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

[Reveille]

I made a quick post on how to do your own cheap and easy TB sync tool. Should be right below this one for now but here is the link:
http://www.yamahasupertenere.com/index.php?topic=11622.msg190629;topicseen#new

Thanks. ::008::

 

[fredz43]

I may just take you up on that. It takes me at least that long to pull the side covers and pull the tank. You must be fast. ::024:: Springfield is 2 hours so you would be a 3 hour ride I recon. I am in the Yorkville area.

Part of it is I show you how to raise the tank without taking the left side cover off. ;D

 

[Reveille]

Part of it is I show you how to raise the tank without taking the left side cover off. ;D

I am game. The best time for me would be the weekend of the 17th. I have a long gravel ride weekend the last weekend of May. Maybe I could talk you into coming up for it? It is called the great river gravel ride. Hosted over on ADV. We leave out of Iowa and head up into Minnesota and Wisconsin ending up back in Iowa. It would be nice to get things sorted before this ride. Are weekends good for you or?

 

[fredz43]

I am game. The best time for me would be the weekend of the 17th. I have a long gravel ride weekend the last weekend of May. Maybe I could talk you into coming up for it? It is called the great river gravel ride. Hosted over on ADV. We leave out of Iowa and head up into Minnesota and Wisconsin ending up back in Iowa. It would be nice to get things sorted before this ride. Are weekends good for you or?

I am retired, so any day of the week is a weekend for me. However, the weekend of the 17th is our local dealer, Niehaus Cycle Sales' (www.niehauscycle.com) annual Appreciation Days open house. I work part time there occasionally as my retirement job and always work that weekend. There will be probably 4,000-5,000 bikes in town for that and we'll have Yamaha and Honda demo rides., among other activities.

 

[tomatocity]

Fred are you going to show everybody how to remove the tank without removing the left side? :lamp: ::26::

 

[fredz43]

Fred are you going to show everybody how to remove the tank without removing the left side? :lamp: ::26::

hi Tim,

I have posted my method before, but I'll repeat it. I only remove the 3 rear left side panel screws and then am able to pry the left side panel out enough to remove the tank bolt. The key to making it easier though is to replace the allen head tank bolt on that side with a 6 mm bolt with 10 mm hex head. Then all I have to do is reach in with my 10 mm ratcheting box end wrench and spin it out of there. In 32,000 miles of ownership, I have never removed the left side panel.

 

[tomatocity]

hi Tim,

I have posted my method before, but I'll repeat it. I only remove the 3 rear left side panel screws and then am able to pry the left side panel out enough to remove the tank bolt. The key to making it easier though is to replace the allen head tank bolt on that side with a 6 mm bolt with 10 mm hex head. Then all I have to do is reach in with my 10 mm ratcheting box end wrench and spin it out of there. In 32,000 miles of ownership, I have never removed the left side panel.

The last time I sync'd the TB's I took your very good advice and replaced the tank bolt. Last Sunday we sync'd the TB's and I removed only two of the rear side cover screws. Tight getting to the tank bolt but I remembered the third cover screw was a PITA. As I was finishing installing the last cover screw I remembered reaching behind the bracket and pushing out helps align the screw. Next time I will remove the third screw and make it simpler.

 

[Reveille]

I just finished doing the air crew adjustment and sync. Ended up making a home made synchronizer. Worked perfect and I also replaced the left side tank bolt with a hex so I can use a ratchet 10mm wrench so the side cover doesn't have to be removed. Thanks for the tip! I went for a romp and she runs smooth like butta! Very easy and good mod, well worth the time spent. If I can do it, you can too ::024::

 

[fredz43]

I just finished doing the air crew adjustment and sync. Ended up making a home made synchronizer. Worked perfect and I also replaced the left side tank bolt with a hex so I can use a ratchet 10mm wrench so the side cover doesn't have to be removed. Thanks for the tip! I went for a romp and she runs smooth like butta! Very easy and good mod, well worth the time spent. If I can do it, you can too ::024::

Good on ya. Job well done. ::008::

 

[Wistrick]

did the 3/4 turn thingy and bumped the co to +3 and added an Arrow noise maker and she is about perfect now...Oh and I reflashed it about 2 weeks after I bought it..

Dan

 

[Trek]

Well I finally made the air screw adjustment today.
There is less hesitation, but still some.
None would be better.
I'll have to ponder my next move.

 

[Rasher]

One thing I had noticed and I do not think mentioned here, is that with my Gen2 ECU-U flash combined with Arrow headers is that removing (unplugging) the O2 sensors has almost completely removed the slight surge at very low rev / steady throttle, and wondered if this may also help with the stumble for anyone who still has issues after and ECU-U Flash.

I cannot really detect any reduction in MPG without the sensors in operation, and the surge that used to happen at 2000 - 2100 rpm on a steady throttle is now over such a small range it is very difficult to get it to do it now even if trying to, before you could pretty much guarantee it would happen when holding 25-28 mph in 4th, now I can occasionally get it to occur if trying to, but in normal use I am now able to use 4th at 30mph (handy as a very common speed limit in the UK) and if the traffic slows a shade it does not start jumping around (and even if it does now it is barely perceptible as opposed to bucking bronco)


I have now started wondering what is the relationship between the Air Screw / CO / Flash changes :question:

My assumption has always been the Flash should correct any weakness in fuelling that causes the stumble, and am pretty sure the stumble on my bike has gone, or certainly gone in S, I am not sure about T (left alone by the ECU-U Flash) but it may just be the much more sedate throttle mapping makes it feel weak off idle as I feed the power in / clutch out (and I very rarely use T Mode anyway)

I thought the CO was to allow a bit of adjustment to fuel ratio, either up or down a shade across the entire range of revs and throttle settings including the closed loop area.

And finally to the airscrew, I thought these were the same as on carbs and will allow a tiny bit more fuel through that really only affects very low throttle openings / low revs significantly - and therefore is most likely to make the most improvement to the stumble.

I may play with the Airscrew (or get my dealer to as I do not have the tools) or maybe just tweak the CO, but think this may affect the "perfect" fuelling of the flash in the rest of the range.

 

[McBride]

The stumble, is that where the bike when coming up to a stop light or stop sign, the motor will just idle down till it quits running. I have had mine do that several times. It is very irratating. I only have around 500 miles on it and thought I would wait untill the 600 mile check up to have them look at it. It doesn't do it all the time. But it is enough to cause me a bit of concern.

 

[Reveille]

No. The stumble is more while lightly accelerating from a stop and having the bike suddenly lurch without any changes to throttle input. This is a combo of factory built in ECU restrictions and a lack of throttle body synchronization. Or a very lean setting at least. that is my understanding but I may be way off on my explanation...

 

[Mzee]

No. The stumble is more while lightly accelerating from a stop and having the bike suddenly lurch without any changes to throttle input. This is a combo of factory built in ECU restrictions and a lack of throttle body synchronization. Or a very lean setting at least. that is my understanding but I may be way off on my explanation...

If it is this then I don't suffer from this problem.

However this thread has information overload. I can hardly figure out what to do.

 

[Ron_Luning]

If it is this then I don't suffer from this problem.

However this thread has information overload. I can hardly figure out what to do.

The stumble as mentioned by the originator of this thread (Speedstar) is when the engine suddenly dies when going from idle with closed throttle to an open throttle. A good example is when trying to start off from a traffic light. Any other interpretation of what he wrote is not correct. I know this because he and I worked on this problem when the first bikes were delivered to the USA. It was only a matter of time until someone would have rear ended me on a stalled bike, so I made a big stink about it.

I only did what Speedstar wrote about early on in this thread, and it worked to *almost* always let me pull away from a stop cleanly. Note that it was not a matter of not giving the bike enough throttle like a first time rider might do that caused the stalling. Rather, any opening of the theottle would instantly kill the engine....hence the "stumble" because it would fall flat on its face.

I believe Speedstar wrote about his pigtail connectors for throttle body sync as an option to make future throttle body syncs easier. I did not do that.

 

[broncodave]

I had a backfire through the intake and stall almost every day .
Did the simple fixes with little success at 24000 mile did valve adjustments most were tight .
It has only done it a few times since now at 36000

 

[Mzee]

The stumble as mentioned by the originator of this thread (Speedstar) is when the engine suddenly dies when going from idle with closed throttle to an open throttle. A good example is when trying to start off from a traffic light. Any other interpretation of what he wrote is not correct. I know this because he and I worked on this problem when the first bikes were delivered to the USA. It was only a matter of time until someone would have rear ended me on a stalled bike, so I made a big stink about it.

I only did what Speedstar wrote about early on in this thread, and it worked to *almost* always let me pull away from a stop cleanly. Note that it was not a matter of not giving the bike enough throttle like a first time rider might do that caused the stalling. Rather, any opening of the theottle would instantly kill the engine....hence the "stumble" because it would fall flat on its face.

I believe Speedstar wrote about his pigtail connectors for throttle body sync as an option to make future throttle body syncs easier. I did not do that.

Excellent Response. Makes it easy to understand the exact problem.

 

[eemsreno]

This post is just a possible help for anyone with stalling or surging at slow speed. My bike has suffered from this off and on through the years with that dangerous stalling at a stop light when starting to let out the clutch when I first got the bike. Over all it was mostly some annoying surging at low speed riding trails. My bike is all stock with no Flash. I threatened lots of times to have it done when it would stall or surge bad but I was just a little erked that I would have to pay to get my bike to run the way Yamaha should have made it in the first place.
This last spring when I got out of Iowa’s frozen tundra to ride to the Twisted Sisters ride that Dallara hoisted, my bike was running the worst it ever had. When I got home I found that putting zip ties on the vacuum hose to the pressure sensor got my bike running back to normal. I think it was TABASCO way back years ago that said “do not leave the T fitting in the vacuum line for easy TBS”. He is so correct if it was him. This vacuum hose can not have any air leak at all.
But I talked to a Yamaha R.T.A. about the surging and told him all I had done to get it running better. When I said that I had set the CO. to +4 he stopped me and said that the bike wouldn’t even notice +4. He said to try putting it up to +20.
That is what I done and it has been there all summer.
I wanted to do thorough testing all summer on this before I posted on it.
The summer is over and I have over 25,000 miles on this setting so it is time to post about it.
My bike runs so good all summer that I wouldn’t even consider a flash any more. It runs Perfect, No dip in acceleration in T mode, No surging at all, Never stalls. So smooth it’s ridicules.
I let another Tenere rider test it the other day and all he could say is “WOW, That really runs good,, Really good”. It dose and I’d be glad to let any of you try it.
My fuel mileage has always be very good and if this had any effect on it, it could only have improved it as far as I can tell.
I hope this might help anyone out there that is not satisfied with the way there Tenere runs. They can run perfect in stock condition and now every time I ride my bike I just can’t hardly believe it.

Steve

 

[tomatocity]

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