Gas tank mount prototype

Discussion in 'Motorized Bicycle General Discussion' started by Cylon, Apr 10, 2016.

  1. Cylon

    Cylon Member

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    Hey guys, went to work on my bikes to day just doing regular maintenance tightening bolts, lubing etc. Then I noticed my new gas tank I just put on my bike cracked again even with the jb weld and seal all around the studs.

    So this time I went ahead and just made a prototype of a completely new mounting system. I have one tank left that isnt broken.

    I took a strong piece of plastic and shaped it like an I. I plan on drilling holes into the top bar on the frame and either bolting it if I go through both sides of the frame or I may just drill into the top side of the tube and just rivet it in. Im not sure yet. I will also be adding a 1/4,-1/2 inch rubber washer between the plastic mount and frame.

    No more stress on the studs. Hopefully problem solved.

    I only seem to have these tank problems with my Kent Glendale because it has a rounded top bar so to get it tight because of its pivot on the top bar I believe the vibration is stressing the steel studs and then causing the fractures in the steel. With the rubber and the plastic mount I think that the vibrations will be cut down a lot.

    Its pretty rough for now but I only spent 15 mins putting it together. I'll finish it later this week, it needs more trimming and paint.

    I went ahead and attached pictures.
    *BTW* Those are scratches from sandpaper not cracks.

    [​IMG]
    [​IMG]
    [​IMG]
     
    #1 Cylon, Apr 10, 2016
    Last edited: Apr 10, 2016
  2. allen standley

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    I hope that works for you cylon. It's never happened to me. Your pulling too tight or you are fed from a bad bunch of tanks I think. I use a soft handlebar grip under my tank and tighten nuts equally till the tank moves not. Then tighten no more.
     
  3. Cylon

    Cylon Member

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    Im about 95% sure its from the top bar being bent so it puts to much stress on the studs. The tank only sits on about 1 inch of the bar the rest of the support is coming from the studs.
     
  4. allen standley

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    yeah, that very well could be. Your fix should do it.
     
  5. Cylon

    Cylon Member

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    Finished the mount its not perfect but it seems to work for now will test it this weekend to see how it goes. The tank has a lot more movement, but is still sturdy.

    [​IMG]
    [​IMG]
     
  6. KCvale

    KCvale Active Member

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    Cool and all, but really not needed.
    Virtually all bikes have a curved top bar.

    If the studs fit around the bar all you do is prop the front and back up with foam or cut sections of grips until the middle part is above the bend, and tighten the tank down until the middle touches the tank.

    If your top tube is the right width but way taller than your tank studs reach, just use stand-off spacer nuts and new bolts to go up through the bracket to them like this.

    [​IMG]

    If your top tube is too fat to let the tank studs by, no biggie.

    What I do for that is a bit complex, but it works well...

    [​IMG]

    I have topics about this somewhere, but in short, I drill a hole in the tank brackets in the center, matching holes I Tap on the top of the tube, and mount the brackets the same way they face on the bottom on the top to the top bar.

    Do the usual foam/grip supporting of the front and rear of the tank and tighten it up.

    Whack off all the extra tank stud thread and you have a nice clean look to boot.

    NOTE!
    THIS NOT NOT IDEAL!
    Though the tank mounts to the 2 brackets in 4 spots, they don't have the natural support of the fame to bind to, it's just a taped hole and bolt for each one.

    For a street bike you don't wreck much it's fine, beating it up though and smash that tank around and it will fail.

    I have no problem with the extenders though, that is common enough.

    Personally, I am really into the new gas tank frames now, it's already a part of the bike.
     
  7. Cylon

    Cylon Member

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    I went for a ride today and my new mount is working great. Thanks KC for that idea, I'll do that next if I ever have the problem again, but how do you attach the bracket to the frame? Steel self-tapping screws?
     
  8. KCvale

    KCvale Active Member

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    No, a bit more complex, full details and parts/tools with pics needed to mount a gas tank to the top of the bar about half way down in this topic http://kcsbikes.com/topic.asp?TOPIC_ID=793
     

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