jbyun, it takes time for me to reproduce this problem. My daily office trip is less than 20 minutes, so I will have to test this issue on purpose or use weekend time. I plan to have dealer replace my tires recently, I will ask them this issue at same time once I can reproduce this problem. Do not want to waste their time and my money to replace this and that and end up problem still exist. I definite will update this thread once I got the answer.

 

Cool...thanks.

"Do not want to waste their time and my money to replace this and that and end up problem still exist."

You're too nice by the way because most stealerships will more than happily waste your time and money any chance they get

 

Any mods on it? Curious as to the out come.

 

No mod at all. All parts are from manufacture.

 

Mine is doing the same. Finally got an answer. After putting on th dybo found the high idle rpm is 2000-2300. Found AFR is off their chart, which tops out at 18. So the theory is that the ECM is calling for more fuel than throttle position, and thus overfueling for a bit. I have Vance and Hines Straightshots Slip Ons, SE air filter and Harley download to the ECM. No vacuum leaks, good gas, proper oil level, had stepper motor replaced and cables adjusted. So now I guessing next step is a tuner and more Dyno time.

 

I have the same problem on a 2008 Roadster Sportster 1200 fuel injection California model. Totally stock. I think a fuel enricher would amplify the condition.

 

The problem on my bike is a high idle condition of about 2,000 rpms. It occurs after about 10 miles to 20 miles of non-stop cruising at any combinations of speeds and gears.

The key to trigger the condition is the continuous moving. Once I slow, with the bike idleing at 2,000 rpms, it will remain at 2,000 rpms at 40 mph, 30 mph, 20 mph, 10 mph and less. If I accelerate away before stopping, the bike will continue stuck at 2,000 rpm indefinitely. Only a complete stop resets the condtion.

I have a camcorder I carry in my pocket, tied to my coat and I have video recordings of this situation that I've shown to to the service department.

Periodically, under this condition, the bike will over rev even more to 2,300 or 2,500 rpms until stopping. That is a seriously dangerous situation that I've mentioned over the phone to the Harley Davidsion customer service this week.

If I stop at short intervals as is the case for short trips or in town and most riding (or on a test/diagnostic drive from my local Harley Davidson shop) the condition will not occur.

Hence, I have not been able to get it fixed under warranty since the shop can't cruise down the freeway for 20 miles. My next step will be to bring the bike to a dealer that has a dyno that keeps the wheels moving. I just hope it's not related to the front wheel motion since there may be no such dyno that keeps both wheels moving.

 

It has been a while after my original post. I cannot confirm I have my idle issue fixed or not, but I did not see it again after I install battery pigtail myself in June.

While installing the pigtail, my unplugged max fuse, ECM module connector, and tie the pigtail ground wire together with the one original grounded on the primary inner case.

I am not tech guy, I cannot tell either it was caused by ground issue or some wires to ECM were loosen.

 

Ive had this same issue for a few yrs. Harley rreplaced my inj and sensors. It seemed to fix it , but it starting to do it again. I get fuel with everyone else and Im the only one with a problem, so its not a fuel issue. Its inconsistant so its hard to pin down what is actually causing this. anythime your RPMs wont come down to an idle-(about 2300rpm) that aint good. my problem actually advanced to the point of running very poorly then stalling at idle. Id start it back up and it would run and idle fine, take off and when I came to a stop , it would stall out again- thats when harley change the sensors and inj.

I have no idea what the hells wrong and niether does Haarley. Id guess its the ECU-but who knows

 

Okay. So I've never actually posted anything on here but after years of mooching I figured it was time to contribute.

Recently, I had the same problem with my 2008 Nightster. I would turn the bike on and she would idle normally.

I'd ride to work, about 35 miles, and she would start to idle REALLY HIGH. I could let go of the throttle and she would even accelerate on her own. I would sit at a light and it sounded like I was holding the clutch in and pulling back on the throttle.

At first I thought it could be a MAP or ECU issue. It wasn't.
Though it could be a voltage issue with the battery throwing the TPS (throttle position sensor) out of whack. It wasn't.
Checked for an intake leak &/or exhaust leak. Not an issue.


1. Intake manifold.
a. Bolts were starting to unthread themselves.
b. Manifold had A LOT of build up.
c. Gaskets looked OK but I used some gasket sealer JIK between the gasket and the flange.
d. When I tightened everything back up, I used lock tight to keep the bolts in place and di-electric grease over the gaskets to keep them in place and to suction onto the box.

2. Clean the jets using brake cleaner. (At first I thought it was crazy, but when I took a mechanics class at the local community college, the instructor swore by this stuff & no ****. It works! I've been doing it for years and never had an issue.)

3. Cleaned, lubed, and tightened the throttle cable/lines.

4. Cleaned the air filter & replaced the gaskets.

5. New fuel & Lucas Oil Fuel Treatment in lieu of Seafoam (it smokes to much).

Fired the bike up and haven't had an issue since.

I apologize for the really long post but the high throttle was driving me nuts and I could not find a fix online.
This worked for me. I hope it helps someone else out.

Abe

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