Idle change

Yamaha 1100 vstar silverado 2005 I was driving ok then all of a sudden my idle was racing higher when I stop at a light. Checked the throttle and cables they are just fine. Had to turn the idle adjustment way down and it behaves ok now. Does anyone know what might have taken place and why?  

Have you tried running some carb cleaner thru the systerm? From what I found, 2005 has carbs. You may have ended up in a too lean condition, which for reasons I don't quite understand sometimes makes the idle run high. Blipping the throttle when it's idling and having it settle down is a symptom.

Most bikes run too lean at idle (from an engine performance basis... not EPA). So, if the cleaning changes it (may make it worse at 1st... your idle may drop suddenly), the next step is to go thru and adjust the jets in your carb (motorcyclecruiser has it in the tech section).

Other possibilities are some sensor got fouled, and is sending bad signals to the computer... even my  2000 800cc had a computer controlling the carb, and the timing.  

I found the problem. Behind the carbs was a little brass nipple and it is supposed to have a rubber plug over it. Once I did that the bike worked fine  

Probably letting a little extra air, noticeable at idle, but too small to affect performance while riding. I'll have to remember that one.

Although, it does make me wonder. They don't usually put useless openings on a carb. You may want to look if there's some kind of blow by plumbing that got messed with. It could be where the oil fumes were supposed to be sucked back into the carb to be burned. You may want to check, you could be leaking oil from the other end.  

I have a '99 V Star 1100 Custom and two thing to consider also (along the lines of the carb cleaner) is I run about 4 oz. of Sea Foam once a month during a fill-up. Also, the plug you mentioned...is that around the ECU? The guy I bought my bike from had aftermarket pipes installed but didn't plug the ECU output or input ports (yeah, I'm pretty technical?!?) and it ran rich and popped an backfired almost at will. Had my local bike shop look at it, they rejetted the carbs according to the specs for the pipes (that hadn't been done), plugged the ports and it runs great. Don't know if any of that matters now that you've found your problem but something to consider in the future.

Ride hard, watch out for cagers on cell phones, and thank The Man Upstairs for every safe ride!  

Yamaha shows it plugged and I believe its used for syncing the carbs.