Fast Idle Issue?
 

Recently my bike hass been acting up. Didn't want to start or idle at first. Cleaned the air filter, changed the plugs and coils (one had cracked a while ago but didn't hurt anything) and oil and it starts no problem now. After it warms up it runs fine. The problem comes when it should be at high idle. Should go to about 2000 RPMs for 2 minutes after startup. Well, during that time it's hunting around, going from 1-2k RPM. And then the normal idle doesn't want to stay where I set it. That may be normal though and based on current engine temp.

I'm thinking a shot of 104+ Injector Cleaner or Seafoam will clear up the issue. Haven't tried it yet. My other thought is to do some reading and see if there's a separate injector port or if the computer just holds the injector open longer. Not sure what that would prove, but any knowledge is good. I don't recall seeing the injectors on a periodic maintenance checklist, but she does have 33,000 miles on her. Also used a small amount of oil since the last change, but I can understand that with all the heat and short bursts of high RPMs from city riding.

Has anyone else seen this? Any experience in how to fix it?

wait so are you saying that the initial warm up when u start the bike cold, the idle jumps around between 1 and 2k rpms, and then its fine? how do you adjust the idle on the 650?.

Yep. There's a knob sticking off the side that controls a throttle stop for normal idle.

Oh, and I need to try to sync the TBs again when I find time. When I had it down to the coils I realized the gauge hoses need a clamp to fit the TB vacuum ports, so that didn't get finished.

I wud say its either the tb's out of sync or maybe a O2 acting up.

Is your efi a closed, open or multi loop system?

Could be the O2 sensor- hadn't thought of that. I did change my header, and with it the sensor. I'll try to find my old header and swap the sensor.

Not sure what type EFI... gotta research.

The O2 sensor isn't working yet..

Could be semi clogged injectors.
Resink TBs.
Carbon on throttle plates.
Coolant Temperature Sensor.
Base Idle Speed set incorrectly high or low.

Kind of a "Bubba" Trick for locating vacuum leaks is take a can of carb cleaner and spray slowly along the vacuum lines if idle speed increases the leak is in the last place you sprayed. I have had good luck with Seafoam

Do you have an O2 sensor hooked up with your new exhaust? I saw on a forum that the guy had to add a bung to his mid pipe for his Two Bros setup.

Also check to see if the yellow paint on the throttle part of the right TB. If any of them have moved then that could be it.

Well, it's definitely not the O2 sensor. Doesn't have one. I think it's only on Euro or CA spec bikes. The throttle plates look great. I took a good look at them when I had the air box off. I think the temp sensor is working. The light was on a while ago when I was stuck in the city and it was 90 out. The Idle speed is right. After riding to work or anything, I'll check it before I shut it off. 1300-ish RPMs. The manual calls for 1350 give or take 50.

So the only thing I'm left with is dirty injectors or TBs out of synch. Have to get that injector cleaner and some small hose clamps.