Idle question

[Del Tysdal]

When I start the 1978 XS 11 it will idle about 1100. After running for some time it idles at about 2000 and will not go down. Why? Thanks.

[Ken Talbot]

With your carbs properly sync'd, with no vacuum leaks anywhere, you should be able to set the warm idle back to where you want with the idle adjust screw. If it is then a bit too low for your liking before it warms up, that's what the enrichener is for. Unsync'd carbs can tend to display the kind of behaviour you describe.

[XSPastor]

More info needed. When you start it and it idles right away at 1100, is the engine cold? Is the enricher on? half or full?
If you start it with the enricher on, then it will run higher than the warm idle until you bypass it. If you don't need the enricher to start it when it's cold, you're probably running too rich. What do the plugs look like? Is this a recent development? The simple answer, if all is adjusted correctly and the enricher circuit (some call a choke) is working correctly, is that your idle is set too high.

[XSPastor]

You're too quick for me, Ken!

[Del Tysdal]

Synching carbs

I will do so. And thanks.

[oseaghdha]

Carbs are dirty

Had the same problem after bringing mine back to life from a 16 year coma.
Either the pilots or the small passages in the bowls seemed to be the culprit.
I had a major sediment problem with the fuel tank and experienced this issue about every two months the first summer I had it back running.
You can chase it around and try to adjust for it, but it wont be right until you R&R the carbs.