| part of the problem imo is that the tank is so flat (its under your backside) and low to keep a low c of g. - So with a flat tank the difference between full and not so full in terms of depth of petrol is very small and therefore not easy to measure. Petrol amount has never been easy to read on a bike given the lean etc. I have always had something reminder go off in my head at 120 miles that says fill up.
Forget the gauge go back to reserve tap? | 
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