Brand new Street Bob just hits 1000mi.
No mods except the slip on exhaust.

I ride daily about 25-30mi.
When I start the engine, idle fluctuate around 1050-1150. Then as I warm up and ride the idle drops to 780-850 range. When I finish the ride home(when I’m about to get home, I ride very slowly to pass the neighborhood), the bike seems cool down and idle stays around 780-850 before turning off.

Today after the normal riding, when I get home idle was about 780-850 like usual, then right before turning off the engine, all of a sudden idle goes up to 980-1050 range. (Making Da-da-da-da sound...)

First I thought that I open the throttle a little bit by mistake (or throttle not returning) because once idle goes up, it sounds like rev tries to maintain high, just as opening up the gas.

But I didn’t do anything. So, I open up the throttle little bit in neutral, then puts in the idle - the idle fluctuates like normal situation for few seconds then go up again to higher range.

The thing is the idle sounds different.
Even in higher idle when I start the engine, I can feel the fluctuation and up-and-down rhythm. But in this case rev tries to go up just like opening up the gas little.

I check the throttle but it seems it doesn’t stuck.

Have you had any experience like this?
Why the idle rev suddenly goes up and try to stay in higher rpm (and feels/sounds like you opening up the gas little)?

Thank you.

 

Maybe the weather is warming up and you experienced the Engine Idle Temperature Management System (EITMS) for the first time. See your owners manual, EITMS in the index. Many people turn it off.

 

Thank you for the advice.

When I check the EITMS, it activates when ALL of certain conditions are met.

I’m in SoCal, and rode hotter day than today. And basically I ride the same course, almost same speed and same rpm. But somehow it happens today for the first time. I’m not even sure how ALL conditions mentioned are met.

I think I’ll turn this off and see again.

 

Good call on the EITMS; I leave mine on (as you should also, IMHO) and I get the same things a red lights in the warmer weather. It let's me know it's working. On the Road Glide I have a visual display on the Boom that says "EITMS Active." On the Softtails it's a "audible" indicator.

 

Yep. EITMS cutting in.

 

I've never turned mine on. I rarely ride in traffic, and I don't really notice the engine running that hot.

 

How would you turn that on ?
Got got it Google that one thank you

 

Or you could look in the owner's manual like I did.

 

I think a 750 rpm idle speed may be a bit low for ANY modern day fuel injected Harley to maintain safe oiling. If its not the EITMS your experiencing, then perhaps its written into the factory strategy, to bump the idle up a bit when engine temps get too high. Although it sounds counterintuitive a higher idle has the ability to better manage high engine temps through increased oil flow. If it happens again its easy enough to just turn your EITMS off to see if it is in fact EITMS. Just roll your throttle forward a bit past where it normally comes to rest when you take your hand off the right grip.

 

This. I find this happens once in a while during spring where it’s cold in the morning and then warms up.