Crashing in online servers

[jit]

So i've tried uninstalling and reinstalling the game 3 times, didn't work, i tried uninstalling and reinstalling the oem bikes and tyres 3 times, didn't work, i tried lowering and maxing out my graphics, didn't work. Even went as far as running the game in windows 8. I can go into testing and i can host my own server but when the server population is 10 or up my game usually just crashes. My whole 800 hours in the game i have not had this happen. I've tried pretty mush eveything i could think of. Please help i am stumped.