Tunning my 2006 yz450f after some mods. Anyway at idle and wot i'm spot on with jets. However right as soon as i give any amount of throttle till about 3/4 throttle i'm lean. Super lean right off idle and slowly gets better through the rpms. My needle is stamped NFPR, so i need a samller diameter needle, which i think should richen it up all the way through and put me where i want. What needle would i need to order from yamaha? Typically I'm familiar jetting aftermarket carbs and they have a break down of the different numbers and how they affect the size of the needle, taper, length etc.. But yamaha doesn't have a chart like this. Called a yamaha dealer and they simply said the last number is how rich or lean, but don't say where it is rich or lean... And there are needles with different leters in both the last digits. anyone have any idea on what i need or what the letters mean on the OEM needles?