Mythical Extra Litre?

[Invicta Moto]

Recently an R1100S riding buddy reckoned that by soem clever drilling around the fuel filler that you could squeeze in an extra (and usable) litre of fuel to the tank.... Myth or Truth?

Does it work on the GS1150?

 

[adamski49]

It allows you to use some of the air pocket trapped from the filler neck upwards, don't know if it's a litre though.

I'd have thought this wasn't really an issue on a GS with their hoooge tanks. The S has to make do with a measly 18l (4 gallons) which, if pushing it, gives a max distance of about 160 miles before panic sets in.

Proabably scrape the 200 mile mark in cruise mode but I wouldn't want to try it. In France I made 178m with a few litres left to spare but I was getting twitchy.

Adam

 

[Rob Farmer]

The fuel tank breather sits at the very top of the tank. If you drill holes right at the top of the tube and then fill completely up you end up with fuel coming out of the breather. Drilling holes further down the tube will mean that you cannot lean the bike over or use the sidestand untill you have used some of the fuel. I know some of the guys are running around with drilled tubes maybe they will comment. I tried it and got fed up with getting fuel all over the place; got a second hand tube and put it all back to standard.

 

[Rob Farmer]

Adam,

My mate got 210 out of his R1100ss, coming back through France, had him sweating though.

I was amazed at how much more economical the S is to the GS. Riding to Spain and back on everthing from peage to winding roads he consistently used 2 to 3 litres less than me in 150 mile jaunts. He is a skinny git though!

 

[adamski49]

Rob

210 !!! I'm impressed. I was with a ZZR 11 (high consumption but big tank) and a VFR (low consumption and big tank) both easily capable of 200 miles so I was the weakest link. I didn't realise the GS was less economical than the S - must be the strange areodynamics caused by the beak and height.

I shall never again tempt fate by seeing just how far I can get on a tank of fuel after running a 16V K100RS out of fuel on an autoroute in pouring rain at 2 in the morning and then having to push it 2 miles to the peage before geting lifts to and from the fuel station.

I think the combination of chipped up motronic, headwind, rain, full luggage, my mate as pillion and the three figure speed I was maintaining contributed to the fact that it ran out at 130miles I think this is called learning the hard way!

Adam

 

[Invicta Moto]

I managed to get 203.2 out of the GS1150 on the start of the National Rally and the warning light was on along the M4, then went out after the bike was tilted left and right on an exit. I managed to get about 17.5 litres in which is less than the reputed/claimed tank capacity.

As my handbook is in German (?) I have yet to find the spec for my bike.... 21 litres usable or not?

I asked about this mythical extra space as it was at that very stop when I was introduced to the idea....

 

[MikeO]

I've drilled the filler neck on my bike, but only to allow it to fill quicker - I still only cover the bottom of the funnel by about 5mm. The advantage is easy filling without any stop/go blowback, not extra capacity......

The mod is detailed here, along with some other mods.

Mike

 

[Rob Farmer]

Wish I was that sensible

 

[IainMac]

I've drilled my filler neck, aprox 1/2 way up at the front. Regularly get 20.5 litres in if I fill up to 5~10mm below hole, I usually fill up at around 10mile after the reserve light coming on.
Only downside. dont fill up b4 stopping for a while as the fuel will expand due to heat soak and piss out the tank breather.
Dealer's seen the mod as they had to replace the tank under warrenty (corrosion due to crap paint) and didnt comment either way.

Iain Mac

 

[Vern]

I drilled my neck (you know what I mean) about five years ago. First time I filled it up to the brim, petrol pissed out of the breather, thought about it for a bit, then fitted a little tap out of a wine making kit. Before I fill up, I close the little tap, I normally stop after 100miles or so, so all I do is open the tap. Any petrol that flowed into the breather tube, is sucked back into the tank by the vacume created by the used petrol. As for 200 miles on a tankfull, my old GS11 doesn't even put the light on untill 240 miles, and once that comes on, I can do a further 60miles untill dry. The record, 376miles (yes, really) when my other half was learning to ride, and I was riding about at 50/60 MPH.
Take bow, exit stage left

 

[David H Gutteridge]

Mythical Extra Litre

If you drill a hole in the top of the filler near to the rim you will get more fuel in.
However if you drop it then you will find that fuel will flow out from under the filler cap and all down your lovely tank.
It is better to do this with a tank bag on as it will absorb some of the spilt fuel and be a constant reminder of your foolishness.

Ah the sweet taste of bitter experience!!

David

 

[judge]

I drilled my neck...

and put a bolt through it?

 

[Vern]

Funny man, oops, there goes another rib

 

[philh]

I can see the discussion here is tank capacity but .........
200+ miles to a tank. How ?!
I can barely hit 140 before the low fuel light shines upon me.

Am I the only one ?


phil

 

[AdamZ]

Overfill

Careful that you don't overfill and the bloody stuff comes out over the tank damaging the paintwork.....

.... not covered unbder waranty and now with "piss" yellow stains on the tank, will have a respay at some piint...

I only manage 210-220 on the GSA tank