Copying this from the tech thread as there was no response.

I am new to this whole throttle by wire so this could just be a misunderstanding on my part.
My new to me 08 Ultra, when I am slowing and let off the throttle it idles down slowly then a second or so later it sort of cuts out and idles down quickly.

A bit of a different way to describe it is that when I completely let off the throttle it seems to coast at relatively the same engine speed for a second then starts to reduce. I am not sure if this is just an electronic delay related to the throttle by wire or if perhaps I have an issue.

Background: 08 Ultra
103 kit
SE 255 cams
SE street cannon slip ons
SE stage 1 intake with K&N
V&H FuelPak

I have recently retuned the FP because I learned that the map was set incorrectly. The behavior described is absolutely the same before and after retune which made me wonder if this is just the way the electronic throttle behaves.

 

Not sure if you have stock bars or grips. But this is a common problem why it would act as you describe. If the chrome build up on the bar is to much to allow the grip to return to neutral as it should.

Another thing that can make your throttle act all goofy is your tune is wrong. There are threads that explain how to change the positions or response of the throttle in the tune

 

Wonder if doing the throttle recalibration in the service manual may reset it also.

It is only at low speed that i notice it.1st or 2nd gear.

 

it may be an emissions thing - so the rpms don't drop so much when you shift

 

Try calibrating it is where I would start. Unless like in said you have new grips on it

 

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The reason the retune had no affect is because what you describe is how a properly working EFI system works when you let off the throttle while still cruising in gear then a second or 2 later the motors exhaust note/sound changes seemingly quitting and the motors compression then acts like a brake until you either hit the throttle again or come to a stop pulling in the clutch to find the motor returning to a normal idle speed which is normal EFI operation having nothing to do with the TBW.

As long as the motor seems to be running well (other then what you described above that BTW is the same thing my 09 96" w-EFI does) its simply normal EFI operation & no need to fix whats not broken!!/LOL!!!

Scott

 

I was wondering that myself. It does have aftermarket grips but they came with the bike. I purchased in January.

I was thinking that it may just be the EFI and electronic throttle.

In the case of changed grips: What is the procedure for changing them? Is it in the service manual on how to make sure it is recalibrated properly after a change? I have a manual.