TB balance/sync

Read a post in the 12000 km service that talked about doing the TB's and letting the dealer/mechanic do it. Considering some of the other post in that thread related to costs etc I thought I'd post this up for those interested how to do it. (did a search and couldn't find anything similar - hope I haven't doubled up)
This is on a GSX650F so if you have a S model or neked bandit you can disregard any reference to fairings. The gauges are different also, but the info regarding the readout/display is the same

Disclaimer:
Before I start I have to say that I have taken all care to create this how to but I will not take any responsibility if you decide to use this info to do it yourself and cock it up causing the bike to have to visit a shop for repairs.
If you are not confident - DON'T DO IT

Righto.

First thing to do is to check that the TPS is adjusted correctly.
1. Create a lot of slack in the throttle cable. Your user manual will show you how to do this adjustment
2. Remove the RH side cover and find the dealer plug.


3. Remove the protective cap form the dealer plug and put the bike into dealer mode. I use a split pin (you'll notice I have covered the end of it to reduce the chance of shorts) but you can buy a dealer switch from Suzuki at a price around $30 AUD. NOTE: If the pic below dos not make sence for the pin location please say so and I'll explain it better.


4. Turn on the ignition and the dash should show something like this


You'll notice mine shows a _C00. This indicates my TPS needs adjusting. The following is a 'at home' way to do it but to get it spot on you'll either need to take it to a Suzuki dealer and ask them to do it for you or buy SDS
5. Remove the LH fairing and find the TPS


6. Loosen the TPS (DO NOT remove it from the bike). you'll need a TORX fitting T20H (it's the one with the hole in the middle) and it can be rotated to adjust the reading on the dash. It is a finiky, fiddly prick of a job to get right but in the end you need the dash readout to look like this when you have finished and have tightened the TPS (not to tight only by hand. I use a screwdriver type tool).


Now onto the TB balance.

NOTE: Leave the bike in dealer mode. If you have started here and not done the TPS check/adjust, put the bike into dealer mode as per step 2-3 above.
1. Remove the tank (you user manual should show you how). to expose the inner workings


2. Locate the IAP sensor


You need to unplug this and remove it with the hoses that are attached to it. This is what you are removing


You can just unplug the IAP sensor and disconnect all the hoses from the engine (those small barbs on the engine will become the test points for the balance tool) but I've said to remove it all so it is easier to see what you are doing, that's all
3. Hook up your balancing tool. I use a Morgan carbtune as I find it the easiest to use and there is no maintenance that goes with it. It is up to you what you use tho.
Locate the adjusting screws for each TB. Here is a pic of cylinder 2


and cylinder 3


Use a torch and take your time, you will find them.
4. Make some kind of thing up to hold your tank above the bike so you can access the adjusters while the bike is running. Here is what mine looks like all ready to go. Nothing pretty, but it works and is safe and secure.


5. Hook up the tank and start the bike. You will a code in the dash that is -C013. This is the code for the IAP you disconnected in step 2 and is perfectly normal. You now need to wait until the bike cooling fan kicks in. This ensures your bike is warmed up enough to do the adjustments. I also use a small fan to blow air onto the radiator and help move exhaust fumes out of my shed. I recommend you do this also as it will get quite hot in there.
This is what mine looked like at first start up


and after it was warm


So you can see I needed to do mine.
6. Adjust each adjusting screw (cylinder) to end up looking similar to this. (Mines not spot on as I still need to run the bike in and I'll be doing it again after the first service. It is better than before tho)


A few tips while adjusting.
*Do not make any changes to the adjustment while the fan is running, wait for it to stop.
*Make small adjustments slowly to be more precise.
*Turning the screw in (tightening it) makes the meter rise (increase in vacuum)
*Turning the screw out (loosening it) makes the meter fall (decrease in vacuum)
*Don't turn the screws out (loosen) too far as they will come out
*If you think you have it where you want it, crack the throttle and release it,wait for the engine to stabilize and check the gauge again. This is very important when you are almost finished and happy with the results.
7. Once happy remove the gauges and put your bike back together.

If there is anything you would like clarified please ask and I'll try to explain with a little more detail.

chears

that's obviously a good thing to do - i couldn't do it in a fit though!!

Good post dhula!

So at 25000km I finally got around to balancing the throttle bodies using the Carbtune. Turns out cylinder 1, 2 and 4 were close to equal on the gauge but number three was quite a way out. It's really not that hard if you are at least a little mechanically minded (I'm not) and follow these instructions provided by dhula.

Going by the workshop manual, you need to have the bike at operating temperature (85-100°C) to do the balancing. I had the Bandit hooked up to the Suzuki Diagnostics software and can say that the fan comes on at 105°C, so if you wait for the fan to go off that is when you should adjust it.

Updated to include TPS adjustment/setting info

Good work Dhula. If there was a rep button I'd hit it for you. I need to do this on my bike, it's starting to be a bit of a bitch at low rpm which I'd suggest is the TB balance and possibly the TPS slightly out.

Looks like I have another tool I need to purchase

Be cautious if you are going to adjust the TPS reddog as the PC3 reads from it.
I'm certainly not expert with PC gear but I presume if you adjust the TPS on your bike it will have an effect of the what the PC3 does and this could effect how the bike runs and performs.
I recon it will be as easy as resetting the PC3 to the new TPS setting but give your tuner a call to make sure.

Worst case scenario is I disconnect the PC3 mate... I'll speak to Todd at Bunbury Ducati, but it went on early in it's life, so the TPS should be spot on

dhula wrote:Be cautious if you are going to adjust the TPS reddog as the PC3 reads from it.
I'm certainly not expert with PC gear but I presume if you adjust the TPS on your bike it will have an effect of the what the PC3 does and this could effect how the bike runs and performs.
I recon it will be as easy as resetting the PC3 to the new TPS setting but give your tuner a call to make sure.

After the bike is warmed up, plug in the PC to your computer, in the software you can calibrate your TPS. Easy as.
BTW good write up thanks

I adjusted my TPS, which always showed _C00 using the manual method of loosening it and doing it by hand until I achieved -C00. It worked a treat. My bike went in today to have the rectifier replaced as part of the recall, so I asked the dealers to put it on the SDS and clear any old fault codes and check the TPS setting. They advised that it was spot on, so obviously this all worked.

My bike is still jerky on the overrun at low speeds, snatching at the chain and making me pull the clutch early as it really jerks about. Balancing the TBs helped a bit, and it's annoying as it idles really well, and screams to redline. No surging at a constant speed, but the 2000 rpm slowdowns are a bitch.

The bike is Stage 1 Dale Walker, but it does the jerky bit whether bog standard or modified. New plugs, everything to spec, so I think the next job is to pull the secondaries and try that out.

A nice clear set of instructions dhula,

Good job

Smitty

Great info thanks more work i can do myself

Syncing my TBs as per these instructions on the weekend has made for markedly smoother running. It idles more smoothly and even changes gears more smoothly as the engine spools up and down faster. I synced mine off no. 2, and all were equal at 30 on my CarbTune, which is much higher than in the pics above. Very happy with the result, as the TPS is spot on, the TBs are synced and she's all good!

Kewwig

That'll be that cold kiwi air pouring through it that sweetens it up

The pic of the carbtune is on a GSX650F not a 1250 bandit so is a bit different to what you will see.

Unlike a lot of bike makers, Suzuki doesn't give a spec for the vacuum reading and just says make them equal. I have tried many different readings to see what is what in the hope of suggesting one but haven't got there yet. I'm messing with slightly out there readings at the moment to see what happens with the hope of more info into the brain bank soon(er or later)

jaba01 wrote:Kewwig

That'll be that cold kiwi air pouring through it that sweetens it up

Her Indoors keeps muttering about methane. I can't understand it!

dhula wrote:The pic of the carbtune is on a GSX650F not a 1250 bandit so is a bit different to what you will see.

Unlike a lot of bike makers, Suzuki doesn't give a spec for the vacuum reading and just says make them equal. I have tried many different readings to see what is what in the hope of suggesting one but haven't got there yet. I'm messing with slightly out there readings at the moment to see what happens with the hope of more info into the brain bank soon(er or later)

D'oh! Of course. The larger cylinder volume would explain the higher vacuum. I guess twice the cc would result in a similar pressure differential as an engine's just a pump and each cylinder should be proportionally more "sucky" (now there's a technical term....). I have really noticed the improvement in rideability. The bucking on the overrun is gone and the gear changes are far less clunky.

I trawled for the Suzuki mm Hg readings, but as you say, there's nothing in the service data about the vacuum level, only the comparison between cylinders. It's certainly been an interesting exercise. I think I am in the wrong job as I enjoy this sort of stuff.

I am seriously thinking about getting myself a Healtech OBDII reader now!

Just want to thank the author of this how-to. I followed your instructions and found the procedure straight forward.
Observations
1 When the bike is first started from cold the idle is at a steady 1000rpm.
2 When partly warm there is a pronounced increase in rpm to 1500rpm which stays constant throughout the test procedure. A function of the computer delear mode?
3 If the throttle is held above the idle revs you can identify cylinders with a higher vacuum

Allowing for differences in cylinder efficiency, valve clearances etc is this an indication of relatively strong v weak cylinders?

Discussion: Would extreme differences indicate possible problems with an individual cylinder?

I'd expect so or a major air leak on the intake side

If you have balanced them all recently then you would probably feel/hear the difference that would point you to the fact something was amiss with the engine.
A huge difference between cylinders could point to a big problem, but what the problem is can be a bit of a mystery to some as vacuum and what it is doing can point to many problems.
From as simple as incorrect ignition timing to a burnt or stuck open valve.

Click here for a guide that shows the most common readings and what they usually indicate.

Problem that is with bikes and the carbtune is that it is really hard to see what it is showing and even when you use a dial gauge per cylinder the readings can be a little misleading due to only reading what is happening on one cylinder

I would be wary about "adjusting" the TPS.The manual states this assembly should not be removed.The reason for that is the intake air pressure sensor is part of the same assembly and loosening the screws and disturbing the position of the assembly risks introducing a leak in the gasket that seals the IAP.This would put the IAP out of calibration.The manual also says that the sensor is not available as a part - if it fails you get to buy a whole new throttle body assembly.The TPS/IAP/IAT assembly is not designed to move on it's mounts for adjustment.

The TPS can be adjusted by the throttle stop screw between 2 and 3 throttle bodies - difficult to do though.

If you are talking about the adjusting screw between 2 and 3 that you can see from the top of the engines then this is for "balancing" 1-2 and 3-4.ie, for getting all 4 tb's to open at the same time at the same rate. If you read the manual it says not to mess with this one also.

If you are talking bout the adjusting screw that has a locknut on the underneath of the tb's (instructions for how to do this adjustment are around the place on the interweb) then by adjusting this one you are setting the throttle shaft (and thereby the throttle plates) to the sensor not the sensor to the throttle shaft. The manual says not to mess with this one also.

The reason I haven't talked about the 1st one is that it should be fine straight out of the box and there is no need to mess with it. Only if you split the TB's (not recommended unless you know your shit and you probably won't get the parts from a dealer anyways) will you need to mess with this one.

The reason I haven't talked about the 2nd one is that IMHO it is the incorrect way to do it. There are those that will disagree with me and that is fine (Have had a few strong discussions via PM on this one) but if you want to try it then please do so with care as it may bring with it other small issues that may need extra reworking to get the bike to work close to what it's sposed to

I don't believe there is anything to be gained by manually adjusting the TP sensor,the amount of displacement to move from _COO to -COO was negligible on my bike and did not even result in a change in idle speed with the bike in dealer mode.
The manual also says don't touch the AIP/TPS/AIT sensor,just as you correctly point out,it says don't touch the set screws.

If you don't believe there is anything to be gained by adjusting the TPS to where it should be, don't do it, but I'll offer what I know for info/consideration

While it may not take a lot of movement at the TPS to move from _C### to -C### if you have access to the healtech OBD tool or SDS you will see that there is a difference in the reading and what the ECU sees because of it.

It won't change idle speed substantially if at all and that is not the reason for the adjustment. The reason for the adjustment is to get the ECU seeing what it is supposed to see and what engineers that are way smarter than me have programmed the ECU to make optimal use of.

Yes the bike will run with the TPS set to where ever you want, but the engine is not running best it can in these cases



If you want to change idle speed you can do a number of things (including but not limited to):
1. Use either of the screws mentioned above but this brings with it other considerations/issues and I don't recommended unless you know your shitz
2. get into the maps in the ECU will appropriate software/hardware and change it.
3. mess with the TB sync readings (vacuum) to get a higher/lower idle speed. The ISC will eventually compensate for this given enough time

I'm just wondering if you put a lot of slack in the throttle cable to do the synch I assume you take the slack back to normal when you finish the synch - then won't taking the slack back out upset the balance ?

Not trying to be smart - just trying to fully understand the process.