Bodging up a diesel motorcycle

[Alex] has been working on a diesel motorcycle project for a few months now, and the project is finally bearing fruit. It’s quite an accomplishment for something [Alex] describes as an industrial Chinese engine, a modded Honda Superdream, and a few Royal Enfield parts thrown in for good measure.

[Alex] bought his Honda CB400 from someone who had already done a diesel motor conversion; a 200cc single-cylinder motor provided just enough horsepower to putt around town. [Alex] wanted a bike that could keep up with highway speeds, so he replaced the wimpy 200cc motor with a 406cc diesel engine used for industrial purposes and an amr500 supercharger.

Although we’ve seen a few insane motorcycle builds, most of Hackaday’s bike builds focus on electric or scavenged parts motorcycles. If you’ve got an awesome motorcycle build you’ve been working on, send it in on the tip line.

You can check out the video of [Alex] testing out his new motor with vegetable oil (for him, it’s easier than getting diesel fuel) after the break.


  1. Willaim says:

    The video might as well be a soundtrack its worthless as you see one red lght and a puff of smoke and thats about it….

    Why does it take so long to start?

    • Natalie says:

      does it have glow plugs? otherwise, cold starts will be painful.

      otherwise, his webpage is maxed out on BW and his host is blocking requests

      • Alexander says:

        All fixes, Its direct injection, so cold starts shouldn’t be a problem as long as the engine is stopped and started on diesel. It does have a port at the top for injection a small amount of oil to increase the compression to aid cold starts, but once the fuel system is bled its much better.

      • Natalie says:

        Alex, I was thinking that the VW TDI has glow plugs, though it may not matter much as motorcycles are warm weather transportation.

  2. Willaim says:

    Went to his YouTube page much better (VISIBLE) video there
    Diesel Idle Test:

  3. rasz says:

    his isp wont be pleased

  4. spiralbrain says:

    Royal Enfield (India) used to build Diesel bikes till few years ago. It sounded like a generator and was good enough for 160 miles to a gallon. I wonder if direct injection technology can revive diesel motorcycles. It is perhaps the only classic motorcycle still being manufactured today.

  5. barry99705 says:

    Doesn’t Harley make diesel dirt bikes? Pretty sure it was Harley I saw the combat control guys using.

  6. No One says:

    I really wish my state were more amenable to custom creations. As it is I don’t think I could get something like this to be legal on the roads even though I’d love to have a 160 MPG bike.

    • bhtooefr says:

      Depends on what state you’re in, but there’s two ways to do it.

      The first way is to just not tell the government that you’ve made it a diesel. In most states, that works quite well. Even in the states that do care, if you’re careful with your engine choice, it’ll probably slip under the radar. (Hint: the Ruggerini MD150/151 and MD190/191 are far better engines in every way than the Chinese Yanmar clones popular for diesel motorcycle swaps – barely any more weight, and nearly twice the horsepower in some cases – while looking like an actual (old, but still) inline twin motorcycle engine once the shrouding is removed.)

      The second way is to use an EPA rule, that allows anyone to build a single non-compliant motorcycle in their lifetime.

      • Alexander says:

        I was saving money on this build, I only paid £300 for engine, brand new!

      • bhtooefr says:

        Alexander: True, there is the cost factor.

        (Availability is a problem in the US, too – it took me months to find the MD150 I have lying around for a future project… and then in the end, that project might work out better based on a 300cc Kymco fuel-injected gas scooter driveline, due to size and power considerations…)

      • Ketzer says:

        It is a shame they insist on calculating emissions-per-gallon instead of emissions-per-mile.

        Diesel is the future though. It is a hell of a lot easier (cheaper) to make a diesel fuel substitute than it is to make a gasoline substitute.

  7. Sorry about that, I host the website, so have given it unlimited bandwidth, had no idea I would be featured on hackaday!

  8. Yeah the long start was due to A) veg oil )b) purging the air out of the fuel system.

  9. Scott says:

    Great project, but from the looks of things the glow plug and starter circuit need a looking after. Should be cranking faster and a good plug will light things off very quickly. If necessary you can use the Norwegian Fishing Boat method – heating the cylinder head with a torch.

    • Alexander says:

      None of the wiring is connected up so I was using a jump start, although that’s the normal starting speed, high compression and one cylinder make that odd sound :)

  10. Rick says:

    It might help if you heated up the head with a propane torch first.

  11. Rick says:

    OOPZ. I shoulda read the comments first. Scott- good thinking.

  12. Alex says:

    Diesel bikes are cool! I’d love to build one some day.

  13. vonskippy says:

    In the near future, where all personal transportation are diesel motorcycles running on the new and improved organic fuel called “soylent diesel”, an innovative young man makes a horrifying discovery….

    “Soylent Diesel, it’s made out of PEOPLE!!!!!!”

    • Willaim says:

      Hey, as long as we aren’t eating it I’m all for Soylent Diesel
      Actually that sounds like a great idea too.
      Think about it eventually we are bound to run out of places to plant dead people and cremating them creates pollution anyways so might as well get to the store a few times with grandma AFTER she dies haha

  14. alxy says:

    The 10hp Chinese Yanmar diesel clones are expensive ($>500) as well as unusually loud and smokey, even for a diesel. They’re OK for a tractor, but not the best for a bike.

  15. Willaim says:

    Hey, as long as we aren’t eating it I’m all for Soylent Diesel
    Actually that sounds like a great idea too.
    Think about it eventually we are bound to run out of places to plant dead people and cremating them creates pollution anyways so might as well get to the store a few times with grandma AFTER she dies haha

    • Ketzer says:

      I wonder how long it will be before people realize that all the best remaining land, (the scenic parks, open areas, etc.) are full of carefully-preserved corpses in guaranteed-watertight coffins?

      Suddenly doesn’t seem like such a good idea, preserving our remains and giving each body 24 square feet of real estate until the second coming?

  16. monti says:

    I would go for Smart 0.8 diesel engine.
    65kg+clutch with good ecu remap(80hp).
    If lucky enough to find it in junkyard then it shouldnt be expensive.

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