Just joined thumpertalk to get some advice on my new bike i just picked up. I just got an 04 RMZ 250 and it seems like it has some issues, doesnt seem major but i would like to get it running better. only modification it has is the back half exhaust and i just replaced the air filter. anyways the bike seems to run great i have put about 10 hours on it since i got it but i noticed oil is leaking out of this thick black tube by the swing arm. the bike was filthy when i got it, covered in oil, so i dont think the guy maintained it that well. i have cleaned the carb and replaced the air filter. after doing that bike starts way easier and idles better. especially when hot. Do the jets need to be changed cause exhaust? Valve need adjusting probably lol..why is it leaking oil?