1 An extra 1.5 litres in tank capacity. Mon May 14, 2012 5:39 pm
sidecar paul
Life time member
A couple of weeks ago, a K friend told me about raising the fuel cap to increase the tank capacity. He had seen the idea on an American forum.
I couldn't find any details and I can't find any reference to the idea on our site, so I looked at the fuel cap and came up with this scheme.
The alloy ring to which the cap fixes in the petrol tank is about 13mm thick. The fuel cap seal is about 7mm below this ring, so I figured that if I lifted the cap 8mm, I would be able to get a useful amount of extra petrol in the tank.
My 'lifting' ring is 116mm OD x 91mm ID x 8mm thick and I used a thick gasket between the ring and cap. The standard cap seal remains in place below the new ring.
Four new 20mm long M4 countersunk screws are needed.
Before fitting the ring, I had filled the petrol tank about 5 miles from home.
Assuming about 1/2 litre had been used in that 5 miles and I was able to get just under 2 litres in my 'new' tank, I can now get something like an extra 1.5 litres of fuel on board. (That's at least another £2 worth in the UK)
There is still quite a volume of expansion space remaining in the tank in case that sort of thing worries you.
Now it could mean a shorter walk if I run out of petrol..........or a longer walk because I went past the last filling station.
Paul.
I couldn't find any details and I can't find any reference to the idea on our site, so I looked at the fuel cap and came up with this scheme.
The alloy ring to which the cap fixes in the petrol tank is about 13mm thick. The fuel cap seal is about 7mm below this ring, so I figured that if I lifted the cap 8mm, I would be able to get a useful amount of extra petrol in the tank.
My 'lifting' ring is 116mm OD x 91mm ID x 8mm thick and I used a thick gasket between the ring and cap. The standard cap seal remains in place below the new ring.
Four new 20mm long M4 countersunk screws are needed.
Before fitting the ring, I had filled the petrol tank about 5 miles from home.
Assuming about 1/2 litre had been used in that 5 miles and I was able to get just under 2 litres in my 'new' tank, I can now get something like an extra 1.5 litres of fuel on board. (That's at least another £2 worth in the UK)
There is still quite a volume of expansion space remaining in the tank in case that sort of thing worries you.
Now it could mean a shorter walk if I run out of petrol..........or a longer walk because I went past the last filling station.
Paul.
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'84 K100RS (0014643) (owned since '85), 86 K100RS (0018891) with Martello sidecar (built as an outfit in '88),
'51 Vincent (since '67),'72 Montesa Cota (from new), '87 Honda RS125R NF4 (bought 2015)
....No CARS never ever!