Vent the Gas Tank Filler Neck

If you are tired of not being able to completely fill the gas tank and having the bubbling air escaping from the tank blow gas all over the tank top, you can solve this by adding a few air vent holes to the tank filler neck. I had to put 4 fairly good sized holes in the front and right side. The process is simple - just use a punch awl and ball-peen hammer to make the holes, as shown in the picture.

Here are a few more tips:

NEVER NEVER NEVER drill! Not only will that dump metal shavings into the tank, but all electric drill motors create sparks!

When you use a punch awl, just put the tip in contact with the filler neck and hit it enough times to make the hole as large as the awl shank (not just a little hole from the tip). You will need a MINIMUM for four large holes to make a big difference. I have seen a suggestion to use wax paper between the awl and the tank neck to reduce the chance of sparks - no idea if that provides any value at all, but it can't hurt. I personally think there is no real risk of sparks from using this method. I also suggest putting a thick towel or something over the tank near the awl head so you do not accidentally slip and mar the tank with the hammer.

A dead blow hammer would be an excellent choice for this job - less chance of slippage, and they are all covered in plastic.

Several folks have said to do this with a full tank - I disagree. If it is too full, the vibrations from the hammer blows will splash gas all over you. If you have to do it with a full tank, place a rag over the opening. I think that any level below the filler neck is probably OK.

And some important information about filling your tank AFTER you do this mod: You now have a CHOICE how full to make it, and that choice is important. If you fill it all the way to the top and then park it in the sun while you go have lunch, the heat will cause the fuel to expand and run out the overflow hose into a big puddle under the bike! Even just the engine heat can cause this, so my recommendation is simple - if you are going to ride at least 10 miles right after filling it up, put as much in as you want. But if you are just around the corner from home, or planning to take a break before getting back on the road, either wait to gas up until after the break, or keep the fuel level down near the bottom of the filler neck.

Great Idea!

Question though...did you completely drain the tank prior to punching the holes or did you use some spark resistant tools? [or just got lucky?]

Ron

I thought of possibly drilling mine out!! :rotf:

Do it with a nearly full tank. Fuel burns, vapors explode. a full tank won't explode, it may catch fire but then you just put the cap on. If there was a spark. Then again you could use a deadblow hammer. Mine is covered in plastic.

Yes, do it with a full tank of gas, then there's no room in the tank for vapors and liquid gasoline doesn't burn. Make your punch super sharp too, then it won't slip and possibly make sparks when you hit it with the hammer. Quite a bit more gas will fit in the tank and you get several more miles out of a tank of gas.

Yeah...had quite the conversation with the boys last night at the fire hall about this one. suggestions where:

* drill it.

* Fill it up completely with gas.

* drain it and vent it with an air line until clean and dry.

* fill it with water.

* and my personal favorite for creativity: hook a hose up to the exhaust of the nearest running motor and use it to fill the tank with Dioxide [Monoxide?] fumes...forcing the oxygen and or gas vapors out of the tank, making the fuel mixure to lean to burn/explode.

As always...thanks to all. I truly enjoy this site.

Ron

Yeah...had quite the conversation with the boys last night at the fire hall about this one. suggestions where:

 

* drill it.

* Fill it up completely with gas.

* drain it and vent it with an air line until clean and dry.

* fill it with water.

 

* and my personal favorite for creativity: hook a hose up to the exhaust of the nearest running motor and use it to fill the tank with Dioxide [Monoxide?] fumes...forcing the oxygen and or gas vapors out of the tank, making the fuel mixure to lean to burn/explode.

 

 

As always...thanks to all. I truly enjoy this site.

 

 

Ron

One other option is to use welding gases. If you have access to MIG or TIG welding gases you could fill the tank with an intert gas mixture such as CO2, 75%CO2/25%Argon, or pure Argon. The Argon is heavier than air and would stay in the tank, preventing combustion should a spark be generated.

You can also use a hose connected to an exhaust from another veichle pointed at the top of the tank where you will be working . With the carbon monoxide present and no oxygen , the element of spark will be null . I have seen welders weld up fuel tanks with fuel within this way when I worked as a heavy equipment operator and also when I was a roughneck in the oil feild .

gene

Note........When your tank is vented in this manner and you fill it to the top in the summer when it is hot and the engine is hot........then put it on the sidestand you will find a puddle of fresh gas under your bike in about 5 minutes.....Therefore fill up after your break at the gas station and ride at least 15 miles after a fill-up..You will get a lot more gas in after venting......3/10 to almost 4/10 of a gallon

Well, as part of my winter to do's Part-1, was to vent the filler neck.

I drained the tank completely (the best that I could) and let her vent for a week [it snowed so i was in no hurry]. Got out the trusty scratch awl and started 'wackin'. Eight holes later, followed by one minor Air box mod, the attempted lowering of the front end [failed/chickened out] and then the reinstallation of everything.

Out come...thumbs up. it appears to be much easier to fill the tank up. the sudden over filling of the filler tube no longer appears to be an issue.

So, I would recommend this mod to all! (just don't blow yourself up in the process)

Enjoy