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Misfire under load? Thoughts?

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  #1  
Old 09-24-2016, 02:35 AM
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Question Misfire under load? Thoughts?

Hi All,

I was convinced that after a few baffle changes, my recent auto tuning sessions had reset the fuelling on my bike and it was running like a swiss watch. But on the way home from work tonight, I took the long way home and got on some open roads. This gave me the chance to put the bike through its paces. As I grabbed the throttle and held it wide open, it didn't like it. Pulled hard initially but then had multiple misfires when holding the throttle wide open? Back off and it runs okay?

I had something similar once before when my earth terminal wasn't tight. It wasn't loose either but was easily movable when pulling on the lead. .When I had this problem the tach needle would drop when it misfired. It isn't doing that this time.

Any ideas on what could be the cause?

TIA
 

Last edited by Mr_Taipan; 09-24-2016 at 02:39 AM.
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Old 09-24-2016, 06:34 AM
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Originally Posted by Mr_Taipan
Hi All,

I was convinced that after a few baffle changes, my recent auto tuning sessions had reset the fuelling on my bike and it was running like a swiss watch. But on the way home from work tonight, I took the long way home and got on some open roads. This gave me the chance to put the bike through its paces. As I grabbed the throttle and held it wide open, it didn't like it. Pulled hard initially but then had multiple misfires when holding the throttle wide open? Back off and it runs okay?

I had something similar once before when my earth terminal wasn't tight. It wasn't loose either but was easily movable when pulling on the lead. .When I had this problem the tach needle would drop when it misfired. It isn't doing that this time.

Any ideas on what could be the cause?

TIA
Did your auto-tune sessions include any similar wide open throttle exercises?
 
  #3  
Old 09-24-2016, 06:38 AM
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I'd say she's either starving or rich (fuel) on accel...what kind of tuning did you do on the bike?
 
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Old 09-24-2016, 08:14 AM
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Which gear were you in? You may have hit the Rev-Limiter. That does not sound or feel good.
 
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Old 09-24-2016, 10:15 AM
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Yes i did some autotuning throughout the rev range. Its definitely happening before it hits the limiter as I don't really rev it that high.
 
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Old 09-24-2016, 10:22 AM
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Make sure you have a good strong battery.Some EFI bikes will misfire when the battery is going bad.
 
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Old 09-24-2016, 08:30 PM
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I second Guzzi's suggestion.
Had hesitation under load that disappeared with a fresh battery.
 
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Old 09-26-2016, 04:54 AM
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Battery is fine and bangs the starter in well and it holds up fine when the bike isn't in use and i've not needed to put the tender on it.

I'm going to load up the original map and try that and see what happens. Should be able to use it tomorrow and will know more then...
 
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Old 09-26-2016, 08:43 AM
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Unfortunately auto tuning is no substitute for proper tuning, such as on a dyno.
 
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Old 09-26-2016, 08:58 AM
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Originally Posted by grbrown
Unfortunately auto tuning is no substitute for proper tuning, such as on a dyno.
True but then a dyno tune is static to the bikes set up, which is something I like to keep changing. So the PV is the best option for me.
 


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