Counting the teeth on item# 9 and # 12(small gear) Divide #12 into #9. If I understand your post correctly 42 ~ 17 = 2:47. What you want is a 40 tooth and 13 tooth for a ratio of 3:08. I do have these gears in stock . Give me a call @ 662-301-1563 or e-mail me your number with a good time to call.
tom@sycpowersports.com
Tom