4 Litres is about 3 1/2 quarts, when you check it you do let it run and then shut it off, put it on the center stand and wait about 5 minuts then check. If there is a air bubble still able to be seen in the glass you are ok. There is no real damage you can do unless you way overfill by a couple of quarts, they you can run the risk of hydrolocking, it would also be smoking alot. Hope this helps
Chad Falstad "Hawk"
2011 HD Ultra Classic "angel"
2001 Nomad 1500 Sold March 2012
2001 VN 750 "Sold June with 2008 with 21,000""Serinity"