The yz400f had a hard time starting up the last couple of times out. In the summer months it's started first kick hot or cold thats was anywhere upto 110 degrees. Now that it's in the negatives and single digits it won't go without 1 or 2 twists of the throttle and stalls a couple times before staying lit. I will probably be riding all winter in negative double digits. Should I move the needle up a clip?? I'm sure I have big enough jets in already 48 65 and 180 main I believe my fuel screw is out 2 turns maybe 2.5. Maybe my oil is abit to thick? I have fresh rotella 15/40 in now, just started running it afew hours ago seems great so far switching from amsoil 20/50 it was to rich for my blood.