Two things which are more observations than help:
1.) Anything that happens only when it's raining means water is getting to an electrical connection. It shouldn't. Make sure all the connections are secure and water tight and not rusted. Make sure that all switches are not damaged and letting in water. Check the fan connection too. Download the Haynes manual in the download section of this site and have a read up on electrical issues.
2.) "i can't get the bike to sit at 100-120kph". Explain the issue a bit more please. In the dry, in the wet ? What happens ? What happens if you go to 140kph, what happens at 90kph ? How wide an issue is it and what are the symptoms ?
Cheers
Simon