Fuel tank capacity

[John Armstrong]

Not wanting to push the bike and having almost emptied the tank on my 88 R100GS to change the throttle cables, I thought I'd see what the reserve capacity was.

I thought that the LH and RH taps gave about the same reserve range. And that is almost right. But and it's a big but, on my bike the LH tap has a reserve of 0.4 litres, or at the book figure for 90kph a range of 5 miles

But, if I don't have the LH one on, then the RH has a reserve of 3 litres till the fuel stops flowing. Switching on the LH tap to on gives another 3.25 litres. LH tap to reserve then gives the extra 0.4 litres.

So at 120 kph book figure of 40.9 mpg / 6.9 l/100 km I'd have:

27 miles on RH reserve, another 29 miles on the LH main, then pushing after another 4 miles. All assuming that I use the RH tap from the main, otherwise 4 or 5 miles later I'm pushing the bike. Reserve is quoted as "approx 4.7 litres".

BTW the manual doesn't seem to have anything about the above oh my god is this bike heavy or not after 5 miles.

 

[(RIP) Proff]

You have forgotten to factor in the most important point.
It's a non baffled tank and the fuel sloshes over the center rib.
Therefore running on just one taps reserve still uses a lot of the other side of the tanks reserve.....
I have both taps on, go on to reserve using rt tap go 30 miles splutter
then turn on left tap to reserve and go 6 miles and splutter stop

DAMHIK I was just very lucky to be within 100yds of Watford gap services when it did run bone dry, clutch in and rolled to within 50 yds of pumps and that was far enough to push a 90s

 

[John Armstrong]

So your figures for the 90 are similar to my guestimates.

At least if I run on the RH tap I might have about 10 times further to go than if I run on the LH tap

 

[(RIP) Proff]

So your figures for the 90 are similar to my guestimates.

At least if I run on the RH tap I might have about 10 times further to go than if I run on the LH tap

Nope, it'll just slosh to that side for 30 or so miles, then the 6 mile will it won't it gamble with lh tap

 

[John Armstrong]

Nope, it'll just slosh to that side for 30 or so miles, then the 6 mile will it won't it gamble with lh tap

Ferked whatever you do unless you're on a nice smooth motoway then

Anyway I think I'll run on the RH one and when it splutters, go onto the LH. Don't have to let go of the throttle then Unless I don't catch it soon enough and really need to pull the clutch in as the float bowls are completely empty

 

[(RIP) Proff]

I WAS on the M1 coming back from my mates in Cologne, Sun night should have stopped at Newport Pagnell but decided to try for Watford gap, got 245 miles out of that tankful, normally 200 from full to reserve

 

[John Armstrong]

I WAS on the M1 coming back from my mates in Cologne, Sun night should have stopped at Newport Pagnell but decided to try for Watford gap, got 245 miles out of that tankful, normally 200 from full to reserve

Had a Firestorm which liked to supp the fuel. Going up the M6 from Brum is quite good as the petrol stations are about every 12 to 15 miles up to Manchester

Worked out about 160 to 220 on mine if it goes by the book figures. Or 170 at 45mpg which seems to be a rough average for me and then another 60 miles.

 

[Sylvester]

Thanks Proff and John, useful stuff to know. My arse is normally the range limiter anyway but pushing a GS along the road is not on my list of things to do before I die. I remember my R80 having quite a big reserve range (possibly rose tinted specs) so I'll have to re calibrate for the GS and the fact I'm now in KMs.

 

[John Armstrong]

Slight update, after emptying the tank to find the reserve figures, I put in 5 litres. Rode to the garage 2 miles away and put in another 20 litres, so my maths reckons on a 25 litre tank.

BTW my tank has none of the anti splash faff of the later tanks and is not a PD one either. Something like: http://cgi.ebay.co.uk/ws/eBayISAPI....220344710085&_sacat=See-All-Categories&_fvi=1 but in white