[EastSideCBR]

I have a particularly difficult problem. One day I rode my bike into work and the bike ran flawlessly. Later in the afternoon I went to ride it back home when the first stoplight I came to the bike would not idle down. It stayed at about 3K rpm. After making it home I tore the bike down expecting to find maybe a stuck throttle or idle adjustment out of whack. The throttle works fine (new cables 2 mos ago) and the idle adjustment was where it was supposed to be. I have to admit this has me baffled as to why in a matter of a few hours the bike just decides to idle really high. I have checked all the obvious things like the throttle cables, linkages, air vents, air filer, ran a new tank of gas through it, the choke and the bike had not been sitting having been run the day before. I have found nothing out of the ordinary. I have searched the web looking for information on this, including this site and have found a few others who had the problem or the symptoms I am describing. But no solutions or probable causes were given. So I am asking the good folks here if anyone has come across this or knows what might be the possible culprit. Failing that I may have to admit defeat and take it to the mechanic.

 

[enos]

What do you mean the idle adjustment was where it was supposed to be? The dial doesn't give you an absolute scale..

The other thing might be an air leak. Spray the area between the carbs and engine with wd-40, and see if that makes a difference.

 

[dragracer1951]

I would think maybe a torn intake rubber manifold or an over tightened clamp on same...
It's an air leak for sure
Jim

 

[EastSideCBR]

GOT IT! It was the choke. When actuating the choke off, the choke would not come all the way off. After cleaning the mechanism it finally idled down when warmed.

enos: When I said the idle was where it was supposed to be I meant that the idle wasn't changed at all. The "spraying-the-carb" trick was the first thing I tried.

dragracer: I initially thought it was an air leak as well until I tore it down and found no tears, loose air intakes or vacuum leaks and like I said to enos, The "spraying-the-carb" trick was the first thing I tried.

Thanks for the replies though, as frustrating as it was at first persistance does pay off!!