Engine runs like a champ when cold, but started to shuddered when warmed up.

[abong]

First of all, my ride is a 2013 Matt Grey US Spec which i bought with 2,700k kms on it.. And now running at 14k kms already.. I'm running on a RON95 unleaded petrol..

Last month, i've sent my bike to a workshop to change the colour scheme from grey to silver.. so in the process, the petrol tank and the all of the cowling was disassembled..

After the repainting was completed, i went for a trip which is around 1,800kms with no problem at all.. the next day, as i was ready to go for a evening ride i started up my S10 and went for a ciggy so that bike get properly warmed up.. as i engaged to first gear, the engine died.. i restart it and put a little throttle and then I've realized that the engine become sort-of shuddered.. shuddered may not be the exact word to describe the situation, but the situation was like a carburetor type engine which does not have enough air to feed the carburetor.. that srotttt.. srotttt... air sucking sound..

here i attached the youtube link to show the conditions :
https://youtu.be/d9HRTQ3Edpg

When the video was recorded, ive open the throttle fully and it can even pass 2k rpm..

i was disappointed that evening so i let the bike as it is and planned to have a look at it the next day.. so the next day, i started my bike and to my surprise the engine works like charm! it was revving freely to the red line.. i was so happy and decided to take it for a spin and after a 1 minute slow ride and the bike are properly warmed up, the bike started to shuddered again..

so i took my bike to my service guy and ask him to look over my bike.. what he did :

1) open up the spark plug, the most left spark plug which sits beside the radiator corroded, so i decided to change a new set.. tested the bike, after properly warmed up, it happened again..

2) clean the fuel injector :- same..

3) measure the primary & secondary resistance of the plug coil :- everything is according to the manual

4) open up the head to check whether it is a valve shim issue :- nope, clearance is all up to spec..

There is no Engine Light warning came up, and there is no Error Code history.. my bike doesn't have that canister under the tank, just two straight breather hose goes down..

i hope my fellow friends here can help me and point me to directions i can look over..

 

[WJBertrand]

What happens if you open the gas cap when it’s running like that? Thinking a vent hose might have gotten kinked when the tank was replaced.


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[abong]

What happens if you open the gas cap when it’s running like that? Thinking a vent hose might have gotten kinked when the tank was replaced.


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No sound of vaccum-a-like sound heard when opening the gas cap..

 

[2daMax]

Maybe similar issues. http://www.yamahasupertenere.com/index.php?topic=10404.0

Causes could be:

1. Bad wiring especially the Stator coil wire. More the wire around during idling and see if it changes things.
2. Bad TPS sensor or connection. The Throttle position actuator is on the RHS Throttle body.
3. Sticky throttle grip where you need to remove the grip and lube it.

If it runs fine during cold, and bad during warmed up, it points to the closed loop control. Big suspect is the Throttle control, it not being opening up to let air enter or the ECU is reading bad signals and having a hard time trying to cope (surging rpm).

Check for vacuum leaks at the Right side TB rubber cap.

Also check if your Stator is producing 14V.

 

[abong]

Maybe similar issues. http://www.yamahasupertenere.com/index.php?topic=10404.0

Causes could be:

1. Bad wiring especially the Stator coil wire. More the wire around during idling and see if it changes things.
2. Bad TPS sensor or connection. The Throttle position actuator is on the RHS Throttle body.
3. Sticky throttle grip where you need to remove the grip and lube it.

If it runs fine during cold, and bad during warmed up, it points to the closed loop control. Big suspect is the Throttle control, it not being opening up to let air enter or the ECU is reading bad signals and having a hard time trying to cope (surging rpm).

Check for vacuum leaks at the Right side TB rubber cap.

Also check if your Stator is producing 14V.

Is that you Leslie? Good to find you here..

1) Will try to move it around.. if that's the culprit, i guess i have to re-route the stator coil wire..

2) By that you mean to clean up the connections/ contacts by using contact cleaner?

3) i dont think this is the case since I've never had any down-revving problem, only up-revving problem..

I'll let the service to have a look at these matters..


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[2daMax]

Hi abong,

Yes, that is me.

For #2, check the contacts, connectors, for entire length of the wiring. Yes, clean them too on the interconnects.

For #3, Boy Harimau had this sticky throttle issue once, and probably worth lubing it as a maintenance thing. Agree, it is unlikely to be the cause.

I may be wrong, but from what I gather, the wiring induced issues to unstable throttiling seems to affect US spec bikes mostly

 

[Checkswrecks]

Running like that could be water in the gas. I'd start by draining the gas and flushing the tank with some fresh gas. You seem to know how easy it is to remove the tank. In re-installing the pump, just be aware that it is easy to twist or roll the o-ring and create a slight fuel leak that you only find after it is all put back together.

 

[trainman]

although it took a while to appear I would bet on the tank removal being the cause, have it removed again by a good mechanic, stand there to witness and check all hoses, vents, connections, air filter and the throttle cables where they go onto the throttle sender device

the lack of fault codes suggest its a mechanical or fuel/air issue that the ECU wouldn't be able to detect

let us all know the fix!!

 

[abong]

Running like that could be water in the gas. I'd start by draining the gas and flushing the tank with some fresh gas. You seem to know how easy it is to remove the tank. In re-installing the pump, just be aware that it is easy to twist or roll the o-ring and create a slight fuel leak that you only find after it is all put back together.

Did that already on the first place as I thought that the heavy rain that i went through were the cause..

 

[abong]

although it took a while to appear I would bet on the tank removal being the cause, have it removed again by a good mechanic, stand there to witness and check all hoses, vents, connections, air filter and the throttle cables where they go onto the throttle sender device

the lack of fault codes suggest its a mechanical or fuel/air issue that the ECU wouldn't be able to detect

let us all know the fix!!

We'll be doing that later this day.. although i also thinks that it is related to the removal of the tank previously, but I guess it'll be most unlikely caused by kinked hose, blocked vents since it only happens after it has properly warmed up and not before.. anyway, certainly will go on every opinion here.. thanks guys..

 

[2daMax]

Check the air box, if there is resident rat in there. Well, see if there is any blockage. A couple of Singapore S10s who had installed silicone rubber mats to prevent water splashes to the engine at the front of the engine had the mat blocked the inlet opening after a maintenance job.

 

[abong]

Check the air box, if there is resident rat in there. Well, see if there is any blockage. A couple of Singapore S10s who had installed silicone rubber mats to prevent water splashes to the engine at the front of the engine had the mat blocked the inlet opening after a maintenance job.

I've blew any dust collected in the airbox while i was changing the spark plug.. airbox are squeaking clean..

I didn't install the splash mat so far so i guess it's not the issue..

 

[abong]

Update for today.. we drain the tank to put in a new fuel just as precautionary measures to check whether there is any mixtures of waters.. but there is no trace of waters present, and we pour in fresh fuel..

Pull off all the sockets connection and apply contact cleaners and let it air dried..

Start up the bike, and the result still the same..

Then we decide to perform the Jet Clean procedure again just to be on the safe side.. the service guy were using benzyn if I'm not mistaken of what he said.. as a result, we saw some debris in the benzyn.. that's make us decide to clean the fuel tank as well..

My oh my.. RUST!!! A handful of it!!! That's make us wonder, why the rust doesn't came out on the first day during the first time we clean the tank with petrol? It came out loose when in contact with that Jet Clean thingy.. so now going to send the fuel tank to another shop for thorough flushing.. hope this will settle the problem..

 

[Thrasherg]

Are you just getting the tank cleaned, or will you also have it sealed. with that much rust I would be concerned for the future, getting it properly sealed would be your best option (short of buying a new tank). I trust you are going to change any inline fuel filters for the injection system as they might be blocked.

Gary

 

[Nikolajsen]

WOW... this is crazy...so much rust (are you sure it is rust?)
There must have been water in the fuel tank for quit some time, previus to you buying it.

 

[mebgardner]

Time to measure fuel pressure to the TBs.

Also, inspect and replace any gas filters (I think they're in the fuel pump?) Hopefully, you can replace the fuel filter without buying a new pump.

 

[abong]

Are you just getting the tank cleaned, or will you also have it sealed. with that much rust I would be concerned for the future, getting it properly sealed would be your best option (short of buying a new tank). I trust you are going to change any inline fuel filters for the injection system as they might be blocked.

Gary

The service guy said he will send it to a tank repair shop to the cleaning n coating.. i dunno what coating they’re going to use..

The membrane filter in the fuel pump need to be changed as well..

Getting a new tank is the goal, but very costly

 

[abong]

WOW... this is crazy...so much rust (are you sure it is rust?)
There must have been water in the fuel tank for quit some time, previus to you buying it.

Took out a magnet just to test and they stick together.. made of metal I guess..

 

[2daMax]

The tank must have been kept empty for a very long time. Which shop did you go to? Is it Bard?

 

[abong]

The tank must have been kept empty for a very long time. Which shop did you go to? Is it Bard?

It’s a bike shop in Melaka.. didn’t dare to ride to Bard’s..