Saturday, April 29, 2023

Multistrada 1000 idling issue - Another (more complete) take on it.

 Some time ago I had a MTS1000 in that had been set up badly to overcome a non idling issue.  That was part of a minor service and not much disassembly, and I got around that electronically.  See here -> MTS 1000 not idling  That particular bike had a very vague history and a couple of dash replacements with no record of actual km.

A bit of MTS1000 info from that report - The MTS1000 was the first Ducati with an idle control valve ("stepper motor", etc).  Any model with an idle control valve doesn't need the air bleeds (the little screws on the sides of the throttle bodies that allow air to bypass the throttle blades) opened, as their primary function is to allow you to set the idle speed.  I also use the air bleeds to equalise the idle mixture between the cylinders, in which case you open the air bleed of the richer cylinder to lean it off to be the same as the leaner cylinder.  Meaning one air bleed should be fully closed.

Seeing air bleeds wound out on bikes with idle control valves really winds me up.  Just not how it's meant to be done.

Recently I had another MTS1000 in for an 80,000km service that I found in the same sort of tune set up - air bleeds wound out one and a half and two and an eighth turns and idle trimmer @ +20.  My response was to wind the air bleeds fully in and set the trimmer to 0 to see what happened, but there was no way it was going to idle successfully.

As I was doing a major service, and had just popped the fuel tank back on to run it, there wasn't a lot of time to be spent pulling it again.  That made it worthwhile to pop off the tank and airbox and have a looksee at the throttle bodies.  As below.




Icky.  But not unexpected for 80,000km, especially on a model where you don't pull the airbox for routine maintenance like you do a Desmoquattro for instance.  None of the 2V models really give you easy access to the throttle bodies to clean them at service.  So I broke out the Threebond Engine Conditioner - which despite the name is a throttle body/intake cleaning spray - and gave it all a good clean up.  I sprayed some down the idle control valve air hose as well, as they can also get claggy.

It's quite awesome for getting fuel residue and combustion gunk off.  I soak carb bits in it, but don't give them too long is my advice.


And Voila!  Lovely.


Back together again, it ended up with both air bleeds still full in and the idle trimmer @ +4, idling happily as desired.



1 comment:

  1. I never knew how crucial the idle control valve setup was. Thanks for sharing!
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