Hi guys, want to say hello as im new to this forum and looking for suggestions with my problem with cbr 125 06. When it starts to rain more heavily it suddenly stalls, usually on low revs when im opening the throttle but happened on a motorway too. When i try to start it later I can increase the revs if i do it very slowly on neutral but when I do it faster the engine backfires and revs keep falling. After a few attempts it will not start at all though and I have to wait for a bit to get it working again.
Any ideas? Thanks in advance

 

This looks to me weak spark..so I'd look at spark plugs. But not sure what rain has to do with it. Unless your coil is loose and rainwater somehow seeps in from the head when it rains heavily Do you see any electrical gremlin when it rains like light dimming etc ?

 

I didnt notice any of that, it turns over well for many times when i am trying to start it.
Im thinking about air filter because its a bit worn is it possible that it might let too much humididty to the engine so that its harder to ignite?

 

you're getting water in to the coils. Pull the boots off the coils and dry it out really well. check the boots for damage/cracks. Use a dielectric grease inside the coil where the boots plug on and try that for moisture barrier/protection