Yz-125 fouling plugs!!

I’ve had my 2012 yz125 for about 6 months but I bought it in winter so I haven’t ridden it much and I’m just starting to ride it again but it’s fouling plugs every hour or so, I’ve checked the electrical system it’s fine, I’ve cleaned the carb and air filter.
The weird thing is it’s completely stock. Any ideas?

Yz-125 fouling plugs!!