/7 carb question

[jischr]

I've just completed rebuilding the Bings, setting the valves, and checking the timing. I went out for a 10 minute ride before making idle adjustments and about 5 minutes into it the engine would not drop back to idle, just hung around 3,000 rpm. At 10 minutes I stopped, turned it off, restarted (at normal idle), and adjusted the mixture screw and idle screws for a 900 rpm idle. The left carb was almost a half turn higher on the idle screw than the left. Would that cause the initial hang-up? After the adjustments were complete I did city driving for a half hour without a repeat of the sustained high idle so I'm declaring it corrected. But I would like to know what the other possible causes are.

BTW, who ever suggested removing the air intake horns from the air box - good idea I think. I made too many changes to say it was the main contributor, but this old airhead is a whole different machine. Wish I did all this two years ago when I first got it.

Thanks

John

[20774]

What sort of initial settings did you give to the carbs before you took off on your ride? Sounds like they were whack and thus the issue on the road. Could be also that the throttle cable was hung up on the input to the carb and "magically" it corrected itself when you stopped to make the adjustments.

From what you've posted, it sounds like the carb overhaul is only half done. You did some minor adjustments, but it doesn't sound like you've properly adjusted, the mixture and idle speed (they affect each other) or the throttle cable tension.

[tvrla]

The difference could be that the butterflies aren't open the same amount. Also, when you did the work on them, were the butterflies centered in the bores?

The high idle problem is normally caused when the carbs aren't set with a completely warmed up engine.