Trip computers, full of shit on any vehicle. Take your own real-world stats in terms of km's travelled per tank.

Generally was pretty accurate, I ran to fumes with 15ks flashing.

But mine has just started going weird at ~5000Ks on the bike, now shows 400+ km when full and only goes down to 100 when empty.

I was reading in a US cruiser mag that listed all 2010 HD softails have a new fuel sender as a change (in addition to the helical 5th gear). Seems there could be a problem with the sender, will check out with my dealer, might be a warranty claim....

I have the led fuel cap which is OK but knowing your ks/tank using the trip meter is still the best method.

Thats the way. And 300kms sounds right. I'm on a 1200 so we have the 4.5 gallon tank. Conservatively, will give it a drink every 250km/h.

Hey Guyz

All good advice and considerations / suggestions. 

I don't have a fuel gauge of any kind on mine, but i have worked out roughly how far it will go etc and work my fuel stops around that.