Unbalanced Throttle Bodies Only At Idle

[chaoselephant23]

So I hooked up a CarbMate TS-111 to my 2003 California Stone Touring to check the throttle body balance. Adjusted zero on the CarbMate until the middle green LED was the brightest it could be. Set CarbMate resolution to 0.5 cm HG. Turned engine on. At idle, the TBs are out of balance towards the RH side by +2 or 1cm HG. When I rev up the engine, the throttle bodies are magically balanced. I mean spot f******* on! Middle LED burns bright green as it did when the CarbMate was adjusted to zero.

Does this behavior indicate that the throttle body is indeed out of balance? Or do I have a mechanical problem that needs to be addressed? Not into the idea of trashing what may actually be a balanced throttle body because of something else.

Some recent history:
* Performed the CAM recall procedure
* Removed FI cans and sent for a cleaning
* While FI cans were out for cleaning, I cleaned the throttle body assembly inside and out making sure to keep the TPS sensor out of the line of cleaning spray!

[guzzisteve]

Yes, You have a mechanical problem, the cyl with the least vacuum needs to be turned up at idle. Just nudge up the idle speed screw on the lower side. You need a 2.5 mm allen, turn till it matches the other. It doesn't change the top end setting.

[Kiwi_Roy]

The Air bleed screws are like small throttles, they have no effect on wide throttle openings but quite significant at idle.
Actually a couple of cm Hg is not that much.

[chaoselephant23]

Thanks everybody! Hopefully the weather will play nice tomorrow so I can make the adjustment.

Now would the unbalanced idle speed account for all the lugging I am facing at low speed? or do Guzzis need to go fast? I'm just starting my riding career so it's slow laps around the neighborhood in first. But the bike does not sound happy below 20mph. For instance I'll pull the brakes to go around the tight bends that are littered with cars on the right side, bike will get down to 10mph then when roll on the throttle it'll chugga chug until it goes above 20 mph.

[fotoguzzi]

Yes, You have a mechanical problem, the cyl with the least vacuum needs to be turned up at idle. Just nudge up the idle speed screw on the lower side. You need a 2.5 mm allen, turn till it matches the other. It doesn't change the top end setting.

won't that put the connecting rod in tension? I'd start with the air bleed screw..

[fotoguzzi]

Thanks everybody! Hopefully the weather will play nice tomorrow so I can make the adjustment.

  bike will get down to 10mph then when roll on the throttle it'll chugga chug until it goes above 20 mph.

your still in first gear right? at that speed you might need to feather the clutch some.. and yes these motors like to rev.. generally shift above 4k rpm and don't be afraid of revving it out to 7500, limiter engages a bit over 8k.

[Kiwi_Roy]

won't that put the connecting rod in tension? I'd start with the air bleed screw..

Isn't it like an EV with the throttle cable on a drum mid way between throttle bodies?

[fotoguzzi]

your right Roy, I forgot there are two sync rods. as long as that rod connection is also changed when you set the idle stop screw it should be good.. I atill think it's an air bleed fix tho.

https://www.youtube.com/watch?v=gVTiUqw8hew

[chaoselephant23]

Aha! Now I can put a name to that technique. I noticed that a slight pull on the clutch helped to avoid the lugging. Just didn't think that was kosher motorcycling techinque. Guess its time to re-read the Beginners Rider Course materials. It was five years ago. And I haven't gotten the chance to ride since then. I am currently reading David Hough's Proficient Motorcycling.

Found the air bleed screws. Was hoping that Windows 10 would play nice this morning after all the fiddling I did with drivers last night. Still no luck getting GuzziDiag or the IAW15xReader to communicate with the ECU. Ideally I would like to adjust the air bleed screws with GuzziDiag hooked up so I can make sure the idle speed is within the accepted range. But I know I'll probably just wing it with the CarbMate, then come back to it once Windows cooperates.

[Kiwi_Roy]

your right Roy, I forgot there are two sync rods. as long as that rod connection is also changed when you set the idle stop screw it should be good.. I atill think it's an air bleed fix tho.

https://www.youtube.com/watch?v=gVTiUqw8hew

I agree it should be just a matter of the air bleeds, they have more effect at idle.
 

[chaoselephant23]

Got a chance to balance the throttle body with the air bleed screws. Much much better idle now! Noticeably different sound. Rides much better through the low end.

Still facing off against getting Windows 10 working with GuzziDiag. AdapterTest works. But reader or GuzziDiag can never connect. I on the hunt today. Gonna get me some whilst the rain comes down.

Thanks again everybody. Ride well y'all!

[JBBenson]

I have a V11, I think the throttle set up is similar. This is copied from my post at V11lemans.com

Having done it every which way, and having struggled to get a smooth idle, I would:
 
1.
Back off the RH throttle stop. Unless you have some super high mileage bike where everything is worn out and sloppy, using both will make you crazy.
2.
Open bleeds one turn each. ("Micha's method") 1 turn is almost always right.
3.
Sync using white knob at idle. Like I said, some frown at this. Guess what? If they are synced at idle, it will be synced off idle.
 
When the throttles are open (>3k) the white knob needs to be moved a lot to make any difference in vacuum. This is because the small adjustments the white knob makes gets lost in the large flow of air coming through, and tiny imbalances in throttle vanes will be hard to see on any kind of meter, even the expensive one I bought.
 
You can turn the white knob and the throttles will appear to be in balance at higher RPM's. But they're not, which you will see when it drops to idle. Then you can use the bleeds to try to even it out, which is what I did, and then it idles worse than ever.
 
In short, the ultra tiny differences in throttle openings will be revealed at idle but will be lost at higher RPM's. If the idle is balanced, then higher RPM's will be balanced too.
 
Try "JB's" method, and sync the throttles at idle using the white knob. Turn 1/8 and blip throttle and let it settle. Keep doing this until it smooths out and is in balance. The idle will probably creep up as it smooths out (you can adjust this later using the LH throttle stop screw). It will never be perfect but you can get it close. Check "off idle" RPM's as you get it smoother, I bet they will be in sync too.
 
Yes, this method is backwards, but since your bike runs like crap right now, why not try it? I went through ever "method" before doing it this way, and now my bike runs like a sewing machine and pulls like a locomotive. The idle is steady at an indicated 1500, with small fluctuations due to ambient temperature, or certain trailing throttle situations, which i think is an ECU issue if anything (I am running modified ECU map).
 
I ended up buying this:
 
http://www.amazon.co...r/dp/B0022XTDQA
 
Guess what, the simple manometer is just as good: http://www.powerchutes.com/manometer.asp

[Wayne Orwig]

I have a V11, I think the throttle set up is similar. This is copied from my post at V11lemans.com

The V11 Lemans is a good bit different than the EV/California, which I believe the OP is talking about..

[chaoselephant23]

...
In short, the ultra tiny differences in throttle openings will be revealed at idle but will be lost at higher RPM's. If the idle is balanced, then higher RPM's will be balanced too.
...

That ↑ makes the post!

Finally got GuzziDiag working. Turned out to be user error during connection brokering. Going to elucidate on my issue in the GuzziDiag thread.