I don't have a dg any I have a pro circuit head mod port and polish v force 4s air lid on
300 is prolly still too rich for that pro circut pipe, with the lid on, in the temps you had today.
try a 270/280 and plug chop them to confirm rich or lean.
if you plug chop/jet that bike today, it will fry in 20- degree temps, you either have to constantly rejet for these varying temps,
or better yet, do as i do...leave it sit till the temps get more consistant.
did you clean or replace and oil that airfilter ?