Columbia 1937 board tracker real gas tank

I normally don't build on ~$150 wally world type bikes but this caught my eye.
http://www.walmart.com/ip/39801995?...7321352&wl4=&wl5=pla&wl6=105949407872&veh=sem

The 'tank' is two pieces of pressed formed sheet metal that butt together in the middle via 2 struts attached to the frame via cut outs, two screws on each side plate, and top mounting hole to strut between the split top bar.

I thought I'd see if I can make it wide enough to get a filler and petcock on it and seal it up like Sportsman does.

I made new inner struts to widen the front 7cm wider and the rear 3.5cm wider.
NOTE: flattening the front struts V mount out straight gives you the back strut.

That leaves me enough room for the petcock, and with the wider front enough room for the filler I hacked off an old kit tank.

I found a spiffy thinner steel filler and venting cap that that is pretty darn cool.
If the bike falls over all you get is a little drip from the tiny vent hole as the cap is threaded with an O ring seal.
http://www.ebay.com/itm/Custom-Fuel...h-weld-in-Bung-SMALL-CUSTOM-NEW-/191495380281


For the petcock I'm going with the new MB kit one with the threaded collar so you can orient the valve lever and it has a double long inner screen with a Normal and Reserve setting.
http://www.gasbike.net/gasoline-tank-switch-for-2.5-L-gas-tank.html

Reserve on this flat tank should be enough for 10 miles or more.

I got some poster board to cut out the templates for the sheet metal and thinking I'll just pop-rivet it on because I found this to seal up the tank.
http://www.caswellplating.com/restoration-aids/epoxy-gas-tank-sealer.html

A gas-proof liquid 2 part epoxy that creates a solid tank inside the shell.

Under $100 to NOT use a peanut tank is worth it, and the bike itself has potential for handlebars down board tracker feel or sit up nice beach cruiser.
Worth exploring for me ;-}

 

[Wolfshoes]

This looks great. If the goal is to make a bike worth more than it cost to build, which seems harder to do than it sounds, you could be there. You are the best there is. Please forgive me for bringing it up but I hope you take your own advice and give this tank sealant system a good long vibration test before you release it to a customer. It looks so good making it painful to sell used, but it may be worth it.

 

[KCvale]

This looks great.
If the goal is to make a bike worth more than it cost to build, which seems harder to do than it sounds, you could be there.

Indeed that is the goal.
An actual big working gas tank in the frame is the coveted tit's on an MB.

The frame is pretty solid, nice thick steel, the rack is removable not part of the frame.
And it has 3-piece cranks ;-}

It has to be a 2-stroke, 4 won't fit (bummer) but with a shift kit and 3-speed back wheel quote a cool ride that will actually go well over 100 miles on a tank of gas, especially if you put the bars down like a board tracker to get aerodynamic.

Give this tank sealant system a good long vibration test before you release it to a customer.

I will be double checking everything.
I sell locally and inform my customers about everything, if this first tank leaks I want to know and I'll make it right for free.

 

[Sgt. Howard]

Bloody damn awsome!

 

[KCvale]

I have my sheet metal templates cut out and test fit.
I did it with just 2 pieces.

This is a shot inside from the bottom with top piece on so you can see the 2 struts.

The back strut is the original front strut flatted out.
The silver front one is mine.

The struts give the sides some structure and fills the 4 side holes with a bolt and cover.

Both pieces have at least a 10cm lap everywhere.
This the top.

And the bottom piece.

(cont...)

 

[PocketBiker]

KC,

Thank you for telling me about your build site. You have really inspired me! Man, if you seal up that planned expanded tank, you will have fantastic range! Seems like it would be well over 2 gallons? I'm still kind of stuck on a fiberglass inner tank.. leaving room at the front and/or rear for oil bottles, tools etc. So, I will be tossing around the best way of opening one side, giving me access to fill the tank, oil etc. But, the sealer idea is really something!

And that fuel petcock with a reserve position! Really great for such a large tankl!

For a budget, I found this alum./steel cap assembly. The cap Dia. is only 1 5/8" and the knurled edge looks nice only $13 delivered. Not sure, you might have to drill a vent hole?

http://www.ebay.com/itm/DOM-Steel-W...5&pid=100005&rk=3&rkt=6&sd=221428977021&rt=nc

 

[KCvale]

(...cont)

It looks like it belongs there to me.

I even kinda dig the top white accent but we'll see.

Note the filler tube and cap I have sitting on the tank won't be used, it is an example of what to expect if you want to cut your stock engine kits tank up for parts.

All I could get was ~2/3" of filler neck which puts the 2 1/8" cap right next to the top bar. No way to get grip around it.
You would need to make front ~3/4" wider and it would work.

The filler I have coming will fit pretty in that spot and be easy to operate and gas up.
The petcock fitting is not going well, Cole is out fetching parts and is dropping my mock-up off at Jim's to have a look at it but the 1st hardware store didn't have a tread match for it.

In the mean time the bike is being fitted with front and rear C-brakes with a dual pull brake lever for a 3 brake system, it's not a light bike and with over a gallon of fuel on board harder than most to stop.

And mounting the engine...
It is tighter than it looks.

I have a couple shots of it in handlebar Board Tracker look I'll post later, not ideal handlebars.

 

[james65]

Thank you for this great thread.

 

[KCvale]

KC,

Thank you for telling me about your build site. You have really inspired me!
Man, if you seal up that planned expanded tank, you will have fantastic range!
Seems like it would be well over 2 gallons?

My pleasure PocketBiker, just sharing what I'm trying.
I don't know how much larger than a full gallon it will end up, but enough bigger that you could pull up to a pump, put exactly 1 gallon in, and then just add 4oz (1/2 cup) of 2-stroke oil on the spot.

I'm still kind of stuck on a fiberglass inner tank.. leaving room at the front and/or rear for oil bottles, tools etc. So, I will be tossing around the best way of opening one side, giving me access to fill the tank, oil etc. But, the sealer idea is really something!

Using the area for storage is certainly possible if you make it big enough, but I'm going all gas.

I went with this $40 3 part Caswell epoxy tank kit
http://www.caswellplating.com/resto...oxy-gas-tank-sealer-mini-kit-up-to-5-gal.html
With shipping in was $57.

Properly done it should make a nice completely self contained solid inner tank, struts and all.
I was even thinking of maybe even putting a couple of big vertical fins on the struts to reduce the amount of 'fuel slosh' one might get with a long flat tank carrying that much fuel in stop and go traffic but I may be too late.

I stopped by the metal shop around the corner and he said he had material for my templates and could button it up nice for $100.
That includes putting in the petcock and filler bungs.
He didn't know about that epoxy tank sealer stuff, that makes his job much easier, it don't have to be air tight.

And that fuel petcock with a reserve position! Really great for such a large tankl!

For a budget, I found this alum./steel cap assembly. The cap Dia. is only 1 5/8" and the knurled edge looks nice only $13 delivered. Not sure, you might have to drill a vent hole?

View attachment 56088

If the filler is the steel part that will work, and the price is right, but it's close to the tank and yes, just a little hole in the top.
I went with a longer filler (1.5"x1.5") and steel venting cap 1 3/8").
$30.

You have 2 top bars so it's still pretty wide up in the front and you to be able to grip the gas cap, besides, I like a long filler neck to avoid spilling gas.

I want to use this MB kit petcock with reserve but finding the right size pipe thread is proving difficult so far, but I'm not going to sacrifice a new tank for it.

Standing straight up in that long flat tank it should have a dozen miles or more of reserve and room in the tank for exactly 1 gallon of new fuel.
Ride until you hit reserve, drop another gallon in at the pump, easy ;-}

 

[KCvale]

Even a 2-stroke is a tight fit.
You'll need an offset Z intake.

The engine will go down to within a few mills of the chain guard for a bit more room but it's still going to a pretty short fuel line, possibly not enough for a fuel filter.
The throttle cable may be problematic as well unless I can run it to the front between the split top bar.

This what it looks like with the handlebars down.

Not my style but there it is.