nickxc Posted July 15, 2004 Report Share Posted July 15, 2004 Im trying to dial in my jetting close, I wanna leave it just a little rich cause sometimes I leave the house and its 80 degrees then im comming home late at night and its like 50degrees. I wanna be safe at 50 and still run good at 80 if possible, anyway... 2. Reading the base ring to determine jetting: The base ring "color" is very close to the color of the piston crown and is used to determine the jetting. You're looking for the soot color to be a nice light to medium brown, (color is always hard to describe) if the color doesn't go all the way around the base ring (at least one full thread turn on the plug) or the color is whitish it is way too lean. If the color goes all the way around, but there is a spotting of heavy dry soot on the top of the color, you are too rich. how acurate is this??? my base ring is black with spots of soot and a little wet on the threads (could this be from running 390 mains and mixing 20:1 durring my break in???? ) should I clean them off then ride and see if they get black again??? Im currantly running 370 mains toomey needles at 4th down from top, 30 pilots with air screw 2 turns out. foam filter with the mods in my sig. also. I believe I read that you should jet up till you have a stumble on top end then down one size. I cant seem to get a "stumble" I went up to 390 mains and I dont think I should have to go much higher than that I just have a mild "clean up" port job with vitos ss pistons, v force, and sst's... when you say stumble... when I reach the very top of some of the gears it seems to gurgle a little but I dont seem to get it in the top of 6th???? is this the stumble I hear of??? sorry this is so long... anyone with helpful info would be greatly appreciated. (Im a chicken shit and am afraid to keep going down on my mains) Quote Link to comment Share on other sites More sharing options...
sredish Posted July 15, 2004 Report Share Posted July 15, 2004 How is the coloring with the 370s? The coloring for the 390s sounds like you've got plenty of color and are running good. Was this in 50 or 80 degree weather? Personally, I would try to jet it at 50 with the lid on and then see how it runs at 80, if it wants to sputter or foul, then pull the lid and see if that clears it up, if so, run another plug check like that to be sure it didn't lean out and then your good to go. Scott Quote Link to comment Share on other sites More sharing options...
Ducman Posted July 16, 2004 Report Share Posted July 16, 2004 First Read and try doing BenBB's plug chop method. Warm up the bike to full operating temp, throw in a NEW set of plugs. Go WOT through the top of 6th holding it at WOT in 6th for about 5+ seconds. Kill the motor and pull in the cluth, pull the plugs, cut a section of the threaded part of the plug off to make a window so you can examine the base of the electrode insulator. If the brown ring at the base of the insulator is larger than 2mm and very dark in color then it is too rich. Most of the insulator should still look white and nearly new, your just looking for the 2mm ring at the base. Or an alternative metod is to use your old plugs, the darker the insulator the better, and do a WOT test like mentioned before, only do several passes running it up through the gears, then kill the motor, then check the general color of the electrode insulator. Light brown good, medium brown a little rich but also ok, dark brown to black too rich, very light brown or approaching white near the insulator tip is to lean. Quote Link to comment Share on other sites More sharing options...
nickxc Posted July 16, 2004 Author Report Share Posted July 16, 2004 I guess when we get some good weather I will have to cut some plugs and get an idea of my main jets. once they are dialed in I should be able to dile everything else around them right.... Quote Link to comment Share on other sites More sharing options...
sredish Posted July 17, 2004 Report Share Posted July 17, 2004 ...my main jets. once they are dialed in I should be able to dile everything else around them right.... that's the way I do it. Main first, then work down. Quote Link to comment Share on other sites More sharing options...
nickxc Posted July 17, 2004 Author Report Share Posted July 17, 2004 cool thanks for the help!! Quote Link to comment Share on other sites More sharing options...
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