Adjusting Idle

[al_roethlisberger]

Ok, maybe this seems like a bone-head question, but this ain't my old carb'd FJ1200

 

Anyway, my bike is currently idling too high. I think the shop set the idle a bit higher than normal waaaay back when we were having all the idling problems, later solved by a valve adjustment.

 

But for the life of me, other than tweaking with the bypass screws, I'm not sure how to adjust the idle down to ~1000/1100rpm

 

Right now it's closer to 1500 or a tad more according to the Vague-lia

 

Anyone have a step-by-step procedure that I can do at home, that doesn't throw off CO % or other settings as well?

 

thx!

al

 

 

P.S.

 

The stop screws are all the way out on the Throttle Body stops already, so they aren't setting idle.

[callison]

Al, my Mike Rich heads are doing the same thing. Must be something about airflow efficiency. Nothing I've tried drops it below 1500 rpm.

[al_roethlisberger]

....hrmmm <_>

 

I guess it's not the end of the world, but it's a little disconcerting since I'm used to the 1100-ish idle

 

Anybody else? Maybe when it goes into the shop for engine case replacement they can put it on the computer and tweak it. I don't guess I can controll idle with the PCIII can I?

 

al

[dlaing]

I guess the only thing to do is to tighten the valve adjustment.

I hope you don't have to go tighter than US specs.

Perhaps the TPS could also have an effect as it may change the ignition advance.

Al, did the RPMs pick up after the second plug was connected?

Carl and Al, 1500RPMs!!! That is efficient!

[al_roethlisberger]

...naw, it's been high ever since last Spring, but I'm just now really looking into it since I'm going to get it remapped soon.

 

The RPM didn't change when the second plug was "engage" as far as I noticed.

 

al

[roberto]

I don't think you can do anything without mucking up the CO levels. You can adjust the fuel at idle with the powercommander (0% throttle) and then adjust the CO with the bypass screws. If the CO is ok just now and the throttle stops are backed right out you are getting too much fuel AND air.

Note that during a typical tuning link procedure, the powercommander is zeroed at the throttle position when resting against the stop screws. Backing out the throttle stops after tuning would cause a TPS reading to the PCIII that is "off the map" (less than 0%). I don't know what that would do, but it's not recommended.

Check that there are no leaks in the intake rubbers, etc - a lean mixture could cause the idle to run higher.

A temporary fix (to lower the idle) would be to screw in the air bypass screws while vacuum gauges are attached to richen the mixture too much and drop the iddle speed (better too rich than too lean). As long as you don't spend too much time at idle, the plugs will clean up as soon as you are above 2500rpm.

BTW - get rid of the RH throttle stop screw - it is impossible for them both to function - I removed the RH one so that a TPS check could be done without mucking up the idle setting - you just undo the linkage at the ball joint and the RH throttle will fully close. After measuring TPS output, reconnect the ball joint - nothing will need adjusted.

[docc]

Good advice from Roberto on defeating the RH idle screw. And also to be sure your rubbers are not leaking. ( never good )

 

Be sure to check that the high idle cam on the RH TB is not fouling the linkage. Release it completely to see if the linkage will then come to rest on the LH TB idle screw.

 

The 'high idle' ( or "choke") is most likely acting as the throttle stop.

[Lex]

This is another reason why I enjoy this place. My idle has been getting higher since my bike started breaking in and I eased the restrictions in its breathing. At first the left hand adjuster had an effect then it stopped working. I never thought to look for an adjuster on the right TB, I've never seen a second adjuster on a properly linked (i.e. non-BMW R259) FI system. I looked everywhere else (fast idle linkage, etc.) and never saw the (very well hidden) adjuster on the right TB. Thanks to Roberto I now have a nice, smooth 1100-1200 RPM idle.

 

Thanks Roberto!

 

Cheers,

 

Lex

[docc]

I was eternally grateful that someone at Moto Guzzi had the vision to paint all the pertinent adjusting screws with that thick yellow paint ( is that US only??). It was the only way I could find all the screws that needed to be moved!