Atomic Zombie Motorized Tadpole Project

Discussion in 'Motorized Trikes' started by BentTooner, Jun 28, 2011.

  1. BentTooner

    BentTooner Member

    Hi, all
    I just bought the plans ($16.95) for a home built Atomic Zombie Warrior tadpole trike I plan to motorize.

    I currently ride a LWB Rans Tailwind recumbent and a SWB Rans Rocket recumbent that are motorized with a FD kit from BMP and a Robin EH035.

    I'm working on the Warrior's rear forks now and will post my progress and pix as I go. The plans were not as technical as I expected but are good so far.

    My first criticism of the plans is that there is no 'materials' list in them so I didn't know how much steel to buy.

    I bought three, 5' lengths of 1.5" square steel tubing with 0.065 wall thickness (16 gauge) for $2 per foot (total $30) at the local steel store. I bought more than I think I'll need in case I make mistakes.

    I'm using a Harbor Freight MIG 125 welder and doing the cutting with a cut-off wheel on an angle grinder.

    If anyone has any questions about the project or knows of any 'gotcha' mistakes or aspects of the Atomic Zombie plans, please let me know.


  2. Alaskavan

    Alaskavan New Member

    Should be an interesting project. Take, and post, lots of pics.
  3. srdavo

    srdavo Active Member

    I'm a big fan of Atomic Zombie.

    Looking forward to watching your build.
  4. BentTooner

    BentTooner Member


    I'm having some problems getting my computer to connect to my camera so pix are on hold right now.

    Briefly, I've built the rear fork legs and drop outs for the rear wheel and I'm working on the rear seat tube, front tube and center tube.

    Other than some annoying problems with the wire feed on my HF MIG welder, it's going fine. The plans are fine as long as you read carefully and go slowly.

    As soon as possible, I'll post pix.
  5. BentTooner

    BentTooner Member

    Pix of build

    I finally gave up on the camera and used my phone to get some pix to upload.

    They are attached. They show that I've finished the rear forks, rear drop outs, seat tube, center tube and front tube. No close ups because the phone doesn't do that well.

    I put a 26" mtn bike wheel in the drop outs just for fit and to hold it together and see how it looks.

    The next step requires that I cut a bottom bracket from an old bike. I will get a couple of donor bikes tomorrow and get back to work soon after that.

    If anyone has any questions, please feel free to let me know.

    Attached Files:

  6. srdavo

    srdavo Active Member

    Looking good!

    Thanks for the progress report. Keep 'em coming.
  7. BentTooner

    BentTooner Member

    Warrior tadpole update

    Hi, all

    I cut the crank out of an Murray Cruiser one-speed bike and cleaned it up and welded tabs to it so it can mount on the center boom of the AZ Warrior with pinch bolts, per the plans.

    Here's some pictures of the crank being primed and the crank and bearings, races, etc., which cleaned up very nicely. Not too exciting but might interest someone ...

    Since I've motorized my bikes, I no longer shift gears. I just put the derailleurs in a gear that is low enough for me to peddle from a dead stop to help save the clutch from wear. Other than that, I rarely peddle and I haven't shifted for 3 years. The derailleurs are pointless to me.

    So, I'm planning to use the crank from the Murray and the rear wheel from it with the coaster brake and single rear sprocket to see if that works for starts. If so, I won't need any derailleurs at all.

    I don't know if the coaster brake will be enough. If not, I'll put calipers on the front wheels.

    I ordered two BMX 20" wheels with 48 spokes and 14mm axles for the front wheels and am waiting on those. Cost was $80 with shipping. I couldn't find affordable wheels that were strong enough that offered disk brakes.

    The plans call for cutting up matching head tubes and making steering kingpins from them with extra hardware and fork stems and a very heavy mounting tab.

    I just met a guy who is building 2 trikes based on the 'Fleet Trike" web site's plans and he used the 'bushings and bolts' approach to kingpins detailed therein. I looked at his finished product and was very impressed with the simplicity and feel of the steering.

    So, I decided to make the "bushings and bolts" version of kingpins rather than cut up head tubes. I bought the bolts, bushings, washers, etc. but couldn't find the steel tube in the right sizes so I'm waiting on that. As soon as I get that, I'll build the kingpins and then go back to the AZ plans.

    While I'm waiting, I started on the seat, which is made from plywood. The plans don't specify the thickness of the plywood so I'm guessing on that.

    I'll post pictures and details on the kingpins as soon as I make them. That should be interesting...

    Attached Files:

  8. BentTooner

    BentTooner Member

    AZ Warrior Trike build update

    Hi, again
    Worked on the seat today.
    I've attached pictures to show how it looks with the rear wheel, seat and crank on.
    I need to find some rigid foam somewhere to cover the seat.
    Most of the time was in making the seat mounting tabs and then getting them welded in the right places on the frame.
    Still waiting on wheels and steel tubing.
    It's all probably pretty obvious at this point but if anyone has any questions, please let me know.

    Attached Files:

  9. BentTooner

    BentTooner Member

    Update on AZ Warrior Powered Trike build


    I got the Atomic Zombie Warrior trike on its wheels and I found the hardest part of the Warrior build so far... it's what they call the 'steering boom tubes.'

    I've attached some pictures.

    The problem is that the boom tube goes forward (at an angle) and also up (at an angle). This means you have a compound angle to figure out and cut on the first tube and then you have to MATCH it on the other side.

    The plans literally call for 'guesstimating' the angles and the cuts. It's a bear. Took me several tries, some swearing, sweating, a wooden jig and grinding off the tack welds on my first effort.

    I finally got it pretty close but it's still off a bit and it causes the rear tire/wheel to lean a little. I can fix most of it by shimming one of the kingpins with extra washers and adjusting the rear wheel in the drop outs.

    This is definitely a very weak spot on the design of this trike, IMHO. The reasoning for this bizarre steering boom tube design is in case you're short. Since the seat does not move, you adjust the crank on the center tube (as far as the chain tensioner might allow) and, if you have short legs, your heels could hit the steering boom tubes if they came out at a right angle from the frame where the wheels need to be.

    To get around this, they have the tubes come forward at an angle. Also, since the trike sits only 5" off the ground and the wheels are about 10" off the ground (20" wheels/tires), the tubes have to come UP to meet the kingpins.

    If I did not get the alignment correct after this latest effort, I was going to change the design and just come straight out from the center tube with a short beam and then up at whatever angle I needed to get the wheels vertical and true because I have long enough legs that the tubes would not have been a problem for me. But, luckily, I got it close enough on what was going to be my last try.

    I put some temporary foam I had laying around on the seat to get a feel for the crank location. I had some trouble finding a source for the foam. I think I have that solved now. Sourcing stuff is a problem.

    If anyone out there is considering the Warrior, please feel free to ask questions. It's pretty challenging...

    Attached Files:

  10. IbedaYank

    IbedaYank Member

  11. BentTooner

    BentTooner Member

    AZ forum


    Thanks. Yes, I've been on the AZ web site and forum a lot. Finding a local source for things is a problem and the forum isn't any help with that unless someone happens to live near you. So far, I haven't found that to be the case.

    Buying stuff on the internet takes time while you wait for shipping and you don't get to touch and feel the stuff to make sure it's really what you want. The seat foam is a good example of the problem.

    In the end, you have to make the cuts and welds yourself. This makes the Warrior a challenging build for a first-timer. That's why I mentioned it.

    I've been keeping a log of my build and will make a lengthy post on the AZ forum when I'm finished so a newbie Warrior builder will have everything I learned in ONE, complete post, rather than having to search around for bits and pieces.
  12. srdavo

    srdavo Active Member

    I am enjoying your progress...... thanks!!
  13. BentTooner

    BentTooner Member

    Seat Foam on Zombie Warrior Trike


    I bought some 2" thick rigid foam and cut it and glued it to the seat frame. I shaped it with a 120 grit sanding wheel on the grinder.

    I also finalized the steering boom tube welds and worked on all 3 wheels' bearings.

    The next step in the plans is the under seat steering (USS). The plans call for chopping down an old head tube and welding a goose neck on to hold handlebars and then welding a steering control tab on the head tube and connect a control rod to one wheel. The wheels will be connected by an adjustable tie rod, kinda like a car.

    I attached a couple of pictures to show the new seat foam.

    Attached Files:

  14. BentTooner

    BentTooner Member

    Warrior Steering

    Here's a pic of the completed steering system on the Warrior. I modified it from the plans which called for cutting down a head tube. The plan idea was a bit overkill to me for the job at hand. So, I used a square tube and brass bushings with a 1/2" bolt and lock nut for the pivot point. I welded a goose neck on the back side of the square tubing.
    I followed the plans as far as the lengths of arms and tabs and the angles recommended for proportional steering.
    The red circle is the steering tube.
    The green circle is the steering control arm tab on the left kingpin.
    The blue circle is the tie rod assembly.
    The white circle is where the goose neck welds to the steering tube.

    Attached Files:

  15. BentTooner

    BentTooner Member

    Warrior running


    I got the Warrior going today and took the first test ride out at the airport so it was flat and open. It did fine. It's fast and takes some getting used to in high speed turns.

    I'll do some fine tuning to a couple of things and then start adding the support system for the friction drive.

    Here's a link to a YouTube video of me riding it around the local airport:

    I've also attached a photo of my son riding it and you can see that you have to lean a lot when you turn at high speed.

    I've learned a lot on this project. I changed the plans in a couple of areas and I'm pleased with the changes.

    Attached Files:

  16. srdavo

    srdavo Active Member

    I enjoyed your videos. You look really comfortable & relaxed in the saddle.

    Nice work!
  17. BentTooner

    BentTooner Member


    Yes, it was very comfortable to ride. I really like having 3 wheels on the ground and not even thinking about balancing. I think it will be even nicer once it's motorized!
  18. BentTooner

    BentTooner Member

    BMP Friction Drive AZ Warrior Trike

    Hi, All

    I got the BMP FD engine mounted on the Atomic Zombie Warrior tadpole and it runs great!

    I don't have any issues with it that I'm aware of. Top speed seems to be about 25-28 MPH but I'm not sure since I haven't hooked up a bike computer yet.

    I also don't have any way to carry anything so I'll need to work on that.

    It runs straight and true and doesn't do anything weird at all. It's very relaxing to ride and requires almost no steering input on straights.

    I need to figure out where to put a mirror and then I'll take it all apart and paint it.

    Eventually, I plan to put a belt or chain drive on it.

    Attached Files:

  19. graucho

    graucho Active Member

    Hi fellow Zombie what an awesome job! It's the ultimate comfortable ride. I also ride with the RS engine but on mountain bikes, is it loud being directly behind your head? just curious.
  20. BentTooner

    BentTooner Member

    Hi, Graucho


    I normally ride a Rans Rocket recumbent with this same BMP FD set up and that also puts the engine pretty near your head.

    So, to me, the noise level is about the same as what I'm used to. That is the main drawback, though, and it helps that the RS engine is pretty quiet.

    I've worn ear plugs in the past and will probably end up doing that with the Warrior, too.

    For me, the seat (per the plans) is too narrow and I plan to add 'wings' to the bottom and/or back support for a little more comfort.

    Having 3 wheels on the ground is a big plus in ease of riding.
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