TPS/STV/FI...adjusting issues, possible HOWTO in the future

[Riotstarterr]

Hello everyone, I need some help from you, hopefully there'll be someone among you who will know better than the people I asked so far (motomechanics and people on other forums, etc.).
I apologise if it's gonna be longer reading, but I'm not really good at writing it short, but I will do my best.

The bike is SV650S K3 (2003)

My TARGET is pretty simple, I want my bike to be at 100% working condition with no issues or even quirks.
My biggest gripe is the infamous jerkiness/twitchiness AND Fast Idle not working properly. Now, I did some standard, well-known steps to improve it, first thing was proper TB synchronization, TPS adjustment and whole new chain set with sprockets. All this helped to some extent, but it's just 50% of the way where it should be.
Regarding the Fast Idle, it was not working at all, meaning when I started the bike when it was dead cold, RPM were always at hot idle (1300+-) and struggled to keep running with some hiccups for a few seconds. I tried to adjust the Fast Idle screw and it helped, RPM were at 2100 for next two starts, but now it does not work again for some reason. While I was adjusting FI and TPS, I noticed that Secondary Throttle Valves (STV) seems to be out of sync (different height/angle and it never got fully open).

That's where I got lost. My final goal is to have:
Throttle Bodies (TB) synced
STV (Secondary Throttle Valves) synced and properly adjusted
Throttle Position Sensor (TPS) properly adjusted
Secondary Throttle Position Sensor(STPS) properly adjusted
Fast Idle (FI) properly adjusted and working

At this time, it's only TB and TPS adjusted, the rest is not working (FI) or is terribly misadjusted (STV).

Now, I want all the above working at the same time obviously, I've read through many manuals and forum advices, but it didn't get me very far, some are not really clear, some are for different bikes (SV1000), some are counterfeiting with the others and therefore not trustworthy.
What I'd need is complex and thorough instructions, how to do all the above and what to do first and what to do next, so the rest won't get out of sync/misadjusted again in the process, as some mechanics told me it will if I don't do it properly.

I know I ask for a lot of work, but I was thinking, if we got heads together and I would be able to follow instructions and do it, I could take pictures and make a proper step-by-step sticky thread, that I'm sure would help many SV riders here and it would be on at least the same level of helpfulness as the TPS thread is for most of us, not to mention it would improve the quality of our SVlife http://www.svrider.com/forum/images/smilies/smiley.gif

Huge THANK YOU to everyone who will contribute to this in any way.

[Bibio]

you will never fully get rid of jerkyness on a v-twin, i'm afraid its the name of the game. learn proper throttle control instead. a v-twin requires a lot of clutch control/slipping at low speed manoeuvrers to keep the revs high. once you master low speed manoeuvrer control then you will master the jerkyness.

DO NOT MESS WITH THE STPS. this is controlled via the CDI to correct the air flow. getting this wrong can mess with the fuel mixture. only and only adjust the STPS if you have the correct tools (SDS, DMM) and you know what you are doing.

the first thing to be done is a full service including the spark plugs and air filter. once this has been done then set the idle speed to around 1300rpm at fully warmed up.

Throttle Body sync. you must adjust the idle speed as you adjust the sync. adjust the sync then let settle then adjust the idle speed and repeat till its done. dont go mad looking for perfection as you will never achieve it. in the grand scheme of things its not that important and as long as its 'near enough'.

NOTE: on twin spark bikes K7> you must use an SDS tool, no iffs no butts as you need to lock the air idle valve down. the K7> twin spark is also set via the bypass screws and NOT the usual butterfly adjustment screw.

last thing to be done is the TPS. do not use a DMM for setting the TPS. you need to do this via the dealer mode line markings on the instrument cluster. the TPS is exactly what it says a Throttle Position Sensor. to set this for least jerkyness you need to set it so the line moves the moment the throttle is turned (excluding slack in the cables). setting the TPS in the manner i have suggested severely reduces engine braking but doing so smooths most of the low speed jerkiness.

[Bibio]

something i forgot to mention is partial/blocked injector mantles. its not common but it does happen. IIR muzikill on this forum had the problem and like you tried everything until he got the injectors serviced which cured the problem instantly.

BTW. motorcycles need maintenance, things go wrong, you can never make a one time adjustment, its all continual servicing. yes some adjustments or servicing items need not be done for a long time but they will need done.

the biggest investment you can make for any motorcycle is tools and the knowledge to be able to use them. there are some specialist tools that you may only use every 30k miles so if not willing to invest in them then take your bike to someone who does have them when the time comes.

[Riotstarterr]

Thanks for the reply.

I know some jerkiness is normal with this engine, but what I'm experiencing is definitely not normal.
Just FYI: valves are OK, TBs are synced, TPS is adjusted.
Only thing I noticed, as I said in the original post, is that Fast Idle is not working at all and Secondary throttle valves seems to be out of sync (every valve is opening differently and the opening itself seems weird too).

That is why I want to have secondary valves synchronized so it opens the same at the same angle and STV sensor adjusted too, so it opens the valves properly. Of course, working Fast Idle would be great.

Btw, not sure what you mean by STPS, but TPS is adjusted and CAN be adjusted pretty easily, same goes for STV sensor (STVS), according to manual.

[Bibio]

my mistake, i meant the STP. with regards to the STV's (secondary throttle valves, top butterflies) yes they do flutter under normal running.

essentially there are 3 sensors on the TB's. the TPS (throttle position sensor), STP (secondary throttle position) and the STVA (secondary throttle valve actuator).

the TPS is the main sensor that senses the position of your throttle.
the STP is to control the air intake and is auto controlled via the CDI (do not touch this as its factory set and requires careful setting up).
the STVA is essentially a choke but automatic and again is controlled by the CDI but is also linked to the temp sensor. only adjust this if you know the temp sensor is working correctly.

problems associated with the STVA are usually the fault of a duff temp sensor. if the temp sensor locks closed then the bike will not idle properly cold as its not sending the correct temp reading to the CDI to tell it to activate the STVA. visa versa to above when hot.

[Riotstarterr]

Alright, that shines a little bit more on the issue.
However, it's still not fully clear.

STP = is it that sensor for secondary throttle valves? Service manual says you CAN adjust it, says nothing about being CDI controlled. Page 244, STP sensor adjustment.
This also says you can adjust it: http://www.sv-portal.com/forums/5-tweaking-tuning-tricking/14181-secondary-throttle-valve-adjustment.html
However, it does not say anything about "syncing" the butterflies (secondary plates).

The info about temp sensor is good, however I'm not sure which temp sensor you mean - the one that senses cooling liquid temperature and is also shown on the dashboard display? I think that one works okay, because the temp is shown correctly, also the ventilators are turned on when it reaches approx. 102 Celsius.
Just FYI, one mechanic exchanged one temperature sensor that was faulty two weeks ago, because the ventilator never turned on, after the switch, it's working fine.
Just so you know, I don't know how many temperature sensors are there, so I'm trying to tell you what works and what I see, if that's what you were talking about.

Last thing, nobody yet commented on the out of whack secondary throttle valves (the plates itselves) and the fact it does open fully and that every plate is in different position (ie one plate is horizontal, where as the second is half open). Can you shed some light on this, if you know anything about it?

[Bibio]

lets get one thing straight. the workshop manual is just that, its a manual intended as a reference for technicians who suzuki assume know what they are doing therefore they omit a lot of warnings. just because the manual states that you can adjust something does not necessarily mean that you should without diagnosing the problem first.

as far as i'm aware there are two temp sensors, one on the radiator to engage the cooling fan and the other is on the thermostat housing. its the one on the thermostat housing that goes dud.

[Riotstarterr]

And which sensor reports the temperature on the display? If I'm correct it's the one in thermostat.
If yes, it should be working fine, considering it shows the temperature correctly.

[Bibio]

And which sensor reports the temperature on the display? If I'm correct it's the one in thermostat.
If yes, it should be working fine, considering it shows the temperature correctly.

thats an assumption. i have just checked the workshop manual and i was wrong about it being a simple switch. the sensor can read different values at different temperatures. if these values are wrong the it sends different data to the CDI. you will still get a temp reading on the display.

[Riotstarterr]

Ok, I will think about replacing it.

Anyway, I'm gonna remove the STV plates completely, without removing anything else. Then I will install Gipro ATRE on monday and I'll see how it goes.

[Bibio]

Last thing, nobody yet commented on the out of whack secondary throttle valves (the plates itselves) and the fact it does open fully and that every plate is in different position (ie one plate is horizontal, where as the second is half open). Can you shed some light on this, if you know anything about it?

i can only take a few guesses at this on. first one would be that instead of adjusting the correct screw when doing a TB balance the STP link rod screw has been adjusted instead. another is that the STP sensor is jammed. another is that the STVA is jammed.

are both (top) plates full closed when cold?
do the (top) plates go through the correct fully open/close sequence when the ignition is turned on?

NOTE: the buzz buzz you hear when turning the ignition on is not your fuel pump priming as a lot of people think but instead its the STP valve plates doing a dance, you cant hear the fuel pump priming unless you stick your ear on the tank.

[Bibio]

Ok, I will think about replacing it.

Anyway, I'm gonna remove the STV plates completely, without removing anything else. Then I will install Gipro ATRE on monday and I'll see how it goes.

my advice is DONT. you will see no gain, its a placebo effect. plus its also part of the cold running circuit.

[Riotstarterr]

They are closed, but not 100% (one si more closed than the other). I actually know about the whiney noise when ignition is on, as I noticed that the last time I was checking the STV and Fast Idle.

Do you have any objection against the STV removal?

[Riotstarterr]

Alright. I'm just reading through this (link below) and basically everyone that has done it says it's a great mod with basically no negatives, not to mention they say Fast Idle works normally even with STV removed.

http://www.svrider.com/forum/showthread.php?t=261977&page=15

[Bibio]

ask yourself. why did suzuki put them in if they never needed to?

as i said its a placebo effect but your welcome do do what you like as its your bike.

[Riotstarterr]

Well, I'm thinking like this: my STVs are misadjusted and there's chance that some other stuff is out of sync too (STP,...). If I remove that, I will remove the troublemakers from the equation, therefore it cannot hurt anything.
You could say I should just get it right, synced (STV, STP) and/or exchanged (STVA, temp sensor) but that takes time, a lot of money (in case of exchanging stuff) and someone to do it (I didn't find such a person and don't really want to do it myself with having not enough information, as stated originally in this thread).
And removing these plates should help in my case, at least that's what I'm thinking.

Feel free to correct me if I'm wrong as I'm here to listen to opinions and more experienced people.

[Bibio]

if there is a problem there is a problem and resorting to a bodge will not rectify the problem. doing supposed performance mods only works if the bike is running correctly in the first place.

in most cases its just doing the correct sequence of adjustments and understanding what NEEDS done and how to do it. blindlessly trying things can make matters worse. identify, diagnose and rectify.

lets get real here, the SV only pushes out around 70bhp at most so the best you hope to gain in reality is up to 10bhp with the 10bhp costing MEGA cash to gain.

no matter what shiny glossy mags tell you or people selling their wares on forums they are all trying to make money with fancy marketing and bull speeches.

yes i sometimes sell wares on this forum but i would like to think that mine do actually make a difference and none of them are performance related. i can make TRE mods with my eyes closed but i refuse to do so as its bull. let me put it this way, i placed a thread over on SVrider about selling my swingarm marker plates and got almost no response (i think it was two).. why, well simple, it was not a performance item/mod and i never tried to mystify people will bull. over here though i have sold hundred's of them with absolutely no complaints, in fact nothing but praise.

[Riotstarterr]

I don't think we are on the same boat;
The last thing I'm looking for is any hp increase. I'm in for smoothing things out, for better behaviour of the bike, not performance. That's what this was all about since the beginning.

[Bibio]

then you are on the right track but you need to rectify your problem and not resort to bodging something like others have done as they dont understand how to fix the problem either.

the section on adjusting the TB's in the workshop manual is there for stripping down and assembly procedure. you must identify the problem first, then move onto diagnosing the problem to find the troublesome component, then you replace or adjust the component to rectify the problem.

apart from basic maintenance like TB's sync or TPS adjustment you should not need to touch any other part of the TB's unless you have identified a component as being defective or needing adjusted.

[Riotstarterr]

Well, I've removed the plates just now and adjusted Fast Idle once more. FI is working now (so far), so we will see.
Motorcycle seems to be running OK, but I didn't have the chance to run it properly, just around the garage and into the parking spot. But I've noticed less engine braking and smoother operation even now, tomorrow will be a test ride, that will tell more.

I've managed to strip two of the four screws, they are so muddy and stripped right away, so I had to drill them. The leftover screw body without the head stayed glued in the bar and I didn't manage to get it out, it's so sticky, so I hope it won't get loose and drop into the engine. I should remove the whole throttle body soon and drill it properly so there's only hole left.

[Dave-the-rave]

My curvy is a vtwin and isn't jerky. Not unless I forget it has a high compression engine. :D

[Riotstarterr]

Today I took the bike apart again, and removed the rest of the screws that were there. Now both screw holes are drilled through and STV plates are gone. While I was at it, I cleaned the throttle body a bit.
I have to say, I don't notice much of a difference with the STV plates removed. It's still jerky and engine is braking hard. I also notice that the bike is unable to hold stable RPM, meaning when I hold the throttle, it fluctuates noticeably. In example, I try to hold stable 3000RPM, but it's not possible to keep it at it, it's fluctuating +-150rpm, therefore it's behaving jerky while trying to keep stable speed. I suspect faulty/worn TPS.
Also when I had the TB's removed completely, I looked down the intakes and it's pretty dirty down there, the black greasy crap everywhere. I would not expect that from a bike with 32000km.

[sl0th86]

Does it really make that much of a difference? Just tried mine and was reallllllly carefull but only managed to get 3 off and the last one just rounded straight off first go with no effort!!! I was gutted, wanted to see if it'll make a difference lol


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[Riotstarterr]

On mine, not really I'd say. And I had to drill two screws through, as they stripped so easily.

[sl0th86]

Yeah so all that effort for not much of a difference? I did the other 3 back up and left it for now. If it made a hugeee improvement i mite of made the effort to get that last one out hmmmm


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[Riotstarterr]

Well, I'm not saying there is NO difference, just that I didn't notice much. But personally, I prefer smoothness over power and that was not delivered in my case.

Only thing I may have noticed is, there is some noticeable power kick at higher RPMs that was not there as far as I remember.

YMMV, other people said they noticed a lot of improvement. On the other hand, I can't say I'd noticed any shortcomings either, so it won't hurt if you remove it, it can only get better.

[Bibio]

you have rounded the screws as you didn't know that they are thread-locked in and that the screws are JIS type. you need a soldering iron to heat the screws to soften the thread-lock and a proper JIS screwdriver to remove the screws.

my advice is to get yourself a second hand set of throttle bodies.

its not just the TB's that can cause lumpy running it can also be caused by a faulty rec/reg, low oil, bad spark plugs and lots of other things.

i'll butt out now and let you get on with it but my last words are, the suzuki techs put the STV in for a reason.

[Riotstarterr]

I knew about the thread lock, not about JIS though. Does not matter now, holes are drilled and screws are gone, I don't see a reason to buy another TB yet.

And twitchy behavior because of faulty regulator? Never heard of it.


P.S. The reasons are fairly well-known, among others, it's less noise produced and emission thing at some RPM ranges. Not every reason is worth, or good at all. Think about the retarded timing on Suzuki's, for example. Or max speed limiters, etc. You can't argue like that.

[Seeker]

What's the purpose of the secondary throttle valve?

When the primary throttle valve is opened it initially causes the vacuum through the throttle body to collapse depending on engine speed and the amount the valve is opened. Using a secondary throttle valve to modulate the airflow smooths out the vacuum transitions and gives a smoother ride. The bigger the pistons the more pronounced the effect will be, so a 1000 cc V twin benefits more with a secondary throttle valve system than a 650 cc V twin, but a high revving 4 cylinder bike will also see advantages to having such a system.

[Bibio]

I don't see a reason to buy another TB yet.

And twitchy behavior because of faulty regulator? Never heard of it.

P.S. The reasons are fairly well-known, among others, it's less noise produced and emission thing at some RPM ranges. Not every reason is worth, or good at all. Think about the retarded timing on Suzuki's, for example. Or max speed limiters, etc. You can't argue like that.

i'm going to be blunt but hey its a forum, who cares and this will be the last time i answer anything in this thread.

coz you have feked the ones you have by not understanding how to solve the problem you have.

well its part of the ignition/charging system so if its faulty then will cause running issues, i'm not saying it is the rec/reg but have you checked it?

yes i can read lots of things on the internet to but let me assure you that all motorcycle manufacturers are doing the exact same thing, if they never you would not have new motorcycles. this does not mean that they are wrong or indeed need to be removed.

... you say that the revs are fluctuating.. why would that be?

i'm not trying to be negative, far from it. i am actually trying to help.

What's the purpose of the secondary throttle valve?

When the primary throttle valve is opened it initially causes the vacuum through the throttle body to collapse depending on engine speed and the amount the valve is opened. Using a secondary throttle valve to modulate the airflow smooths out the vacuum transitions and gives a smoother ride. The bigger the pistons the more pronounced the effect will be, so a 1000 cc V twin benefits more with a secondary throttle valve system than a 650 cc V twin, but a high revving 4 cylinder bike will also see advantages to having such a system.

i was hoping that the OP might just go and find that out for themselves but the rabbit is out the hat now.

[Riotstarterr]

Well, I will check my regulator ASAP, that's for sure, because it's fairly easy operation and cannot hurt anything to be sure.

However, to be 100% clear, I had issues before doing the STV removal and after removing it, it's the same, no issue disappeared and no issue appeared. So in my case, it didn't help, it didn't hurt anything, at least not anything that I would recognize.
The topic with STV removal is full of people who says they have good experience with STVs removed, who am I to tell them they are all wrong. I just wanted to make my own opinion and it's neutral at this point.

[Seeker]

Could it be that the reason you have not seen any issues appearing/disappearing with the removal of the STV is that yours was not functioning correctly?

I know people have removed the STV system but here are some that have refitted it (for smoothness) although it's on the DL1000

http://www.stromtrooper.com/maintenance-tech-products/59713-do-not-remove-your-secondary-throttle-plates.html

So, each to their own...good luck, anyway.

[Riotstarterr]

I think I'm **** outta luck.
This sunday, I took the bike apart again and did all the processes again, including voltage measurements of TPS, STPS, etc.
TB synced, TPS adjusted, STP adjusted, Fast Idle adjusted (precisely according to manual), intake cleaned. Every sensor was checked for consistent behaviour with multimeter. Actually the STV valves (well, the rest of it) seems to be working OK too even though the plates are removed at this moment.
Note that my valves are checked and OK, there is new rear chain and sprockets installed, Gipro ATRE installed, new air filter.

There's nothing I came across that would point out to any issue, yet there are issues;
Bike is still jerky a lot with rapid twitching back and forth when I try to hold speed constant (most noticeable at lower speeds). I have noticed, that when I have bike parked and started - in neutral and try to hold RPMs constant at some value (let's say 3000rpm), it's not stable and fluctuates +-200RPM, which is what probably causes the rapid twitching. I had voltmeter connected to TPS at the same time and checked, that the values of TPS were constant and not moving while holding the throttle, yet the RPMs were fluctuating.
Oh and the damn Fast idle does not work even after adjusting, it just does not do anything.
All of the mentioned issues were there even before I did all the stuff above (ATRE, adjustments, exchanges, etc.), nothing has changed.

Issues are the same even when the airbox is completely removed and the bike is started.

All this leads me to a thought, that there's an issue with the engine itself or something wrong with fuel injection, maybe even ECU issues.

[Seeker]

Could it be a vacuum leak, they often cause surging/poor idle?

There's a guy on the US site with idle problems, maybe his thread will have some suggestions?

http://www.svrider.com/forum/showthread.php?t=135367

(sorry about linking to another forum)

[Riotstarterr]

Idle is fine, that's the thing, it's the RPM above idle when the throttle is applied and held constantly at one position, where the fluctuating appears.. And I have checked for vacuum leaks, there is none.

[Seeker]

I don't know how you checked for vac leaks - but one way is to spray WD40 over the suspected area with engine running and see if the idle changes.

Here's a left field kind of question: is your clutch switch connected and functioning correctly?

Other than that, dirty fuel injectors? Try some seafoam?

Maybe a compression test (and a leakdown test) to check the health of the engine.

[Seeker]

How long has the TRE been installed?

[Riotstarterr]

Checked with carb cleaner.

Not sure about clutch switch, but I guess it's working since I cannot start the bike without pulling the clutch in.

Seafoam is not available around here where I live. Ordering via eBay costs a fortune to get it here.

Compression test...mhmhm...will think about it.

EDIT: TRE is there for about a week. Didn't notice any change after installing it. I mean no positive, nor negative change.