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19th October 2011
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Biker
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Join Date: Aug 2008
Posts: 49 Sportster/Buell Model: XL1200C 105th Anniversary Sportster/Buell Year: 2008
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Does Your EFI 1200 Do The Herky Jerk With Throttle Just Barely Cracked?
Does your bike do this too? 
Conditions: Any gear, but for example, 2nd gear, about 2,000 rpm and holding (throttle just barely open)
Symptom: frequent but not cyclical "stumbles" - i.e. feels like fuel or ignition just cut off for a tenth of a second then came back on.
Get above about 2,200 rpm and it stops.
I've had this issue since new. 3 different dealers have said it's "normal" for EFI Sporties. I'm starting to believe it's true.
I've tried to tune it out using the SEPST with no luck. Ultimately gave in to dealers' suggestions to dyno-tune. Still does it. The guy who actually runs the dyno says can't get rid of it - it's the nature of the beast for EFI Sportsters, which seem to use less sophisticated programming than Big Twin EFI. |
19th October 2011
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Know It All
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Join Date: Mar 2011
Posts: 150 Sportster/Buell Model: 1200c Sportster/Buell Year: 2007
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My 07 1200C stumbles as well. Been tweaking my cobra module trying to get rid of it for months, but nothing has helped. Good luck..
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19th October 2011
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Biker
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Join Date: Oct 2010
Location: san joaquin county,ca
Posts: 52 Sportster/Buell Model: XL1200N r.i.p. Sportster/Buell Year: 2008 Sportster/Buell Model #2: XL1200R sold Sportster/Buell Year #2: 2005 Other Motorcycle Model: HD FLD aka switchback Other Motorcycle Year: 2012
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look into the dynojet powervision it fixed the problem you are talking about plus no need to go to dyno shop you have it right on your bike. you can tweak everything plus you can read and clear check engine or stored codes. well worth the money
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knucklehead of the Cracked Craniums MC
Last edited by SpaceAce; 19th October 2011 at 19:27..
Reason: kant spel
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19th October 2011
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Senior Chief Master Mechanic 2nd Class
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Join Date: Sep 2010
Posts: 1,537 Sportster/Buell Model: XL1200R SOLD Sportster/Buell Year: 06
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Just an FYI, 2000rpm is lugging the engine and will cause "herky jerky". Get those rpm's up. A carbed (like mine) will do the same thing at a steady 2000rpm. It's not good for these motors. You're actually hurting the engine at constant 2000rpm.
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Old Goat Ninja = user formaly known as Starleak
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19th October 2011
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Turbo Mafia
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Join Date: Jul 2010
Location: North East PA and NJ
Posts: 1,616 Sportster/Buell Model: Turbo Nightster Sportster/Buell Year: 2010
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Quote:
Originally Posted by SpaceAce
look into the dynojet powervision it fixed the problem you are talking about plus no need to go to dyno shop you have it right on your bike. you can tweak everything plus you can read and clear check engine or stored codes. well worth the money
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Was just going to post the same thing..my bike no longer does it.....even down to about 1500 RPM its still steady
The dealer calling it normal just mean its normal for the EPA tune that the bikes come with..I'm surprised your dyno guy could not tune it out...
Quote:
Originally Posted by Starleak
Just an FYI, 2000rpm is lugging the engine and will cause "herky jerky". Get those rpm's up. A carbed (like mine) will do the same thing at a steady 2000rpm. It's not good for these motors. You're actually hurting the engine at constant 2000rpm.
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Yes, but if your in traffic in 1st gear and just barely moving, you have no choice but to run at that RPM.....sure you could fan the clutch, but with a proper running bike, you don't need to do that.
and at 2000 RPM your not lugging the engine unless your trying to quickly accelerate in the wrong gear ....my bike pulls just fine from 2000 RPM in 1st 2nd or 3rd gear ..4th or 5th and it will lug
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19th October 2011
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Senior Chief Master Mechanic 1st Class
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Join Date: Feb 2009
Posts: 1,219 Sportster/Buell Model: XL1200C Sportster/Buell Year: 2010 Sportster/Buell Model #2: XL883 SOLD Sportster/Buell Year #2: 2007 Other Motorcycle Model: Kawasaki Ninja 250R Other Motorcycle Year: 2008
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Mine does it too, lean fueling to pass emission tests, EPA and CE requirements.
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19th October 2011
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XL FORUM LIFE MEMBER
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Join Date: Feb 2007
Location: Pittsburgh, PA
Posts: 13,149 Sportster/Buell Model: XL50 0596 Black Sportster/Buell Year: 2007 Other Motorcycle Model: E-Glide Other Motorcycle Year: 2003
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FWIW mine fine.
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Bob, a glutton and a winebibber, a friend of bartenders and sinners!
Sportys tend to keep getting faster the longer you own them.
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19th October 2011
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Senior Chief Know It All 2nd Class
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Join Date: Oct 2007
Location: Southwestern Minnesota
Posts: 1,450 Sportster/Buell Model: XL1200 Low/TTS/Gronked Sportster/Buell Year: 2007 Sportster/Buell Model #2: XLCH1000 Sportster/Buell Year #2: 1975
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Quote:
Originally Posted by SNMbass
Does your bike do this too?
Conditions: Any gear, but for example, 2nd gear, about 2,000 rpm and holding (throttle just barely open)
Symptom: frequent but not cyclical "stumbles" - i.e. feels like fuel or ignition just cut off for a tenth of a second then came back on.
Get above about 2,200 rpm and it stops.
I've had this issue since new. 3 different dealers have said it's "normal" for EFI Sporties. I'm starting to believe it's true.
I've tried to tune it out using the SEPST with no luck. Ultimately gave in to dealers' suggestions to dyno-tune. Still does it. The guy who actually runs the dyno says can't get rid of it - it's the nature of the beast for EFI Sportsters, which seem to use less sophisticated programming than Big Twin EFI. |
Symptom: frequent but not cyclical "stumbles" - i.e. feels like fuel or ignition just cut off for a tenth of a second then came back on.
See the "Stumble on Cold Start-up" sticky fourth from the bottom on the main page.
I've tried to tune it out using the SEPST with no luck. Ultimately gave in to dealers' suggestions to dyno-tune. Still does it. The guy who actually runs the dyno says can't get rid of it - it's the nature of the beast for EFI Sportsters, which seem to use less sophisticated programming than Big Twin EFI.[/QUOTE]
Big twins don't use a more sophisticated program, in fact it's basically the same with just a few more features. The stumble can be tuned out, mine was with a SERT.
__________________
If your feet smell and your nose runs, you're upside down.
U.S.A.F. Veteran
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19th October 2011
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XL FORUM TEAM MEMBER
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Join Date: Jul 2007
Location: Southern New Jersey
Posts: 1,792 Sportster/Buell Model: XL1200C Sportster/Buell Year: 2007
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No stumbles here...
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19th October 2011
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Senior Master Custom Bike Builder
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Join Date: Dec 2006
Posts: 4,794 Sportster/Buell Model: 1200 Low Sportster/Buell Year: 2007 Other Motorcycle Model: Yamaha FZ1 Other Motorcycle Year: 2008
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It just needs tuning. The problem is you bought a tuner that needs a $25000 dyno and a guy that understands what he is looking at.
Beast
__________________
.
Regarding engine mods, it all depends what you are driven by......
Bling, bragging rights, silky smooth power delivery, a little more peak power, violent power delivery,
traction or wheelie limited acceleration, a sound that just drips testosterone or peace of mind that
everything is as perfect as you know how to make it.
When the racers get done doing the impossible the engineers get a chance to correct the errors in the model.
***My other addiction, running Megasquirt EFI ***
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