SR 50 Question

Been around on this forum for a while having a read, was previously on but forgot my details.

I've got a little problem with my scooter.
Its an SR 50 LC Stealth 97-01 minarelli engine.
I've been having trouble with it when it rains, it starts to splutter out then wont start until the following day, then it works fine if its dry. If it's wet it won't work again.
I was out on it the other day and it started to rain, pushed it home and left it over night, when i went to ride it the next day it would rev fully on the stand but once taken off the stand it wouldn't move and would sometimes cut out.
I've been told the problem could be the rollers, is this true?
Also what would be the most likely problem to the rain? would it be the carb as the spark plug has recently been changed and a new HT lead put on, so doubt it can be that.

hiya I used to have the same problem on one of my old bikes when I was out in rain it would just get right boggy and just wanna cut out I had a open filter on mine so imagined it was that sucking water in do you have a open filter on yours mate

I've got the standard big box one, ive just ordered a new K&N style one with a waterproof cover to see if thats the problem though.

Best to leave the std airbox on it so it run's right, maybe get some wd40, silicone lube and spray all over the spark plug/ electrics/cdi etc.