Ridiculously high idle after riding

So the bike starts just fine, idles well. No issues at all.

After about 15-20 minutes of riding, the idle is through the roof. I'm talking about 4.5k-5k rpms. There is no taming it.

I have no idea what the problem is. Yesterday, after getting caught at a few long red lights, I went to stop and the bike completely stalled. I would attempt to start it and the starter switch wouldn't even do anything.

After pushing the bike a few hundred yards, I decided it was too far to push all the way home if I didn't have to and gave it one last shot at starting it. It had been about 4-5 minutes. It fired right up, normal idle and everything. About 5 minutes later when I arrived home, the beast was idling high again, same 4-5K range.

Any ideas?

Only mod is a TwoBrothers exhaust.

 

No, I'm not sure. I actually think that's why it shut off this most recent time.

 

Does the bike have a choke? It could be stuck open as well, which would result in normal cold idle speeds and high warm speeds. It'll also fowl your plugs in a hurry.

 

warren, choke appears to be functioning properly. I can still alter the high idle by moving the choke even when I get the symptoms.

tinkerin,
Temp gauge is up there, about 3/4 of the way up.
The fan is on for sure, I can hear it still going when I turn off the run switch.
Coolant in the radiator? Good question. I had the fairings off the other day and there was coolant in the reservoir. I'm not sure how to check if it's actually in the radiator itself though.

 

Okay, I'll have to check it when I get home tonight. Thanks for the help!

 

Okay, there is coolant in the radiator. How can I diagnose a stuck thermostat?

PS. on cars we would sometimes drill them (in FL we don't freeze) as a semi-permanent solution. Same for bikes?

 

After checking every hose and riding for 15 minutes and after verifying that coolant was indeed flowing, I came across this on the left side of the bike. I turned it and my idle is fine... for now.

Thank you to all that helped me.

 

I agree. I took enough hoses off and wiggled around enough stuff that I think I loosened up some light blockage. Poorly circulating coolant, combined with an idle set way too high could have come together and made for the overheating. I will have everything back together for the weekend ride and post my results.

I still think I have a sticky thermostat and possibly the coolant is just old and nasty. A full flush and new t-stat would probably be a good idea anyway.

 

The idle speed adjusting knob ??? Don't people read the owners manual any more ??

 

Agreed, if the idle was whack right from startup it would have made more sense.