Whats been the collective wisdom with repeated stalling...?
  I know a few people have posted about their bikes falling below adequate idle speeds and then stalling. Mine is doing it all the time. A reset at the key is the only thing to get it started after..until the next time.
 Its a pain...!
 Im gonna yank the injectors and get them cleaned this winter. I guess I might also be looking at ISC valve solenoid failure or some such, right ?
  Answers on a postcard...!
Grtzzz...

Hi Tim,
this has presumably happened over time?
Run injector cleaner for a good 2 tanks.
I,d reckon you have to check the basics first, hows the aircleaner and are the valves ok.
Throttle body balance, can be checked without removing.

TPS? Wasnt there a recall on the tps?? for this reason?

At the beginning of every season I run a 1/4 bottle of Naphtha through the tank. Then I run the tank empty, then refil. I repeat once more mid season..... Ive been getting a consistent 220km on the highway (at 110-115kph), even 2 up.

BE VERY CAREFUL if you do this. Do not let the fuel naphtha sit in the tank (its more about the hoses/rubber/plastic that it contacts.
Its a very powerful chemical that can weaken rbbr after prolonged exposure.

Naphtha is the main ingredient in the carb/injector cleaner Seafoam.

ymmv

alan

I wouldnt say over time Graeme...It has only just raised it's ugly head after some 90K kms...but how. It prefers to drop the revs and stall out more often than not. It runs fine after a reset (at the key) ...makes me think it's something beyond carb/fueling issues, although a restart at the key initiates a fast idle setting until the ECU has sufficient temp sensor data to allow it to drop onto the ISC valve setting....
  I take from your reply you suspect carby/fueling issues...Its good to know. I will assume this is typically the seat of the issues, as it did seem to get reported on the forum that was, quite regularly....
 Ill do a sonic clean. If the injectors are crud packed, I cant see much future in washing it past valves and try burning it...I mean, where does it go, really ?
 Has no one had to replace their ISC valve...?  I remember pricing the valve for Otto many years ago who hoped it might be cheaper here in the U.K.  but must admit, its my only recollection of the unit and its function...!
 Seems strange it has developed overnight pretty much...
BTW- Graeme, is a throttle body sync covered in the manual to your knowledge mate..?
 TIA for any help !
TimR   

Hi Tim, I would think the last likely suspect is the actual isc. As you say, on restart there is a different setup for a while and it confuses things.
You could be right about the injector(s) but I would first look at the balance of throttle bodies and the idle stop screw.
Vac gauges etc are not used for this. Thats a job after the physical balance is set.
The idle stop screw (the untouchable one) is hard to get at without tank off (or propped up ). Because they dont want you changing it without great care the end is just a square. If you do alter it you must take the bike for a run to be sure of result which is a pain since the tank is off (or propped up)
But I do know that that idle screw take very little change to make a difference and what you describe is exactly what it does when its a little too far out.
I made mine so I could adjust it a little from the outside. As to why it would change. Well that is interesting and I noted that the screw could "settle" a little just by the throttle closing(many times) and gradually "hammering" the end of adjusting screw. If the bike was set at the lower end of the range in the first place that might be enough to push it into the stalling area.
Throttle body balance is a tank off job and get access to the bodies so you can get a feeler gauge down there.
You can see the balance screw between the bodies and what you need to do is put a spacer (dont screw the idle stop) between the idle stop screw to open it a tiny bit then use a feeler gauge to get a neat slide between the butterfly and body. If the bodies are different adjust the balance screw to make them right. The oil tank side is the base of course and you are adjusting the other one to match it. Very small adjust or it might be perfect anyway.
Of course it could be a sensor or something as Nikk says but I think you must check these 2 first as they are the most likely.
If you dextrous with hands you can get to the idle stop screw with a pair of pointy nose pliers or similar and try a small adjust but I found it too easy to not know how much I had turned it. From stall to ok is maybe 1/2 to 3/4 turn of screw.
Since I did mine it has idled perfectly every time. I only had to do it because of fitting 43mm bodies and changing over the stratoliner cable cam etc which are different to MT.
I,m happy to be wrong but would like to know what you find-----------------

  Okay...thanks for patient reply Graeme..!
  Its a job that will likely be left for the over winter period, as annoying as a bike that keeps dying is, especially  when in traffic.
   I simply have too many other pressing projects to get sorted. It sounds a simple enough process, if a little circuitous and repetitive what with tank removal and replace. test , repeat...What I mean is, I probably want to get at it in one a time effort. To keep track of myself and changes. For me, it starts with an injector clean...I guess a tank full of cleaner may be the go...( yikes!! )   I have run the bike dry a couple times now. Perfect scenario for pulling crud into the fuel delivery system, & into unwanted locations, only to become lodged and grow exponentially...! 
  I'll try and report back here my findings. You can bet on it if it turns out to be the ISC itself !!! 
    Having fettled extensively now with 2T carburation...a 1/2 - 3/4 turn seems alot ! I have understood you say that anti-clockwise at the idle screw reduces revs...


  Of course, being a stage 3 bike, there is no closed loop !  Makes it a little more straightforward, in theory anyway.

  cheers   

Well yes, make a whole job of it. Terrific option. Removing the injectors and bodies is ridiculously easy once you get in there.
That gives the much better option of having the bodies in your hand and the perfect situation to do the physical balance.
A chance also to check hoses, a split is always possible.
You might like to try this as a cross check when you do. Look through the bodies with strong light behind.
Of course, in Australia we use the sun but you may have to use a light,
With the butterflies just slightly open you get a spot on idea of equalness between them.
Yes, the idle screw is in for faster. Its a fine thread so that 1/2 turn aint much in/out movement.
And yes, the s3 means the possibility of 02 sensor problem is gone.
In the meanwhile could you take the slack out of the throttle cable to stop it stalling?
This just occured to me also. You have a  stage 3 so you have a breather filter on top of the hose that draws the air into the ISC, its not blocked or anything?. Limiting that will affect idle, remember Otto saying that squeezing this tube would make a slow idle ( for those that wanted it.) It does.

Hi Tim, hey, good news indeed, enjoy the riding

Keep us posted Carl...!

  I still intend making a sonic clean of the injectors this winter despite having cured the issue. Tanks off for a repaint this year. There's always crud inside it seems, and despite fuel line filters, it's a job Ive been promising myself to do for too long ! 
  Whilst on the subject- does anybody happen to have a paint code for Yamaha's SP white...?

  cheers

TimR

I'm old school from a time with carbs etc and the only electronics where to replace the points. I work with electronically controlled production machinery. My experience with electronic monitoring is that 8 out 10 times there is an underlying mechanical problem.
I'm still interested in the original post and the out come. Although my problem may not be directly related, the low use my MT gets may cause some problems with injectors etc.
To answer your question omeo-mt01, I picked the MT up just over 3 years ago, as a divorce present to myself, and just before the values started to climb. I am a bit over protective of the bike, it is liveried in the Yamaha yellow team colours. It only comes out of dry days so the mileage is low.