Airscrew Adjustment to fix off-idle stumble and Throttle Body Sync - w/ pigtails

[Checkswrecks]

A bit of help please.
I did the air screw adjustment and throttle sync last week and was over the moon with the results.
I set out on a 450mile up to the Scottish borders three days since and it was running perfectly, however over the three days it has started to stutter again and has deteriorated to the point where it now stalls at junctions.
Any ideas, can someone point me in the right direction?

The caps which plug the throttle body ports can crack or get loose. The description seems to fit so I'd start there.

 

[big dave]

The caps which plug the throttle body ports can crack or get loose. The description seems to fit so I'd start there.

My first thoughts, but a quick look under the tank on my return home and both look well.
Do the air screws ever move, unlikely I know but I want to eliminate things I may have caused by last week's adjustments

 

[Checkswrecks]

My first thoughts, but a quick look under the tank on my return home and both look well.
Do the air screws ever move, unlikely I know but I want to eliminate things I may have caused by last week's adjustments

I've never seen the air screws move on their own.

 

[mebgardner]

My first thoughts, but a quick look under the tank on my return home and both look well.
Do the air screws ever move, unlikely I know but I want to eliminate things I may have caused by last week's adjustments

Since the problem started and got worse over a course of days, from what was an acceptable running cycle to begin with (I think that's true, but you don't state it), it's something you did to change it.

It reads like you've got a vacuum leak now. Find That. Look at the things you've touched.

 

[2daMax]

How's the idle speed? Check the left side TB cap. Could be cracked. If the gas tank vent hoses got pinched it will cause the fuel to struggle past the pump.

 

[Xt1200zsupertenere]

Read all 34 pages ::008::

I am about to do TBC ... have got more engine wibes and ingreased fuelconsument ::007::
Have ECU unleash and ARROW headers. ...
yamaha workshop Done all service Sins new ( 2011 , bought it " new " 2013 and
Now run it 4 years 24 000 Miles )

Dont know if workshop Done the TBC : :

The 3/4 airscrew , it is sopose to be Done on europé modell ? ( mine is )
Does is get RICHER or LEANER air / fuelrailen mix by this mod ?
Already have +3 in CO settings

 

[Xt1200zsupertenere]

Hello ,I am writing from Italy and I apologize for my english.I would like to ask you ,when you have syncronized the trottle body,have you cheked the levels of depression with a good instrument?Because the service manual says that the levels could be between 26,5 and 29,5 cm hg and after having unscrewed of 270° what are the values? Then I inform you that when the bike have runned for 20000 km you need to clean the throttle body before make alignment . Regards from Italy

About 27,0 on mine after 3/4 turn on right screw on MINE

 

[Xt1200zsupertenere]

Re: Re: Airscrew Adjustment to fix off-idle stumble and Throttle Body Sync - w/ pigtails

Because we Europeans told everyone so.

Not mine ! ( Sweden ) ... right screw aout 1/2 turn , left ( WHITE paint ) all closed ...

 

[Xt1200zsupertenere]

Should work fine I would think. I have not played with the settings on the ST yet, but my Morgan carbtune seemed to work fine on the DL1000.

Works great ... i usel it yesterday ... worked perfekt ( as long you have read Manuel and put in the clear plastic in Tubes )

 

[RonH]

From what I've gathered, the standard is fully seated, then the other screw is turned out to sync.

 

[IrishST10]

Hello does anyone still have the stumble after the TB sync?

 

[Fortech]

Hey there! I’m performing the 3/4 turn on my 2012 with 20,000 miles as part of my spring maintenance. The TB’s have never been checked since the bike left the factory. I haven’t noticed much stumble off idle on a regular basis but the bike has oddly stalled on me a few times here and there.

I don’t have a sync tool, so made a crude manometer. I used tubing with an inside diameter of 0.17”. I also used a small T but unsure of the inside diameter of it, but it is much smaller than the tubing. Just wondering if this would affect accuracy?

The right screw (white) was seated all the way in. The left screw was ~ 3/4 of a turn out from the factory. I hooked up my newly made manometer to find the TB’s we’re not in sync (assuming the manometer was operating correctly). The left screw required another 1/4 out to bring the TB’s in sync.

I’m probably worrying for no reason, but am now doubting the accuracy of my manometer. I made sure all connections were tight and sealed. What is the probability that the TB’s were out of sync 1/4 turn from the factory and/or over the course of 20k miles?

 

[GSequoia]

Cool. Good to know that it may be either airscrew that is painted as the "standard setting".
I was happy with the improvement too. Try the CO adjustment too.

Hello there. Thanks for this thread, I'm going to try re-baselining my 2016 CA model when I what I suspect is the first TSB (Bike has 8500k now, I bought it at 29xx). I do notice a stumble that is at times pronounced, it hasn't stalled on me but has come close.

What is the CO Adjustment? I haven't seen reference to that earlier. I did see your other thread about grounding out the green wire on the lean sensor, I'm not sure that's relevant on a gen II but I can find out.

 

[Clawdog60]

Will breaking the paint on the air screw cause warranty problems?

 

[eemsreno]

Hello there. Thanks for this thread, I'm going to try re-baselining my 2016 CA model when I what I suspect is the first TSB (Bike has 8500k now, I bought it at 29xx). I do notice a stumble that is at times pronounced, it hasn't stalled on me but has come close.

What is the CO Adjustment? I haven't seen reference to that earlier. I did see your other thread about grounding out the green wire on the lean sensor, I'm not sure that's relevant on a gen II but I can find out.

On 2014 and newer - Only dealers can adjust the co. for you.
It will take about 30 minuets at the dealer.
Has to be connected to Yamaha's web sight.
I'm running mine at +45
they come stock at 0
Made it a lot smother .

 

[GSequoia]

On 2014 and newer - Only dealers can adjust the co. for you.
It will take about 30 minuets at the dealer.
Has to be connected to Yamaha's web sight.
I'm running mine at +45
they come stock at 0
Made it a lot smother .

That's a pity. I don't know if there are any dealers in my area that would play ball with something like that. I bought mine from a BMW dealership so no help there.


Would having a Yamaha Diagnostics Tool handle it? I haven't really done the research yet to see whether it's worth the high price tag. I have no problem spending on quality tools (just dropped some down on a Carbtune out of England for the TBS job) but do like to ensure they're actually worth said money, first

 

[Clawdog60]

CO?

 

[eemsreno]

No tool will let a customer log onto Yamaha's dealer only web site.

 

[siroco]

Can you explain me how the secondary air works?
Is this air burned into the cilinder? Or, is the Air sent directly to the exhaust headers?

 

[ckbikelove]

CO Diag mod

What is the "CO Diag mod"? Link?