I know that some will slag this into the ground, so :f to you before i tell you how i get around this problem.
I have a windsceen washer pump from an Audi, any type would do.
This lives in the area under the tank next to your coolant bottle,
it's connected to an 8oz fuel tank as used in R/C model planes with 3 lines in it.
1, goes straight to the pump,
2, is the filler
3, is the fill over flow
I have a small press switch mounted on the flat section just forward of the clutch lever reservoir on the same casting within easy reach of your index finger to opperate the pump.
Running from the pump is micro line pipe ( thanks Scottoiler ) up to the clocks and onto a small bore brass pipe again model shop cost 75p this is glued to washer jet from a rear window from a Ford Fiest.
Spend a bit of time to set the jet direction then BINGO no matter how much %$fan comes you way its wash and go without any hassel.
I use screen wash, the anti-freeze type you know what the weathres like up here even mid summer.
"GREAT IN THE SUMMER BUGGING OFF ON THE MOVE"