Te 450 Backfire On Startup

Hi All, need ur help pls

Recently picked up a 08 te450, first few times i started it cold i had no issue up until i gave it good wash and then ever since i have started its either backfired whilst turning over or made a popping noise only when starting cold and sometimes takes a couple of goes to startup. I am assuming its got something to do air/fuel? Anyone else had this problem or got any information on it? I have searched around but cant find anything!

Cheers!

Did you get water in the air filter?

Paw Paw

Perhaps, although i stripped the bike to get the frame painted and it was still doing it once it was back together. with and without air filter too

for first time today it didn't backfire from cold start, every other day the last week it has done it

Is the “backfire” through the exhaust, or is it actually blowing backward through the intake tract?