess you could use this \thing\ as a garden tractor as well as transportation.

  26. Shane says

    I love the awd idea but why on earth would he use a chain drive? Wouldn’t a set of shafts be a much easier and safer alternative? And,since your basing it on a subaru why not come up with a variable ratio transfer case?

  27. Stew Cameron says

    love it. I have owned Subaru since 1978, and have owned 14 motorcycles over the last 35 years. You have a great idea, but I feel the more simple the concept the better. Think about rear drive only. Belt drive would be very quite. Your target market just might the older rider that would look at more than speed (not saying it is a bad thing). Can’t wait for the video.

  28. Wood Gas says

    In my limited stable I have a dirt bike, a cruiser, and a Rokon 2wd. Riding the 2wd is nothing like riding anything else. For the first 10 or 20 hours it really wanted to be on top.
    Now I can pretty much go anywhere with it but it ain’t kike riding a bike!

  29. Mick Sturbs says

    Why use a car engine anyway? there is so much enginering just to squeeze everything in it would be easier to build a 2 stoke diesel from scratch (there is an X format concept bike in Kneeslider).

    Hydraulics are inefficient for power transmission, but is that inherent to hydraulics or is it because off the shelf components are used with no thought about smooth fluid flows through the system. I dont know just asking the question.

    Another option is direct drive to the rear wheel (via toothed belt) with dog clutch. Use hydraulics to get it up to speed then click in the direct drive and the hydraulics stop turning. Diesels have a flat torque curve and a stroker with 2x as bangs per rev even more so. Any hydraulic losses would only apply at low speeds where power demand is also low(er).

    For those who dont get 2 stroke diesels – they are NOTHING like petrol strokers of old. They use a wet or dry sump and air is force fed into the cylinders via blower and turbo. There is no crankcase compression, no expansion pipes, no total loss lubrication and non of the part throttle chuntering. A 500cc X-fornat would be very narrow and small diameter having no cams, no valves etc “above” the pistons.

    2WD is ok for a forest bike – pretty much a 2 wheeled quad but narrow. For normal use rear wheel drive is all that’s ever been needed.

  30. Mick Sturbs says

    In answer to those who think “high tech” electric is the clean green way to go…

    Where does the electricity come from(?) – coal gas and oil and nuke with a very poor energy conversion rate by the time the bike/car gets it onto the road. Electric cars are clean at point of use but otherwise energy wasteful and dirty. Not to mention the battery issues – toxic heavy metals, etc.

    The only viable option is lots more nukes which can at least crack water to hydrogen as a byproduct. That would be carbon free power. But got to first show that nukes are actually safer than the other technologies and get the safety scheme sorted its currently about 100x more fussy that it needs to be.

    But no-one ever relaxes safety rules or rethinks how much is appropriate and everyone is scared of nukes because of bombs and the Cold War panic mongering. Chernobyl was nasty, but compare the actual damage done to that of a large coal fired plant (which is also surprisingly radioactive). This year alone there have been a few hundred deaths in coal mines around the world. So many, no-one even thinks about them.

  31. Erik Lee says

    You NNNEEEEED to contact DIESEL POWER magazine to let them cover this story ! Don’t get hung up on the 2WD. If this gets covered in a Diesel Afficionado’s magzn like DP or Diesel World . . . . you’ll find probably more than one built !

  32. Simo says

    2WD ? 2 el. motors in each wheel . LPG Turbine? Sure – blocked with electric generator , with optimised rpms to utilise turbine efficiency . . what about thet idea?

  33. island antics says

    Few things I noticed:
    a) rake angle is too excessive
    b) rider sits to far back on the bike, therefore uneven weight on wheels making front end too light
    c) how does the damn thing steer with acres of chain? CV type contraption in hub?
    d) hose thing in front wheel pointing forward and too close to hot rotor!
    e) front shock absorver operates by extension, not compression?
    f) agressive racer boy posture on basically a cruiser bike wheel base length, weight and rake
    g) front swing arm will be chewed away with slack chain… no tolerance for 25mm or so chain slack
    and biggest downside to AWD…
    No ability to power slide! To much gas and the front washes out as opposed to back end stepping out.

    • todd says

      You need to take a second look.
      a) judging by the location of the lower link compared to the axle center it looks like it has about 23-24 degrees of rake and 3-1/2″ of trail – pretty typical.
      b) the engine itself weighs around 300 lb and is placed as far forward as possible. The seat doesn’t look any farther back than say the seat on a GSXR600 which has nearly 50-50 weight distribution.
      c) how does a front wheel drive car steer without turning its axles? That’s right, a CV joint.
      d) how close are all the hoses on a fuel system to the engine? The rotor does not get THAT hot and it’s up front where all the air flow is. He may want to keep it from flopping around a little.
      e) shock absorbers work in both extension and compression. The spring itself is likely in compression like on a Buell.
      f) scaling the image with the wheels looks like the wheelbase is around 52″, the same as a Buell. The handlebars look like they are placed a bit farther back than typical making for an easy reach.
      g) the front multi-link suspension could run with close to zero chain slack without any issues. The design of the rear requires slack though.

      There is a differential on this bike (wouldn’t work well otherwise) that would allow the wheels to turn at different rates. It’s not clear to me how a driven front wheel would behave in a hard turn under power. Maybe both would slip. We’d need to build it and test it.

      -todd

  34. Brian says

    Dual driveshafts, with an LSD or posi diff, or possibly one that locks electronically, perhaps from modded BMW bike shafts, would be incredible. Would eliminate the lethal slash to the head a broken front chain could deliver.

  35. Ryan says

    A possibility would be dual drive shaft with a CV joint in the front. Now that may take care of the steering but as far as the actual cornering on the bike, there would need be gears such as you would find on a Mt. bike on both front and rear wheel. This would allow ether wheel to travel a different speeds while maintaining power to at least one wheel at all times. With that you would have to rely completely on the brakes to stop, which may not be a bad thing since the compression of the diesel engine may cause wheel lock.

  36. crazy phil says

    I’ll start out by saying in my mind the aesthetic epitome of motorcycles is the Manx Norton. I ride a 1200 Goldwing… So my epitome and reality are obviously incongruent. In my mind this is as ridiculous as the BS “Tomahawk”!. Was this designed by anyone who has ever ridden a motorcycle??? In forty years of riding I must be getting up to the 200 k mark. Anyone out there paying any attention??? I didn’t read all the comments, but the ones I did read, no one MENTIONED THE FACT that the engine is mounted WAY TO HIGH, for goood stability! That chain drive is stupid, looks like a great candidate for coming off and is one step more dangerous the the stupid V Twin open belts. I think some of your readers and the designer of this, are idiots from Microsoft, and the closest the have ever come to a motorcycle are from behind a keyboard!

  37. HPNOTIQ says

    Scratch the AWD. Go with the standard Rear Wheel Shaft or Chain drive setup. Thats it! problem solved!!!!! Now what we got ourselves (?) DAMN!!! A DIESEL TURBO BOOSTED INTERCOOLER POWERED LOCOMOTIVE ON TWO WHEELS! Can feel the adrenaline pumping already, just imagining the acceleration it would have with a slight twist of the wrist.. Awesome! Should have a pillion seating option though, for someone who will sit behind and scream like crazy, on the 0 to 200 speed test runs!! WICKED Design!! Great..

  38. Hugh2170 says

    Centre diff for the 2 chains is ridiculously easy to do where the shaft comes out of the gearbox. Looks like that is what is going on here anyway. Would be better with belt drives. This thing looks awsome to me. C of G will be high but that will make for very quick changes of direction……probably too quick ! Love the idea of a diesel. All that torque. I run a Buell 1125r, it pulls sensibly from 4000 rpm to about 10000 rpm ie 2.5 fold increase in rpm. Diesel will pull from 1800 to 4500 rpm maybe more…….2.5 fold increase in RPM and the torque will hit in much earlier from the turbos. Go for it.

  39. Ingvar Tautra says

    The problem with differrential between front wheel and the rear wheel are lots of solutions for. The chain is easy to capsul inside a cover. The biggest problem is the weight. Diesel engines are heavy, the two wheel drive makes the bike even heavyer… but of course, that is just prolems to be solved. You have to ask what the reason for making a 2-wheel driven bike is?
    In my opinion the bike need another designer, it looks rather ugly. But that is just my opinion.

  40. Dave says

    How much steering lock does this have? We know bikes use next to no steering out on the road but parking and slow speed need proper steering. I cant see enough space for the front wheel to swing before it hits the swing arm.

  41. victor says

    i am a monowheeler,though i would prefer while on two wheels to have a two wheel drive bike.during the 80′s a neighbor of mine who i used to ride bmx bikes with had a two wheel drive system on his bike and it was awesome.it totally changed the way freestyle bmx was for us both.i certainly have not given up on the two wheel drive bike.for me i have just been anchored with ignorance and the lack of cash to buy the tools to get it done.it is not a pipe dream,i have currently made one as a prototype that works it just needs to be refined into a center hub steering or hubless wheel.don’t give up Ian,the ignorant used to try and shoot down Henry Ford and the Wright brothers too..

    • Alistair McKenzie says

      I think hydraulic drive is the way to go, and if it works on the front as Yamaha have done why not on the back as well, have the engine powering a robust hydraulic system for both wheels, power assisted braking and steering dampening, and fit the hydraulic drive within the forks and swingarm with direct drive through rotating axles. could lose alot of weight with smaller more powerful braking systems although there will be weight in the hydraulics.

  42. Rene says

    An electric motor/generator at the front wheel utilizing regenerative braking forces to assist recharge could be the go.