Hi Guys,
I have a Suzuki gsf600. A while back I seemed to be having power related issues, particularly in the cold and before the bike was warmed up. I had replaced the spark plugs and everything was super.
I rode to work today in torrential rain and, thankfully as I got to work the bike started losing power. It doesn’t stop entirely but it shudders and is very slow to pull away.

Any suggestions as to what the problem could be?