Aux Fuel Tank

[1948man]

Instead of using an aux tank, I use my regular tank as shown below. I have an extension on the vacuum line so it will be long enough with the tank moved back. Everything I have read on carb syncing calls for a gravity feed aux tank and the vacuum line plugged. Is it okay to leave the vacuum line plugged in like I have it for a carb sync? I guess I could plug the vacuum line and switch the petcock to Prime if that would better. Does it matter?

[7981GS]

What is holding the tank to the plywood?
Hard to see anything in the blur.

Daniel

[sedelen]

What is holding the tank to the plywood?
Hard to see anything in the blur.

Daniel

Looks like "gravity" to me.

[1948man]

The tank just sits on the plywood, but the plywood is bungied on both sides to keep it from tipping. Going back to the original question, is it okay to sync the carbs with the vacuum line hooked up to the tank?

[hampshirehog]

Yes. (now my reply is 10 letters long).

[1948man]

Gracias, darn that's only 8 letters. Gracias senior.

[7981GS]

The tank just sits on the plywood,

That is exactly what worries me!
So... what are you going to do WHEN the tank vibrates off and gets all dented up?

Daniel

[Octain]

The fuel source(whatever it may be) needs to be sitting close to where the tank would be if mounted. No vacuum. So the fuel shouldnt be going "up".

I use a gear oil bottle(or similar). The one with the pointy nipple and a long hose. Use a coat hanger to hang it from the cealing or the garage door rail.

[Steve]

That is exactly what worries me!
So... what are you going to do WHEN the tank vibrates off and gets all dented up?

Daniel

If your bike vibrates enough to move a gas tank that is sitting on plywood, you still have a bunch of work to do.

You can use a rubber mat or a rag between the plywood and tank to buffer any vibration, but all my bikes run smooth enough that a loose wrench barely moves, let alone a 20-pound tank.

1948man, the reason they say to plug the vacuum port is because most AUX tanks do not have vacuum-operated petcocks. The whole idea is that it needs to be connected to something (plug, screw, bolt, petcock, whatever) that does not allow air flow that would upset the mixture, there is no reason why your petcock would not satisfy that requirement. In fact, it is actually BETTER, because, when you stop the engine to make any adjustments, you will turn off your fuel flow, too.

The only thing that I would criticize about your setup is that the level of the tank might actually be a bit low. If your tank is empty enough to lift off the bike comfortably, it may not have enough "head height" to get the gas to the carbs properly. You might have to fill the tank a bit, making it a bit more awkward to lift off and put back on.

.

[pete]

I use an old whipper snipper fuel tank hung from a hook on one of the rafters in the garage, seems to work well:





My personal preference is to simply put the fuel tank aside after taking it off which reduces the chances of my clumsy self dropping it and denting it...

It's a bit higher than where the fuel tap sits on the tank, but it's as low as I can get it where I can still have a tap in line to turn the flow off.

[BassCliff]

Hi,

OK, here's my aux tank. Just a gear oil bottle, a little extra fuel line, a barbed connector, and I'm in business.



It's hanging on an IV stand. And you can see my golf tee in the vacuum line.


Thank you for your indulgence,

BassCliff

[1948man]

Thanks for all the suggestions. I will see about getting the tank a couple of inches higher. With the amount of reach in the fuel line, I should be able to do that. It's actually pretty full. There's no way it's going anywhere unless I or one of the mutts hit it pretty hard.

[Steve]

I'll show you my setup, but I would not recommend it, due to possible safety reasons.

I have drilled a hole in the cap of a gallon jug, put a piece of clear tubing through the hole that sort of forms a gasket, then slid a smaller piece of tubing into it to carry the fuel. Due to the need for frequent attention to the tubing joints to make sure they are not leaking, I can not recommend this for just anyone to use.





In practice, I find it rather easy to use. I fill it about half-way, which is more than plenty to do a sync job.


This also allows for a hand ON-OFF feature by simply turning the jug over.


Yeah, OK, the tank is usually OFF the bike when I do this, I just took the seat off to stage these pictures.

.