Fixing the low idle on a 2006 Ducati Monster 620

[CaLyPsO]

I am currently helping my niece with her 2006 Monster 620 which has a very low idle and keeps stalling out. The idle is sitting right around 850 RPM and I am having a hard time getting it to respond to the air bypass screws. I have already gone through the synchronization and set the throttle position sensor to the standard 150mv baseline and 2.7 degrees for idle but nothing seems to raise the engine speed. When I open the bypass screws I can actually hear the air moving but the RPM stays flat and the bike still smells like it is running too rich. It seems like the mechanical settings are correct so I might be overlooking a sensor or a vacuum leak somewhere in the Bing throttle bodies. I can use the fast idle lever to hold it at a steady 1100 RPM and it runs fine but that is only a temporary fix. I am hoping to find the real reason why the bypass screws are not making a difference so she can enjoy a reliable ride.

 

[black bear]

I am currently helping my niece with her 2006 Monster 620 which has a very low idle and keeps stalling out. The idle is sitting right around 850 RPM and I am having a hard time getting it to respond to the air bypass screws. I have already gone through the synchronization and set the throttle position sensor to the standard 150mv baseline and 2.7 degrees for idle but nothing seems to raise the engine speed. When I open the bypass screws I can actually hear the air moving but the RPM stays flat and the bike still smells like it is running too rich. It seems like the mechanical settings are correct so I might be overlooking a sensor or a vacuum leak somewhere in the Bing throttle bodies. I can use the fast idle lever to hold it at a steady 1100 RPM and it runs fine but that is only a temporary fix. I am hoping to find the real reason why the bypass screws are not making a difference so she can enjoy a reliable ride.

Have you checked the engine temperature sensor and its wiring since a faulty reading can cause the ECU to dump too much fuel at idle?

 

[jeeperkeeps]

You should look for any cracks in the rubber intake boots between the throttle bodies and the engine that might be leaking air.

 

[n0tlike0therdrivers]

Does the idle speed change at all if you use a can of starting fluid to spray around the base of the throttle bodies while it is running?

 

[lavend3r]

@CaLyPsO It is a good idea to ensure the spark plugs are fresh and gapped correctly because fouled plugs will make a low idle even more unstable.

 

[CaLyPsO]

It sounds like this lever just opens the throtle a little and isn't actually a choke. I don't see any sensors connected to it that would tell the computer tto adjust for a cold start. Am I missing something?