7-7SETTING TUNEC719081Jet needle adjustment(For EUROPE)On the carburetors used in the YZ250, the mainnozzle is press-fitted, so it can not be replaced.Therefore, carburetor setting requires the changeof the jet needle.1. The jet needle setting parts, having the sametaper angle, are available in different straightportion diameters and in different taper start-ing positions.N3EW - 3Clip positionDiameter a of straight portionTaper starting position bA Difference in straight portion dia.B Difference in taper starting positionc Richd Lean2. Effects of changing the jet needle (reference)9 Diameter of straight portionChanging the diameter of the straight por-tion adjusts the air-fuel mixture when thethrottle is 1/8 to 1/4 open.9 Taper starting positionRich N3EW-4th grooveN3CW-4th grooveN3EW-3rd grooveN3CW-3rd grooveLean N3EW-2nd grooveChanging the taper starting position pro-duces the same effect as changing the clipposition by 0.5 groove.In case of being 0.5 groove leaner in rela-tion to N3EW-3rd groove, choose N3CW-3rd groove.A In case of being 0.5 groove leaner in relationto N3EW-3rd groove.a Difference of 0.5 grooveStandard jet needle N3EWN3CWN3EWåa11 22 334 54 50.50.50.50.5
