Gas tank placement advice?

Given my choice, I'd really rather put my tank on the downtube. Mostly because I just don't want a gas tank, or anything else, in my face while riding.

I can get it in the spot I want. And it looks okay. It needs to be tilted toward the right to clear the top tube. Tilted left is not good. Gets awfully close to the exhaust.

I'll lose a bit of tank capacity because of the angle involved. Looking at it I'm guessing it'll hold about 3/4 what it would on the top tube. I can live with that. The outlet is just about perfectly level with the fuel intake inlet port. So there'll be just a little bit of the bottom of the tank that will be too low for fuel to flow out. Very little. And that's okay, too. It'll make a sediment trap, if nothing else.

But now I've got to figure out what to do with my CDI. The first thing I tried was moving it down to where it's just in front of the cylinder. Not too bad, maybe. It'll be fairly well protected from weather and road splash. But it's pretty close to the cylinder and the exhaust. I'm wondering if heat could be a problem?



Or I could mount it directly underneath the gas tank. It'll be more or less in the standard spot. It'll have its 'head' pointed downward, though. Definitely exposed to the elements. But I guess I could come up with a cover of some sort.



The simplest thing would be to mount the tank over the rear wheel. But I just don't really like the look of that.



So I'm inclined to go with the CDI under the gas tank. But I'm wondering if anyone has any other ideas. Also, am I missing something? Are there any dangers to the equipment here that I'm not taking into account?

Thanks.

 

[Timbone]

How about two steel cylinders, each holding about a liter of fuel, placed side by side under your top tube?

 

[bluegoatwoods]

That actually does sound pretty cool, Timbone.

I would gladly consider non-standard tanks. But I probably won't look into it too much. I don't want to increase expense or build time by very much.

But your suggestion has already got me thinking about something.......

A few of the vendors on this site carry tanks that are made to be placed under a rear rack. Maybe one of them could be mounted on my downtube.

And it might end up looking something like what you've suggested.

Maybe it's worth investigating.

Thanks.

 

[Gobisox]

Hey Blue,

I actually did what Timbone had suggested with the two cylinders. Worked well but was concerned about having a decent drop for gravity feeding the carb.

 

[bluegoatwoods]

Very nice looking bike you've got there, Gobisox.

But it doesn't look like you've got any trouble on the elevation issue. You ought to have plenty of fuel flow.

If I went with something like that, I think I'd have to be worried. On my bike the outlet would be awfully low. Looks like roughly as low as what I'm likely to end up with right now.

 

[darwin]

Put the fuel tank in your basket and run a flexible hose to carb, route it with slack for turning though...............that frame is the worst for a motor kit by its design. What kind of hub is that on the front wheel? Blue don't take this the wrong way but what were you thinking when mounting that basket and front fender? Looks like Picasso put it together, but hey it works right?

 

[darwin]

http://peoria.craigslist.org/bik/4737684313.html

 

[Gobisox]

Thanks Blue. There are several things I'm looking to improve but i like the start so far. Got to live up to Grandpa's motoring goggles.

Despite where the tanks are mounted, the key was the fuel line itself. I originally had a strait run from the tanks to the carb and had problems with consistent flow. There was a defined grade down to the carb but it didnt matter. Rerouting the fuel line with an almost vertical drop, then rise, solved the problem. I understand that there will always be subtleties that create problems when dealing with "hand crafted" parts, that may not apply to your situation, but I thought I'd offer what worked for me.

 

[bluegoatwoods]

...... Blue don't take this the wrong way but what were you thinking when mounting that basket and front fender? Looks like Picasso put it together, but hey it works right?

I know. Baskets aren't exactly popular in our set. And I can see why; they take away from the 'look'.

But to me a bicycle must, must be able to carry a good deal of stuff. The basket plus those struts I added down by the axle form a frame that allows me to hang backpacks on either side. Something like panniers. But more easily removable and replaceable. The basket itself doesn't carry much. Delicate items. A loaf of bread, for instance. Or my jacket or hat when I'm starting to get too warm. Quick and easy.

 

[darwin]

Here's a tank that fits under the top tube with an offset filler, might work for ya Blue. http://www.gasbike.net/bike-motor-parts-long-oil-tank-gasoline-tank-black.html