OnTheEdge
04-12-2007, 01:16 PM
I've always been able to get my jetting right on. Plug golden brown, everything good. Now heres the story. My 400ex needed a rebuild, cylinder was actually oval. So I got a 415 JE piston, HC Stg 2, 42mm 450 carb, intake polished, hmf w/quiet core. So I started with 170 main, needle in 4th postion from bottom, 48 pilot & 2.5 turns out on a/f screw, 93 octane fuel. Seemed to run fine. Let it idle, put the plug, completely black. Turn the a/f screw back to about 1.75 turns out. Let idle, pull plug again, golden brown, nice. Now the rest of the throttle range plug comes out white and glazed. Headpipe not red & glowing like they some times are when lean. So I took the needle down to 2nd from bottom, plug looks the same. Bottom notch, runs like ****, plug black. Back to 2nd from bottom. Go up on main jet in steps, continuously white all the way through 200. Put in 205 main, runs like ****, plug black. 200 seems to have a little hesitation at about 2/3 throttle, seems rich, but plug is white. 195 it seems to run perfect. Anyone have any opinions? I dont see why the plug would be white still, cant be lean. No leaks anywhere.