jdubois
Jedi Warrior
Offline
I finally got around to ordering new needles for the carbs in my '65 Spit, because I knew one was slightly bent and figured it was about time. Well, when I pulled the old needles out I noticed they're marked 007. The new ones I ordered, as is specified in the owner's manual, are marked 'AN'. So, I looked up the needle charts in the old "Tuning SU Carbs" book and plotted them to see what the difference was between the 7 and the AN. Well, I was pretty surprised at what I found. The 7 seems to be an EXTREMELY rich needle. What the heck? Why would somebody put such a rich needle in? Wonder if that's why my fuel mileage was never quite what I thought it should be.
See my chart below (it plots the jet opening, not the needle diameter, so higher value is richer). The orange line is the stock AN needle, the yellow one is the "rich" needle (H6) specified in the owner's manual, and the blue one is this 7 needle.
See my chart below (it plots the jet opening, not the needle diameter, so higher value is richer). The orange line is the stock AN needle, the yellow one is the "rich" needle (H6) specified in the owner's manual, and the blue one is this 7 needle.