Please donate to the cause if you can, all funds will go towards the ongoing GX200 Eggmotor project. Thank you.


21 Responses to “Stuff”

  1. Mike Main Says:

    Your project is very interesting. Can you share the source, cost, original weight & power of the motor before modifications began? This will be helpful in appreciating how your mods have contributed to the project.

    Thank you,
    mike…in Los Angeles

  2. Hello Mike,

    I’ve only found Europe based sources of these larger than GX390 engines.

    This link is for a Germany based source for the 18ps engine (17hp GX440 variant):

    They also have the slightly smaller 16ps (15hp GX420):

    They also have an ebay shop too:

    The above links have detailed descriptions of original costs, weight and power figures.

    I hope this helps you Mike and thanks for your interest :o)



    • João Albano Says:

      I have a question, and also a sugestion.

      Well yeah with a GX 390/420 only usable on a trike never on a paramotor at lest what i believe not seeing being sotable for a +50kg paramotor on your back.

      The Gx200 are so good in my option why? around 15-17kg after removing fuel tank etc.. But one thing u must do upgrade the pistol/cilinder for 22mm remove the governer dont pass the 6500rpm, 6000 should be more then enough, higher then 6500 you will start “loosing life time on the motor”. You can easy get 16-20 also with a nice competition carb etc.. You should buy them easy and cheap in a kart store on anything like it, and if you explain what you want they will give you, not top quality but good and durable.

      4stroke engines last way longer then 2stroke.

      One mistake that i see happening is people since they are using 3000-4000rpm puting the porpule direct on the “flywhell” (believe that is the correct name english not my native language, like you notice), what this does is soonner or latter the “grip” on the flywheel and the blades will get loose, soon or later will happen… Puting the purpole direct there so you dont loose the “rpm” and you able to fly… and like this you paramotor wont last or at lest the grip..

      Gx200 is a motor able to stand alot of tuning remember that is a HONDA engine! Tuned put a reduction kit on it so the blade isnt directly put a small ractio like 1:2 and should be enough… Also starting my project and from what i read from a few project a see people not pushing the motor enough having to put the blade directly on the “flywhell” so they dont loose RPM and able to fly and take off.. Really look at Bailey Eggmotor they sell Kobra or Cyclone (rotation) and ANY 4stroke engine to see how much RPM they have its all about the RPM and on a 4stroke just put a silencer and the sound it does at 4000 = 6000 almost.

      You need a minion of “RPM” the blade need to do depending on if it’s a 2 or 3 blade. To take off considering 0 wind and depends on the height etc… So if the minium of RPM that a paramotor need to take off is the MAX of a 4stroke engine in stock… What you do? TUNE THAT FUCKER xD
      Remember around 6000RPM – never higher then 6500 it wont stress the motor believe even with factory stuff. And give a reduction so you dont put the blade attack to the flywhell just to much “pressour or whatever” when u gas up the motor and also when you stop gasing.. soon or later will get loose or “brake something”. Put just a reduction or 30-50% and since it’s a 4stroke and if you tune him a bit put a 3blade on the paramotor and you will see the power of a GX200.

      Of course if you plane if for a trake go for a 270 or 290 i think it should be enough.. Remember 390-420 start doing a bit of vibration. It’s a 4stroke working not a 2stroke. Remember that a 390-420 around what 30-40kg?

      Just giving a few sugestion and sorry for the long post

      • I have now sold the gx420 engine and now concentrating back on the gx200 project. My tuned gx200 engine still is direct driving the propeller. Have you seen my other blog?
        I estimate the gx200 is giving 16hp and +45kg thrust. I had it tuned to about 13hp before and got 40kg thrust. To get from 13hp to 16hp I have now fitted a gx390 carb and port/milled head. The engine already has .275″ cam, 18lb valve springs, ARC alloy flywheel, 8 degree timing key, ARC con rod, RLV exhaust, K&N style air filter.

  3. Hi, Rob!
    Are you going to spin up r.p.m., of the GX390/420 from 3600 to 5200 like on the GX200 by removing governer as well?
    Why so big gap between GX200 from 6.5 h.p to 15 h.p and just +5 h.p with the GX390/420?

    • Hello Stan,
      The governor has been removed but I don’t want to be hitting 5000rpm with the GX420. I reckon spinning a larger prop in the 3000-4000rpm region (Konig 2 blade) or 2300rpm region (3 blade fan) would be a more efficient use of power, less noisy and less stress on the engine. I could achieve 22hp probably at 5000rpm and through a reduction drive could prove very powerful but I’m happy if I can achieve +50kg thrust at lower rpm/less power and maintain a good degree of reliability :o) Maybe such a set up would be good for a trike option where weight of reduction drive isn’t a big issue???

      Regarding the power gap, the GX200 needs a minimum of 13hp to give enough thrust from a small inefficient prop but because the GX420 can give similar power but at a lower rpm (3600rpm as oppose to +5000rpm) then additional modifications can be minimal. For instance, 14hp @ 5200rpm will give 40kg thrust with 34×10 prop where as 14hp @ 3600rpm will give over 45kg thrust with 42×15 prop. If you up the revs to 4000rpm with the 42×15 prop then up to 59kg thrust is attainable with 19hp.

      I hope this helps Stan :o)



  4. Rob, thanks for such extensive clarification. Just yesterday found your Egg`s))) website and see a very wide possibilities to be involved to paramotors… (never thought about this before but now…looking seriously).
    Is this engine will be fine for 15 h.p. reassembly?

    • Hello Stan, that is the very same engine I used 🙂

      Sometimes you can find them cheaper if you do a search on ebay. Try these different search criteria ‘6.5hp’ ‘honda gx’ ‘gx200’ ‘gx 200’ and you can usually find a cheaper one than the ‘pumpsuk’ offer.

      The Loncin 6.5hp will obviously need a host of parts fitted to get over the 14hp required for a decent enough power-plant. My website you’ve found hasn’t been updated recently but has a host of ideas. Tim Kerr at now does tuning kits and ready tuned genuine Honda GX200 engines suitable for the project (Stage 3 kit or engine required). Are you going for a direct drive set up or reduction drive for more thrust? Paul Bailey how has ‘Bailey-Egg’ kits available. Just search for ‘Bailey Aviation’ and find link for the ‘Egg’ page. His test machine is developing around 50kg thrust.

      Hope this helps.


  5. Thanks for the promt reapose, Rob!
    I just looked at Bailey`s website throuhgoutly and was unable to find any link to “Egg kits” at all… Have browsed every link in menu…
    I am 90 kGs (dressed up))) and direcr drive hope will be enough.

    Is your chassis drawings (on your Egg`s website) correct or need something else?

    Thanks, Stan

  6. Hello,
    I am a owner of Konig CRE/CS-430, and I’d like to build or buy a chassis that appears on the site. My Konig has a manual starter.
    Could you give me some suggestions?

    • Hello, the chassis I have designed and built is for the Honda GX390/420 4 stroke industrial engine that has been tuned to match the CRE/SC-430 engine power. That is why I use the same propeller. I’m sorry but the chassis will not fit Konig powerplant. Very sorry if my blog has caused you any confusion. Are you unable to source a genuine Konig chassis elsewhere? I don’t have any Konig engine dimensions to work with either.

  7. Hi Robert,
    I don’t have a Konig technical manual to use it to get the engine’s dimention.
    In any cases, could you tell me about the flex engine/silencer collector used for GX/390/420?

    Best Regards

  8. bonjour vous avez realiser quelque chose de magnifique je vous demande si je peut avoir les cotes du paramoteur pour reliser le meme merci

  9. I’m also into gx200 modifications

    It was only the cylinder head I couldn’t afford to replace

    But my propeller is coming off the engine shaft how do I attach it firmly??

    Pls any help??

  10. sir I have sent you a direct email

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