I think water flows into my gas tank. Every time i keep my bike out in the rain this happens, runs good for the 1st 0.5km then starts missing for around 3km-5km, also the rev rate has to be over (Rpm 1600+) if not the bike stalls. After round 5 km its all good runs smooth. This is a big issue when stuck in traffic. Any solutions?

Thanks

 

Keep an Allen wrench handy and drain a tablespoon out of the carb bowl. This may help identify if its water in the fuel.
Snowmobile riders use a device in the tank to soak up water.
Do some leak testing.

 

under the gas cap there is a hole, or two cant remember
Im guessing one or both are vent holes
is there a chance your not vented properly
or you gas cap isnt making a good seal and water gets into the tank

maybe tape plastic over the gas cap for a week and see how many times that problem happens

if it still does then maybe its a venting issue

there are additives you can put in the tank to get rid of the water too

 

Are you sure it's not an electrical issue? Sounds to me like water is getting somewhere it shouldn't, but probably not in the tank??? Try spraying water on all electrical areas from a spray bottle to see if you can re-produce the issue. And does if it goes away when warmed up maybe the water is evaporating from engine heat? Hope this helps.