Alright, I was going to wait till I ran out of gas to change ratios for summer, just for a little extra protection. But I'm impatient... lol so as most of us know 50:1 is 2.6oz per gal and 40:1 is 3.2oz per gal. I drained what was in the bike back into my gas can and I had about 3/4 gallon left. So 3.2-2.6 is .6 I then divided that by 4 for each quarter gallon, and got .15 then times that by 3 for 3/4 gallon. And got .47 or something close to it, so I added about .5 oz to get 40:1. Is my math right? If it isn't it's no big deal as tuning my bike doesn't really bother me. I do have a quick mix cup for the right mix when I get some fresh gas. Though I did snap my e clip in half that goes to the needle. (Sigh) So I have to go through my rc truck parts bag to see if I have one that fits.