Using you frame as a gas tank ( Nirve Switchblade Chopper )

Discussion in '2-Stroke Engines' started by Blaze, Oct 4, 2007.

  1. Blaze

    Blaze Guest

    I get a lot of questions about how I converted my top frame tube into a gas tank. This should apply to other bikes as well. I wrote this kind of fast, and it's not exactly in the right order, but here is everything you need to know:

    Basically, you have to seal the front and back of the top tube with some sort of temporary sealant, then pour in some fuel-proof epoxy to permanently seal the tube. Use 45 minute 2-part epoxy from a hobby shop that is sold to build gas powered model airplanes. I sealed mine 2 years ago and it's still solid.

    First, you need to drill and tap a hole in the bottom of the rear side of the tube so you can install the fuel tap there. Make sure you clean out the tube really well before installing the fuel tap and brake bleeders. You don't want to have any metal shavings swishing around the tank. I just swished around some alcohol in the tank a couple times to rinse it out. As a backup, you need to install a fuel filter in your fuel line to make sure nothing nasty gets into your carb.You can see on my bike where the tap is going to the carb. Next, at the top front of the tube, you have to drill and tap two holes, one in front of the other, and install small brake bleeder taps from an auto parts store. The front tap will be used as a vent and the rear tap will be for refueling. Get a couple of the rubber covers for the brake bleeders. They really only last maybe 6 months or so if you're lucky, but the only thing they are used for here is a fuel cap, so replacing them from time to time is no big deal. While you are at the auto store, pick up a small section of auto fuel line (one that fits tightly over the brake bleeders), a small funnel (one that the fuel line fits into tightly), and a few feet of small clear tubing. You will take a short section of the fuel line and stick it into the end of the funnel. This is how you will refuel the bike. Pop the funnel/fuel line over the rear brake bleeder, and it should be stiff enough to stand up on it's own. Now just pour your fuel into the funnel. As for the clear tubing, it will go over the front brake bleeder. Drill a small hole into the left plastic fork cover and run the other end of the tubing about a foot into the fork. This is to vent the tank and prevent the vent from spilling any fuel. If any fuel spills, it will just run out through the bottom of the left fork.

    Now you seal it. After drilling the holes and cleaning the tank, this is really the next step before installing anything, so these directions are a little out of order.

    For the front of the tube, you can just remove the forks and put a piece of tape over the vent hole. For the back of the tube, it's a little harder. I finally ended up succeeding by using expanding foam from a hardware store, and very carefully shooting a little bit into the back vent hole to seal it. The foam will be shot through the hole you drilled for the fuel tap. It's hard to see the vent hole to shoot in into, but if you get in there real close with a flashlight, you should be able to manage. These two methods are just to seal it well enough to keep the epoxy from leaking out while it cures. The gas will eat right through the expanding foam, so it's only good for holding the epoxy in place.

    Prop the bike up, or hang it, so the back end is pointing straight up. Mix some epoxy and pour the epoxy in though the front hole until it's filled up within about 1/4 inch of the hole. Let it hang there until the epoxy cures. Now hang the bike so the front is pointing up and do the same thing for the fuel tap hole. Let that cure. Install your brake bleeders and fuel tap, and you should be ready to go. Fill it with some alcohol to test it. If it leaks, you may have to add a little more epoxy to try to seal it. If you have to add epoxy, this time pour in the epoxy and move the bike around to get the epoxy to coat up the sides of the tube a bit, then let it cure.

    It's a lot of work, but it looks really cool in the end. I get a lot of questions about this bike, but the biggest one is "where is the gas tank?"
     

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  2. Fatboy

    Fatboy Guest

    My Switchblade project and You are the Man

    Blaze,

    I was needing that exact info. The bike is so clean I can't find a clean way to put a gas tank on, that I am happy with and was wondering if it was possible to use the frame. YES. Thank you for the instructions. I am planning on using a motor mount for a Stingray I bought off Ebay for the motor on a fabricated crossmember placed level with the stock chain guard. I also got one of the guys drag pipes. Nice! Now to find some resources here in Iraq in my off time and get some more work done. As you can see I am just starting. The bike shop had to send it in pieces to get it here through the US postal system to Iraq. Needless to say I had to build the bike first but am waxing all the parts with S100 Carnauba as it goes together. Added protection in these harsh elements and lots of dust.

    What is the capacity of the frame tank? Are there any other alternatives to the brake bleeder system you can think of after your build? I was wondering if a small boat bilge plug would work or cool bottle stopper.

    I wish I had known about the spokes ahead of time. I would have had the bike shop in the States mod the wheels for me before shipping.

    Great Info! Thanks for your time posting it and the pics:grin:

    John
     

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