CR125 Too Lean?

This topic has 7 replies, 6 voices, and was last updated 10 years, 11 months ago by Todd Kageals.

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- August 30, 2015 at 4:04 pm #53594
  
  jim lewis
  Participant
  
  Todd,
  
  The pop and lack of power indicate a lean condition. Light tan on piston also indicating a lean condition.
- August 31, 2015 at 8:57 am #53627
  
  Chris Hegar
  Participant
  
  1999 kit motor or 2001?
  
  What pilot and needle?
  
  I’m guessing this was at Buttonwillow?
- September 1, 2015 at 7:57 pm #53733
  
  James O’Brien
  Participant
  
  Your piston should be smooth and covered in carbon.
- September 2, 2015 at 5:23 am #53740
  
  Rodney Ebersole
  Participant
  
  James O’Brien, Going from 20 parts gas and 1 part oil, to 32 parts gas and 1 part oil is not adding more oil to the mixture.
  - September 2, 2015 at 1:47 pm #53786
    
    James O’Brien
    Participant
    
    Ratios and drinks do not mix, thanks for the correction Rodney
- September 2, 2015 at 11:39 am #53776
  
  Jimmy McNeil
  Participant
  
  20 to 1 is a rich mixture (even for road racing) and may even be contributing to the speckling your seeing on top of the piston. Think that comes out to 6oz per gallon, go to 4.5 or 5 oz. Running a rich fuel/oil mixture = leaner in the combustion chamber. The popping your hearing is common with a lean condition.
- September 27, 2015 at 11:24 am #54814
  
  Todd Kageals
  Participant
  
  [quote quote=53627]1999 kit motor or 2001? What pilot and needle? I’m guessing this was at Buttonwillow? [/quote]
  
  Chris,
  
  This was actually at Summit Point, WV. I don’t know what pilot I was running as I have never swapped the pilot. I was under the impression that the pilot only affected the mixture at part throttle (I’m almost never part throttle at SPR). The popping only occurred at full throttle on the main straight. Needle was DGJ. I think 20:1 is the spec ratio for our club. The motor is a ’99 but I built it from an old dirt bike motor (completely rebuilt including the 6 speed). I did notice that I am missing the rubber boot that goes on top of the carburetor around the cable. Not sure how much that would affect it.
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