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2007 gt125r compression test

This topic has 4 replies, 2 voices, and was last updated 7 months ago by ♠️ MARCEL.

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- Oct 9, 2024 at 3:34 PM #15127
  Brian
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  Topics: 18
  Replies: 33
  Done a compression test on my 2007 gt125r, had the bike up to temperature before test,full throttle and charges battery, readings are 135 on each cylinder, the spark plugs are also fouling/black and sooty. Are these readings OK or should this merit further investigation? I would hope it was just an over fueling issue so I wouldn’t have to strip the engine down. Thanks
- Oct 9, 2024 at 5:24 PM #15131
  ♠️ MARCEL
  Admin
  Topics: 44
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  🌍 Country: UK
  ⚡ Bike Model: GT
  Warm up the bike again,
  
  Then remove both spark plugs , crank at full throttle for 5 seconds
  
  And tell us the readings again in PSi if possible.
  
  Regards
  
  // Meditation doesn't mean you have to sit still....
- Oct 10, 2024 at 11:58 AM #15140
  Brian
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  Topics: 18
  Replies: 33
  So I got the engine hot and tested again. Psi was 125 each cylinder, I seem to loose 10 psi per cylinder when hot.
- Oct 10, 2024 at 2:27 PM #15141
  Brian
  Member
  Topics: 18
  Replies: 33
  I really should mention the bike was on its side when it was delivered,so oil could have made its way up into the cylinder, the rear cylinder is 100 percent burning oil. I just don’t understand why the compression readings are the same in both cylinders.
- Oct 10, 2024 at 6:49 PM #15144
  ♠️ MARCEL
  Admin
  Topics: 44
  Replies: 2,428
  🌍 Country: UK
  ⚡ Bike Model: GT
  Burning Oil = Piston Rings . Scored Barrels , or Valve SEATS dripping oil in to piston chambers (hence probably sooty plugs) or simply rings on the way out with the barrel.
  
  125 psi = You’re literally at the limit as to what hyosung considers a time to rebuild engine. Generally 150-175 psi is expected.
  
  // Meditation doesn't mean you have to sit still....
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