Diesel Motorbike

Discussion in 'General Questions' started by jared8783, Jun 13, 2009.

  1. jared8783

    jared8783 Member

    Has anyone ever done it succesfully?

    Could you imagine the gas mileage you would get from something like that?

    I haven't seen a thread on any site discusssing it and am trying to get some conversation goin about it. I think that the idea of a diesel moped would be great on account of mpg's. Don't get me wrong we already get great mpg's but could they be better?

  2. SimpleSimon

    SimpleSimon Active Member

    There has been extensive discussion of the topic on this board in the past. Do a search, you'll find it readily. The biggest problem is the engine - where are you going to get a 50cc or smaller diesel?
  3. wheelbender6

    wheelbender6 Well-Known Member

    I have seen small 10HP diesels for sale from some of the tool stores. They are considerably more expensive than gas 4 strokes. I'd love to run my mobike on french fry oil.
  4. give me vtec

    give me vtec Active Member

    I would think the bigest problem would be the direct injection necessary for a diesel to operate properly... you would need a very high preasure fuel pump and the electricity to run it...
  5. arceeguy

    arceeguy Active Member

    Mechanical injection pumps have been always been dominant in diesel engines. You only really see the common rail electronic systems in cars and trucks. Single cylinder non-road diesels use mechanical pumps.
  6. SimpleSimon

    SimpleSimon Active Member

    Yet again, you run into the size/weight issues, though. The smallest commercially available single cylinder diesel I have seen for sale was a Lister style low speed stationary engine with a jug size of 96 cc, and weighed 61 pounds. Even that isn't apparently available anymore.

    As for the injector issue - it isn't an issue.

    Here's the description of the HDT (Hayes Diversified Technology) diesel engine developed for the US and British armies:
    So, aspiration really isn't the problem. Note that displacement, though - you ain't gonna put that thing in a bicycle frame and motor away.
  7. arceeguy

    arceeguy Active Member

    While frequenting some "off grid living" websites, I stumbled on the ChangZuki Changfa diesel powered Suzuki. Cool project, but the builder needs some serious dental work. (been living off the grid too long. lol)
  8. give me vtec

    give me vtec Active Member

    interesting... I have a question though. Would an aluminum frame bike hold up to that kind of torque?
  9. Nitrohorse

    Nitrohorse New Member

    Have you looked closely at the engine cradle? I wouldn't sit on that bike let alone drive it. It appears that the builder used black pipe and plumbing fittings to create the lower frame. Not to mention the questionable welding on the attachment points.
    I'm not trying to be sarcastic, but that bike does not appear to be safe.
  10. Skyliner70cc

    Skyliner70cc Active Member

    gas mileage would be awful since compression ignition engines don't run on gas :)

    I'd bu one if they were available with the necessary turbo.
  11. hawaiioutdoors

    hawaiioutdoors New Member

  12. HoughMade

    HoughMade Guest

    Not a MB, but here is a link to a company doing real, well developed diesel motorcycles.


    They modify a Kawasaki KLR650 to run on all grades of jet fuel, kerosene and diesel. Here is the U.S. military version (M1030M1) used by the marines, Army and Air Force.


    Some highlights:

    single cylinder, liquid cooled
    32.5 hp (33 PW)
    96 mpg
    408 mile range
    90+mph top speed
    Last edited by a moderator: Jun 16, 2009
  13. i already get between 180-200mpg why would i want more.
  14. EsQueue

    EsQueue Member

  15. s_beaudry

    s_beaudry Member

    Now that is a heak of a find and a heak of an engine for a pusher!

    Definately useable, the only question in mind is that these diesels engines definately have a different rpm range. An off the shelf centrifugal clutch would not work I am thinking.

    I am sure max torque could spring one the right way for ~$100 or so maybe...
  16. velosolex

    velosolex Member

    built a diesel motorcycle

    I built my own diesel bike 3 years ago using one of the Yanmar clone 10hp electric start engines found on eBay. My engine was a "Kama" clone and designed for generator use. I had to modify the crankshaft end to accept a Comet 500 drive unit (no, this was not fun or easy). My donor bike was a '79 GS850 shaft drive Suzuki that had been parked outside for 10 years or so (yikes!). I also had a GS750 bike to use for parts. I took the GS750 swing arm and modified it to fit the GS850 frame (not easy either!), and went from there. I had to design and build a jackshaft, engine cradle, and fit up a huge 70 tooth #50 rear sprocket. When it was all said and done, I had a bike that would run 50mph and wake up everyone within 1 block where I was riding due to the engines knocking (air cooled aluminum engine case). I sold the bike to a friend 14 months ago cause I needed the cash, wish I'd kept it. From an engineering stand point, it was a 50% success: bike frame was way too heavy and my welding sucked because of the equipment I had at my disposal. Drive train was okay but I don't like Comet torque converters. Jackshaft's suck, but mine worked and still does. 10 hp engine will blow up someday; the design is for stationary use, not bikes.


    PS: there are photos of my work on Yahoogroups
  17. robin bird

    robin bird Member

    SEE THE MOPED ARCHIVES !! the Germans had one in 1956 called the Lomex --i beleive --it could run on any fuel and had adjustable compression not much power but great mpgs
  18. SimpleSimon

    SimpleSimon Active Member

    Had is the operative word here. As I said, I've searched, and cannot find a diesel engine for sale that is small enough to be appropriate for use as an assist engine on a pedal bike.
  19. velosolex

    velosolex Member

    I've read up on the German diesel over the years. The Lohman was a 18cc unit and did not have fuel injection, here is a link to a good site for information:


    From what I've learned, the unit was subject to overheating and really to small to be practical. I feel a 50 to 100cc unit would be more practical for actual use, but it would need fuel injection rather than a carb like the diesel model engines have.

  20. s_beaudry

    s_beaudry Member

    Has anyone ever thought of retro-fitting an existing engine to run diesel or such?

    I know the compression is much higher and so is the wear on the components, but with a little tweaking, and swapping of parts, a somewhat reliable diesel engine could be made out of an already existing engine?

    Possibly starting with the infamous Harbour Freight 79cc 2.5hp engine that goes for around $80 with the 20% off coupon...

    Any thoughts on the merit of this idea?

    Anyone know of an engine (small cc) that could be converted?