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High cold idle. Help

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Old Jun 18, 2013 | 04:49 AM
  #1  
Kopi Ko's Avatar
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Default High cold idle. Help

Guys, please help with my situation, scratched my head on this one.

The bike is running OK, a bit rich, but OK. I have this problem after I opened last time for changing fuel filter.

The symptoms:
1. When it get started, the idle goes up to 3500 rpm. If I open throttle at this stage, the idle will go down, but back up if I close throttle.
2. After reaching around 60C (140F), it slowly creeps down to 2k. (I think this is when the wax idle works, so wax idle should be an OK) Stays there for awhile.
3. After reaches 80C (176F) (This should be the time when thermostat opens), the idle will come down and sit normally around 1.4k. The bike then runs smoothly.

A bit more info:
1. No FI lights at all.

2. Coolant level is a OK. I've checked and flushed and replace with new coolant.

3. FPR is OK. I have replaced with new one as soon as I bought this.

4. Fuel lines are OK. I've replaced fuel filter and return hose.

5. Vacuum hoses are OK. I've checked and replaced the ones that I can replace. Only those 2 that runs from the lower part of engine running to the airbox I haven't replace because I couldn't reach that. (I suspect this is the problem)

6. Idle screw is working, BUT, not that responsive as before I opened the bike. Before I can lower the idle down to 1k rpm, now the minimum idle I can reach when I fully closed the screw is 1.4k.

7. Recently replaced Air Filter to K&N and I also have remus slip-on. Could this be the reason of high idle? But after 176F the idle sits normal around 1.4k.

So, my best guess is there is a vacuum leak at the first stage of engine operation (before wax open). It could be those 2 hoses running to airbox, or PAIR hoses. But I don't know how to test this theory.

Anybody here have any thoughts about my situation? Really appreciate your helps. Thanks guys
 

Last edited by Kopi Ko; Jun 18, 2013 at 04:19 PM.
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Old Jun 18, 2013 | 06:37 AM
  #2  
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"A"
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From: Phila. PA-Bklyn, NY
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Air filter clean?
 
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Old Jun 18, 2013 | 03:05 PM
  #3  
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From: Stockton, CA
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how many miles on the bike? may need TB sync..
i had to do that since the lowest i could go for the idle screw was 1500.
fixed now.
 
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Old Jun 18, 2013 | 04:17 PM
  #4  
Kopi Ko's Avatar
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@"A" Air Filter almost new, just being replaced. K&N

@omg209 Good suggestion, I might need to redo the TB Sync again. Thanks
 
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Old Jul 2, 2013 | 06:59 PM
  #5  
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I think I just found the problem.

The clamps that hold the throttle bodies boots are very loose.
 
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