Fuel filler neck

[thebiker]

Hi

I am sure I read in a magazine that you could remove the fuel filler neck and drill some holes in it to allow more fuel into the tank and maximise the capacity of the tank.

Has anyone tried this?

 

[Gatesy]

Yes on my last 04 GS. It did enable a bit more fuel in and speeded up filling, however the risk of getting swarf into the tank probably outweighs the benefits. Didn't bother on the 07 model just shortened the plastic insert thingy by about 3 cms.

 

[Stahlgewittern]

neck

Took filler neck out drilled 3, 4mm holes.
Much faster filling which is the best benefit, also squeeze a bit more fuel in.

 

[GB.]

Someone recommended it to me while I was filling up at the garage last week, said he had done his 05 GS, gets another 2 or 3 litres in it and it fills quicker, said it uses the expansion part of the tank for when it gets hot, is this correct?

 

[Rusty Bolts]

I did it to mine about 1 month ago. Yes you can get more fuel in and yes it does speed up filling. Be aware that although you do get more fuel in it the area you are filling up is what would be used to allow the fuel to expand. And if you fill up your bike just before getting home then put your bike away expect to find a puddle of fuel on the floor. Also if you fill up just before you arrive at work and park your bike in full sun so all can admire it's Tutonic splendor that it will deposit a puddle of fuel on the floor with the obvious fire risk as most University Students are sometimes educated well beyond their intelligence and are likely to throw a fag butt near your pride and joy.
As far as swarf goes I used several magnets as well as rags etc to collect the swarf.

 

[(RIP) Miff]

I too have done this mod on my 05 1200gs. I can get MORE than 20 litres in my 20 litre tank. I only generally do this when touring and the extra smidgeon of fuel would be useful.

removed plastic neck thingy. Drilled 1 x 4mm hole in metal neck.

 

[JPB]

This was one of the first mods I did on my '04 GS about five years ago. I'm sure I took the following description of the mod from elsewhere on this fine site...

"FUEL FILLER NECK MOD

Has anyone else experienced difficulty filling the fuel tank, given that the rubber insert at the bottom of the filler neck (not evident on previous BMW's I've owned) is a nice snug fit around the pump nozzle.

This means the filler nozzle forms a nice seal and doesn't allow the tank to expel air efficiently as it fills with fuel.

This in turn creates a fairly large air pocket at the very top of the asymmetrically shaped plastic tank, which I would much rather held fuel.

To my way of thinking there's no point having a petrol tank that allegedly holds 20 litres when you can only ever get 18 litres in.........

So, I decided to mod the filler neck, just as I've done on the previous BMW's I've had......

After removing the shiny bits and stuffing rags down & around the metal filler neck assembly, I drilled three small (3mm) holes near the upper lip (shown in the pic. below) and then reassembled the whole thing.

A quick visit to the petrol station proved the exercise a success in that there was no coughing & spluttering petrol all over the bike and I could actually hear air expelling from the holes.

I also managed to get 21.5 litres of petrol in a tank previously drained to within about half a litre of being dry....

I'd like to think that this may have extended the range to about 230 miles, which is similar to my 1150RT, especially useful where petrol stations are few & far between..........?

Remove both side panels, via dzus fasteners & plastic quarter turn fastener inside, by forks.

Undo the six filler cap screws (if you open the filler cap & stuff clean rag in you'll stop metal swarf from entering the fuel tank or accidentally dropping a screw in!).....

Then undo two screws near the beak & two which hold the bottom of the the metal panels to the fuel tank and the whole painted tank top & metal side panels come off as one.

I then wrapped another piece of rag under the metal filler neck flange which now has about 2cm movement, restricted by internal plumbing. This rag is again to stop drilling swarf from entering the tank.

Then drill the holes & reassemble.

Clearly this whole exercise is unecessary if you don't mind waiting ages at petrol stations for it to cough & splutter fuel everywhere while you fill it to about 90% of it's capacity..........besides it was pissing down with rain here today & I didn't have anything better to do!!

Excellent - thanks for that. I'm a bit worried about drilling into some important pipe or something. Anyone know if there's any pipes that are in the way?

In the meantime, the rubber neck can be removed by slipping a finger inside the hole (!) down through the rubber bit and then gently prising it upwards. It comes off with ease.

It doesn't solve the air exit problem unfortunately - that will need the hole method, but it should prevent fuel spurting all over the place."

 

[RichieS]

Fuel filler neck Mod

I did this on my '06. Has anyone done it on an '08> model? Think the neck may be slightly different

 

[Dainese Brave]

I did this on my '06. Has anyone done it on an '08> model? Think the neck may be slightly different

The 2010 model (Gsa) is definately different...I guess a refinement to improve the irratic filling, which it does.

 

[Snow White]

I've done it to my 06 bike. as everyone said, big improvement. I found it really helped when touring.

Despite absolutely filling it to the brim I've never the excess going down the overflow pipe, but then if i know I'm going to be leaving it in the sun I would probable leave a bit of a gap.

When i did it, I also used a couple of magnets to catch the swarf, worked well.

Highly recommended mod

 

[EggChaser]

The later models have a breather up the side of the plastic neck so can be filled above the lower lip of the neck so do not need the mod.

Also - don;t do this on a hot day unless you are riding somewhere immediately as expanding fuel will come out of one of the overflows.

 

[thebiker]

Drilled two holes this morning so when I go out tomorrow will report back.

 

[snerkler]

If you're having trouble getting enough fuel in buy a GSA

On a serious note the tank is designed to leave a bit of space for a reason

 

[JJH]

I did the job on my 06 12rt and its worthwile seeing that its for free 29 liters and 540 kms to empty. About 340 miles. I had a 09 gsa and the filler has been altered to plastic but not as deep into the tank and it would take 36 liters to fill. The first time I filled it i thought that the garage had done something but it took 36 liters in a few different places. I had a 800 st which often took 17.5liters thats sabost to be 16. The empty space is to allow for expanison but who fills up and dosent ride further unless you work in a filling station. I know people say that you dont need the extra capisity but I say its handy not to have to stop every few days to fill up when commuteing. Look at Hondas new vfr 1200 about the only critisim is range.