Author Topic: bang and idle dropped  (Read 2159 times)

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Offline Clue

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bang and idle dropped
« on: May 19, 2008, 07:53:00 am »
Coasting downhill to a stop yesterday I heard what sounded like I'd run over an flattened can (a brief sort of metallic clatter) and suddenly the bike's RPM dropped to the point I thought it would stall out.  A quick adjustment to the idle knob at the stop-sign brought it up above stalling but it doesn't sound like all cylinders are firing.     11 yards of mulch awaited me at home so Connie-Lingus stayed parked yesterday.    
COG #6816  '96 "ConniLingus"

Offline duffy

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bang and idle dropped
« Reply #1 on: May 19, 2008, 09:26:00 am »
Missing sparkplug???  Pull the tank, and look at the sparkplugs.  Were there any other noises??  Just a single "BANG"??  
2002 C10 "Charlotte"

Offline Greg Habel

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bang and idle dropped
« Reply #2 on: May 19, 2008, 10:39:00 am »
Make sure one of the plug wires didn't come off.  Pull the plugs and look at each one to see how they are burning.  Greg  COG # 7010/7010a (Tracey)  CDA 0120  Connie Droppers Anonymous Awards Dude (CDAAD)  99 Connie "Herrin Christabelle".  05 Ninja 250  
Greg H from Mass -  MA/ME/NH/VT co-AAD 2012+ with wife Tracey
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Offline smithr1

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bang and idle dropped
« Reply #3 on: May 19, 2008, 12:34:00 pm »
Did you happen to just wash the bike or leave it in the rain?  Then yes check the plug wires are connecting to the plugs.  Not liking the sound of "metallic clatter"  Do you really want to know all the bad things it could be?    <p align="left">My Photos
 
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Offline Clue

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bang and idle dropped
« Reply #4 on: May 21, 2008, 04:28:00 pm »
Ummm....not just yet.  Keep me hopeful for now.    I tested the "something awful just happened" theory by accelerating away from the stop sign up into 6000+rpm range, figuring "if it wernt broke before it sure will be now" and nothing ill occured.    I hope to pull the tank tonight.  My worry is that I've got one carb leaking fuel into a cylinder, had some hydro-lock and blew a plug out of its threads.  Something which a heli-coil might heal.  I discount this theory a bit though since I traveled 3/4 a mile from driveway to "bang/clatter" and I'd expect hydro-lock to announce itself at start-up or clear itself within 1-2 crank rotations.    I'll post back with what I find under that tank tonight.      
COG #6816  '96 "ConniLingus"

Offline Clue

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bang and idle dropped
« Reply #5 on: June 02, 2008, 12:30:00 pm »
      [list=a]  
  • Checked the plug wires.  No problems.  
  • Pulled the carb bank and fiddled with diaphrams, slides and cleaned up the linkage a bit (dusty, not grimy)  
  • Reinstalled the carbs and fiddled with the throttle and choke cables.  
  • Pulled off the clutch cover mostly because I was curious but also so I won't drive myself crazy wondering whether every little noise from the right side of the motor is a warning or not.  
  • Put it all back together, cursed a blue streak and now it runs fine.  
I'm sure it was the cursing which "cured" it.    
COG #6816  '96 "ConniLingus"

Offline smithr1

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bang and idle dropped
« Reply #6 on: June 02, 2008, 02:56:00 pm »
Good to know its all better.  Bad anytime you don't know why.   ----------------------------------  I will answer any question.  It is up to you to figure out if I should have.    <p align="left">My Photos<br
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Bob Smith (smithr)
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Offline Clue

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bang and idle dropped
« Reply #7 on: June 13, 2008, 03:21:00 pm »
Wishful thinking on my part again!    Same problem again.  Bike needs FULL choke to start and needs choke for 5-10 minutes or it will stall out at idle.  Sounds like 3 cylinder not 4 at idle but at full whack it opens up and feels smoother.  Acceleration is sluggish in mid-range, stumbling at idle and low-range.    A carb rebuild has finally fixed it.  (with a valve adjustment thrown in to boot 'cuz that's actually less difficult than wrestling with the carb bank re-install.)    Can someone who knows carbs explain what the likely culprit was which a tear-down, clean-out would have addressed?  (I can disassemble/reassemble and understand the rudimentary theories but that's about it.)  I have heard that carbs typically have two circuits for fuel metering (idle circuit and wow circuit?) so I am guessing my clog/obstruction was within the idle circuit but I'm smoking brain cells to muster this theory.    I'm curious to hear the speculations of someone actually competent.    
COG #6816  '96 "ConniLingus"

Offline norm-9688

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bang and idle dropped
« Reply #8 on: June 13, 2008, 03:36:00 pm »
It sounds to me like the carbs were running just rich enough to foul the plugs in one or maybe two cylinders. My bike did it about to weeks ago. I almost turned around to go back home but it cleared up after a few miles. Was skipping bad in low RPM but ran fine above 5000 or more. All it takes is for the float level to be just a little too high and it will run rich enough to do it. If it does it again I would pull the carbs and replace the float needles and set the levels. I'm going to have some carb kits on hand for my bike it it does it again :)  CT AAD  COG #7011-A  2003 Concours-Mary Ann  1995 Honda Nighthawk 750 wifes