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

[eemsreno]

Steve, did you also jump the clutch safety switch? What is your average fuel mileage?

Tomatocity
I have a switch for the CJM but never use it.
On our trip to Hyder this summer the bike had 44.6 on the dash when we got home loaded like this.

 

[Maxified]

Just got through checking the TBS with the Harmonizer and discovered that the little rubber nipple cap on the right side covering the vac port was developing a crack. Did not appear to be leaking air yet but probably soon would have at some point. Another item to note on for the routine maintenance check list...

 

[fredz43]

Just got through checking the TBS with the Harmonizer and discovered that the little rubber nipple cap on the right side covering the vac port was developing a crack. Did not appear to be leaking air yet but probably soon would have at some point. Another item to note on for the routine maintenance check list...
[/quote

Yes, I had the same thing on my 2012 model. Found it when I was looking for possible sources of the fast intermittent idle that suddenly appeared. A new vac cap cured that.

 

[tomatocity]

Fredz43 - "Yes, I had the same thing on my 2012 model. Found it when I was looking for possible sources of the fast intermittent idle that suddenly appeared. A new vac cap cured that."

Good to know. I noticed a fast intermittent idle while riding on Thanksgiving Day. Did you replace the caps or do something different? I have been using small pieces of fuel hose with clamps and a metal plug in the open end. Time to replace the pieces of fuel hose.

ee - The dash is usually high but you are still over 40 mpg and that would be very good with that load. Easy on the throttle. I am surprised no one challenge you on the +20. I don't understand that setting but thought the higher the number the worse gas mileage. You are getting 40+ with a heavy load... very good.

 

[eemsreno]

[quote
ee - The dash is usually high but you are still over 40 mpg and that would be very good with that load. Easy on the throttle. I am surprised no one challenge you on the +20. I don't understand that setting but thought the higher the number the worse gas mileage. You are getting 40+ with a heavy load... very good.
[/quote]

Tomatocity
The good think about trying this +20 think is it is free and easy to go back if you don't like it. I never found it to effect my fuel millage at all. I am easy on the throttle when Michelle is with me and we stayed off interstates which makes a big difference. When we go blacktop road riding down in MO. at 55 or slower the dash will go up to around 50 mpg . Out here in this frozen tundra this time of year if I just commute to work 10 miles one way the dash will really go down, 35 mpg would be common. The bike barely gets up to temp in 10 minuets of riding though.

 

[Checkswrecks]

[quote
ee - The dash is usually high but you are still over 40 mpg and that would be very good with that load. Easy on the throttle. I am surprised no one challenge you on the +20. I don't understand that setting but thought the higher the number the worse gas mileage. You are getting 40+ with a heavy load... very good.


Tomatocity
The good think about trying this +20 think is it is free and easy to go back if you don't like it. I never found it to effect my fuel millage at all. I am easy on the throttle when Michelle is with me and we stayed off interstates which makes a big difference. When we go blacktop road riding down in MO. at 55 or slower the dash will go up to around 50 mpg . Out here in this frozen tundra this time of year if I just commute to work 10 miles one way the dash will really go down, 35 mpg would be common. The bike barely gets up to temp in 10 minuets of riding though.

I'm willing to be corrected on this, but as far as I know the CO setting ONLY affects idle. That means you have massively richened your fuel air setting at idle and it should have no affect while riding.


Don't get me wrong, in that I'm glad your problem seems fixed. But needing to go that rich leaves the question about why the need to so massively richen it at idle? There is an implication that you MAY still have a small air leak somewhere. The next time you have the tank up, let it idle for a while and then compare your spark plugs. That much of a difference ought to show. You may also want to look around the edges of the air filter and see if you have a general leak in the air box, or if maybe the little plastic drain in the back left corner is missing?

 

[eemsreno]

After over 25,000 miles of testing this I am sure there is no air leaks anymore.
And what the RTA said + 20 is not over rich it's where it should be.

 

[fredz43]

Fredz43 - "Yes, I had the same thing on my 2012 model. Found it when I was looking for possible sources of the fast intermittent idle that suddenly appeared. A new vac cap cured that."

Good to know. I noticed a fast intermittent idle while riding on Thanksgiving Day. Did you replace the caps or do something different? I have been using small pieces of fuel hose with clamps and a metal plug in the open end. Time to replace the pieces of fuel hose.

Tim, it was only the cap on the right side TB that was cracked, so I replaced it with another rubber cap and all was fine.

 

[tomatocity]

Thanks Fred.

--------------------------------

A hundred years ago I was taught how to check for vacuum leaks. Use water in the solid liquid form and not spray. Apply the water and if the rpms increase you have found a vacuum leak. Using the spray water could be misleading where the vacuum leak is.

 

[Mzee]

I noticed that Co2 calibration also affects engine vibration. I set it at -5 and my engine vibrated more, then I set it at +2 and my engine vibrated less.

 

[lbever]

After over 25,000 miles of testing this I am sure there is no air leaks anymore.
And what the RTA said + 20 is not over rich it's where it should be.

I was at Hicklin Powersports open house last Saturday, to my surprise eemsreno walks in. I had mentioned how happy I am with my Tenere after I had Flash-Tune re-program my ECU. At which point eemsreno told me how well his +20 adjustment worked. So I had to take his bike for a ride so I could compare it to my re-flashed bike. I have to say it is really good. Dead spot is gone an it runs very smooth. We both have replaced the clutch hubs so it was a good comparison. Only thing that I really noticed was his bike still had the throttle lag that mine does not haven since it was flashed. I would recommend trying the +20 adjustment is you are not wanting to pay for a re-flash.

 

[eemsreno]

Thanks for the write up Larry.

I should have flipped the CJS on before you took it out. With that on it really feels responsive to me.
I know how you like to use the throttle
.I must be used to any throttle lag " at my age I probable need all the throttle lag I can get"
It's the smoothness and lack of power dip and just plane good running that I like. NO MORE SURGING!!!

 

[BAD65]

Thanks eemsreno for suggesting the +20 on the CO setting. I just got a new 2013 and opened up the airscrew and set the CO to +6 like everybody else. After reading his suggestion of +20 I spent a day experimenting with CO settings at 20, 17, 14, 10, and 6. At 6 the low RPM stumble when letting the clutch out is gone like others have reported but the lean condition at 3000 to 4000 RPM is still there. I had to get it up to +17 and then the higher RPM lean spot is gone and it runs much smoother without lean vibration feel that I had thought was inherent to this engine. At +20 its even better at 3 to 4K but its starting to get a little rich at idle but not to where feels bad. I read about how the CO settings work on another forum and it said that the setting adds a fixed amount to the fuel injector pulse width. That means at higher loads and RPM's, the effect is diminishing but that's good because it will have the most effect at low load and RPM where they have leaned it out for the EPA test. +17 to 20 gets the setting up high enough that you finally impact it at 3 to 4K RPM but will also be getting on the rich side for the lower RPMs. It runs great now and I am pretty sure its not to rich at idle but I will check the plugs to make sure.

Thanks eemsreno and the Yamaha tech who suggested this.

Regards,

Brett

 

[nhdiesel]

I had the rough idle and sluggish low RPM performance since picking my bike up last week. With around 900 miles on it as of early today I did the air screw adjustment. WOW! What a change! Smooth idle and smooth low speed performance. This is how my bike should have run from the dealer. Thanks for the how-to!

 

[itlives]

I'm changing my air filter and just getting to know "Chatterbox". Looking at the first pic in this thread, there is a vacuum hose directly below the white screw.
What is that for? Mine is capped off.
My bike was ridden by the owner of the local dealership for a year. I probably need to ask him a few questions like- where is the centerstand!?

Edit- anyone??
To add - I backed the screws up just enough so they weren't bottomed out. (Probably 1/16 of a turn). It helped the low end stumbled immensely.

 

[CurtC]

When I first got my 2012, it had a wicked off idle stumble. I sent the ECU away and had AVC flash it, cured the off idle stumble, other big improvements also, thought I was done. But over time I've still not been happy with the low speed smoothness, throttle was still very binary, seemed just lousy at idle to 2000 rpm speeds.

Last weekend I opened the air screw 270 degrees and sync'd with a harmonizer (it was previously screwed all the way in). Wow, night and day difference, much smoother low rpm transitions, much smoother at low speeds off road etc.

Just another data point, worth doing even if flashed IMO

 

[Anwar Namtut]

Anyone in the Boise area want to help me out with this?

 

[Bug Dr.]

I just changed spark plugs, air filter, oil filter, final drive oil, did the airscrew adjustment, throttle body synch (with Harmonizer) and the CO adjustment (+8). Wow! The bike is so smooth now it feels like a new one. I can't believe how this smoothed out the vibes that had been getting worse. The throttle bodies were +25 mbar out of synch.

I left a pig tail with a quick connect to the green wire on the tip over sensor so I can tweak the CO if needed. I will go for a longer ride tomorrow with bigger hills to see if it still chugs some.

Thanks for all of the pics on this thread and the CO thread.

FYI: 2013 Tenere with 17K miles

 

[Tempesc]

Can i ask a dumb question?

I thought the fuel mix is controlled by the ecu. How does that work with an airscrew then?

 

[Spaggy]

The airscrews (one on each side) balance the throttle bodies, turn the right one out 3/4 turn from bottom and balance with a harmonizer or similar. I modded mine with the extra vacuum hose left on each side to make it easier to check balance. The extra volume in those little hoses made my bike run weird. When heavy on the throttle passing, my engine light would flash, my cruise would flash and need resetting and had a stumble at 5-6000 rpm. I removed the extra bits and everything works perfectly now.