chimpy Posted October 9, 2008 Share Posted October 9, 2008 Hello, I've fitted a CRD Absolute Power II exhaust followed by lowering the needle clip one notch and raising the main jet by ten points as per instructions from CRD however i just carried out a "plug chop" at 4,000 and found the electrode to be mostly covered in white so it appears to be running lean. Is there anything else i can do? Thanks Joe Link to comment Share on other sites More sharing options...
Moderator Airhead Posted October 9, 2008 Moderator Share Posted October 9, 2008 Was the plug chop done at full throttle or part throttle? you should plug chop at full throttle first to get the main jet right, Once youre happy there re adjust the pilot air screw to suit. Then plug chop at 1/2 throttle to get your needle position check. Also did you change main jet type for type, ie brass hexagon for brass hexagon for example? Link to comment Share on other sites More sharing options...
chimpy Posted October 9, 2008 Author Share Posted October 9, 2008 Was the plug chop done at full throttle or part throttle? you should plug chop at full throttle first to get the main jet right, Once youre happy there re adjust the pilot air screw to suit. Then plug chop at 1/2 throttle to get your needle position check. Also did you change main jet type for type, ie brass hexagon for brass hexagon for example? Chop was done at only part throttle at 4000rpm! The jet was like for like, a genuine yamaha part, i went from 130 to 140. Thanks for the reply Link to comment Share on other sites More sharing options...
Moderator Airhead Posted October 9, 2008 Moderator Share Posted October 9, 2008 Chop was done at only part throttle at 4000rpm! The jet was like for like, a genuine yamaha part, i went from 130 to 140. Thanks for the reply You need to do both chop as i said, its only when main jet size is right that you would do any chop part throttle. But if youre happy with the main jet, (Personally i cant see it being far out), then it looks like you should raise the needle again despite what they told you. I think you have done right to do this testing and not just take it as said!. Better rich than lean as you know lean = overheating = engine damage Link to comment Share on other sites More sharing options...
chimpy Posted October 9, 2008 Author Share Posted October 9, 2008 I will try lifting the needle again at the weekend and see what that does. Thank you for being so helpful. Joe Link to comment Share on other sites More sharing options...
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