About 3 years ago I had some warranty work done on my ‘16 street bob where the idle was creeping up higher and higher to where it eventually threw codes once it hit like1600 at idle.

At at the time, I just remember them mentioning a screw for the idle or something got loose and once they tightened it back up, all was well.

Well, it’s slowly happening again but I’m not quite sure what exactly I need to tighten to fix it. Wish I had paid more attention back then so I could fix in the future.

 

You probably need to adjust the throttle cables.

It's in the service manual. Here's a Link

 

There is no screw or mechanical way to adjust the idle speed. The screw on the throttle body is to adjust the opening of the butterfly flap. If you have a tuner you can usually change the idle, and if you don't the dealer can do it electronically.
Before you do anything else, except for checking the throttle cables as recommended above, it would be a good ideal to clean the IAC.

 

Hello,
I had the same or similar issue. I was getting a high idle code. Dealer couldnt figure out. Ended up costing me $300 for what they said was a manifold leak. They said when the bike is idling, with your finger, cover the IAC. The bike should stutter and die. It wasn't. They obviously don't check there work. When i got home, same problem. Covered the IAC and it still runs fine. Turns out the screw that stops the butterfly in the back of the throttle body had no loktite from the factory. I adjusted it until the bike would sputter and put loktite on the bolt. That was 3 years ago and I haven't had the issue since. As your riding and there is no pressure on there screw, the vibration causes it to back out, holding the butterfly open more then normal. There is a factory bulletin about this issue. If I can find it i will post it. This might be a good place to start. Good luck.

 

This sounds more like an intake leak getting progressively worse. Check if your intake flanges are loose.

 

Great document, thanks

 

doubled

 

Sounds like it is more plausible. I've always heard you shouldn't mess with the throttle home position screw. I don't see how it would get loose as they put red loctite on that. If it did, someone was messing with it and it would have fallen out before you noticed much change in the actual idle. Adding, you may want to check the throttle position sensor as well.

 

Yes that screw is very hard to just loosen. It’s also a special Allen key

most of these high rev at idle cases are intake seals or adjustment. The backing plate has to be loosely fitted when fitting throttle body and i think a lot of people don’t do this either as not much space in there

 

I was able to turn the stop screw by hand. No loctite from the factory. Other people have reported the same issue on the forum.