Here in Australia you can buy a 12 litre fuel bladder (from liquid containment), when it only has about 5 litres in it I strap mine to the tank but with it full I put on the rack and back part of the seat. The best part is that once it is empty you just roll it up and strap it to the rack.

It is a shame that a bolt on 25 litre isn't available, I wonder how many orders/inquiries safari would need before they seriously looked at making one.

http://www.safaritanks.com.au/home/a...ari-tanks.html

A mate has a yamaha WR450 with a 26L safari tank and he has no problems with fuel weeping (gee that as a concept sounds like it is leaking).

The only problem Jonno has with the WR is that it so uncomfortable on long trips and that by the time the tank his empty everyone has stopped to fill up anyway.