Question About FZ6's choke

[tuning-forks]

Very educational! Thank you!

I'm sure I got the link to that vid from some other thread on this forum, but can't remember which one.

 

[Motogiro]

I saw a picture where it looked like there was a plug assembly going to the IAC and thought there was some electrical control but it was part of a harness that routed through the assembly.
As Scott pointed out,(reinventing the wheel) I wonder what other advantage the IAC has over the previous tech. of using a conventional choke. Maybe it has to do with more efficient emission development?

 

[toybox]

I think the wax refers to how the plunger in IAC is actuated. Same as in an automotive thermostat, thermostatic wax is used to expand and contract with temperature and actuate a plunger.
Including a link to a video about IAC operation, different Yamaha model but should be similar principles.

All this aside, I don't see how you can substitute electronic control. You would have to move to a stepper motor and re-design a new ECU.

IAC operation

The original manufacturer uses a wax element controlled by water temperature. In my design, I use a water temperature-controlled switch that heats the wax when powered. The advantage of this approach is that it allows me to reduce the length of the coolant flow path and use an electric heater, which makes maintenance more convenient.

 

[toybox]

Good video. It almost makes me want to remove the IAC from my spare engine and disassemble it.

I believe that using a specialized tool would make disassembly easier. Since it is not frequently taken apart, attempting to do so without the proper tool may damage the screws and make reassembly difficult.

 

[toybox]

I saw a picture where it looked like there was a plug assembly going to the IAC and thought there was some electrical control but it was part of a harness that routed through the assembly.
As Scott pointed out,(reinventing the wheel) I wonder what other advantage the IAC has over the previous tech. of using a conventional choke. Maybe it has to do with more efficient emission development?

The advantage is that it is easier to maintain — you only need to check whether it is powered. There’s no need to worry about whether coolant is flowing through or whether any residue remains when replacing the coolant.

 

[tuning-forks]

The coolant method is not just on/off like a switch. There is a transition phase where the plunger is only partially closing the holes.
To do it as well as the stock method, you would need to use something like a thermistor and a variable temperature heater. You need an electronic circuit that will precisely mimic the temperature of the coolant.
I suppose in a hotter climate, it may not be as critical to have the transition phase, and an on/off circuit may not be as big of a problem.
For the reliability problems, you still have the same plunger system and I think it will still have the same issues. As far as I know, the plunger mechanism is sealed off from the coolant. It gets gummed up from other reasons than the coolant. Probably from moisture in the air lines.

 

[toybox]

The coolant method is not just on/off like a switch. There is a transition phase where the plunger is only partially closing the holes.
To do it as well as the stock method, you would need to use something like a thermistor and a variable temperature heater. You need an electronic circuit that will precisely mimic the temperature of the coolant.
I suppose in a hotter climate, it may not be as critical to have the transition phase, and an on/off circuit may not be as big of a problem.
For the reliability problems, you still have the same plunger system and I think it will still have the same issues. As far as I know, the plunger mechanism is sealed off from the coolant. It gets gummed up from other reasons than the coolant. Probably from moisture in the air lines.

I understand, which is why I opted to use the electronic choke typically used in carbureted models. According to my data, there appears to be no structural difference, as both operate using electronically heated thermal wax.
My idea is that when the coolant temperature reaches the activation point of the switch, it will supply power and gradually heat up—similar to how the original system slowly warms up through engine coolant. However, since the expansion rate of the wax may not be exactly the same as the original, I control it by adjusting the activation temperature of the thermal switch. It remains a linear process.

 

[toybox]

The coolant method is not just on/off like a switch. There is a transition phase where the plunger is only partially closing the holes.
To do it as well as the stock method, you would need to use something like a thermistor and a variable temperature heater. You need an electronic circuit that will precisely mimic the temperature of the coolant.
I suppose in a hotter climate, it may not be as critical to have the transition phase, and an on/off circuit may not be as big of a problem.
For the reliability problems, you still have the same plunger system and I think it will still have the same issues. As far as I know, the plunger mechanism is sealed off from the coolant. It gets gummed up from other reasons than the coolant. Probably from moisture in the air lines.

The reason I replaced it was due to concerns about reliability. Since it relies on cooling water for heating, there is a possibility that it might fail after a coolant replacement or that it cannot be tested for faults through power-on diagnostics during inspections.

 

[jjmaine]

Can I ask why it might fail after a coolant replacement?

I'm curious because my bike uses this system (Yamaha Fz6r) and after getting it out of winter storage this spring my bike had a problem and it wouldn't go to high idle when I did a cold start. It would start and idle very low and then the idle would gradually climb to high idle until it got up to temp. Other than that the bike ran perfectly.

It has seemed to get a little better the more I ride it but I'm just trying to understand what my issue might have been? It's a lot easier to troubleshoot a problem if I understand how something works and it various components so I appreciate this thread. I assumed the bike idled high based on the coolant temp sensor, not coolant flowing through the throttle body (IAC).

 

[TownsendsFJR1300]

Can I ask why it might fail after a coolant replacement?

I'm curious because my bike uses this system (Yamaha Fz6r) and after getting it out of winter storage this spring my bike had a problem and it wouldn't go to high idle when I did a cold start. It would start and idle very low and then the idle would gradually climb to high idle until it got up to temp. Other than that the bike ran perfectly.

It has seemed to get a little better the more I ride it but I'm just trying to understand what my issue might have been? It's a lot easier to troubleshoot a problem if I understand how something works and it various components so I appreciate this thread. I assumed the bike idled high based on the coolant temp sensor, not coolant flowing through the throttle body (IAC).

How many miles and how often do you change your coolant?


.

 

[toybox]

Can I ask why it might fail after a coolant replacement?

I'm curious because my bike uses this system (Yamaha Fz6r) and after getting it out of winter storage this spring my bike had a problem and it wouldn't go to high idle when I did a cold start. It would start and idle very low and then the idle would gradually climb to high idle until it got up to temp. Other than that the bike ran perfectly.

It has seemed to get a little better the more I ride it but I'm just trying to understand what my issue might have been? It's a lot easier to troubleshoot a problem if I understand how something works and it various components so I appreciate this thread. I assumed the bike idled high based on the coolant temp sensor, not coolant flowing through the throttle body (IAC).

I’m not exactly sure what the coolant-based choke control system on the FZ6 is officially called, so I’ve been referring to it as the IAC. In my opinion, using coolant to heat the IAC is similar in effect to what happens when coolant isn’t properly maintained—since the small internal passages can get clogged. That’s why I decided to install a temperature switch in one of the larger coolant lines, so I can more accurately detect the engine temperature. Then, using that switch, I can activate a heating element to control the IAC and manage idle during warm-up.

 

[toybox]

Can I ask why it might fail after a coolant replacement?

I'm curious because my bike uses this system (Yamaha Fz6r) and after getting it out of winter storage this spring my bike had a problem and it wouldn't go to high idle when I did a cold start. It would start and idle very low and then the idle would gradually climb to high idle until it got up to temp. Other than that the bike ran perfectly.

It has seemed to get a little better the more I ride it but I'm just trying to understand what my issue might have been? It's a lot easier to troubleshoot a problem if I understand how something works and it various components so I appreciate this thread. I assumed the bike idled high based on the coolant temp sensor, not coolant flowing through the throttle body (IAC).

It’s possible that, due to winter storage, the oil has settled away from the gears and other parts, which might be affecting the IAC plunger’s movement. This could explain why the idle doesn't rise as it should during cold starts.

 

[jjmaine]

I bought my bike w/6k miles and changed the coolant winter before last with Engine Ice (at around 8k miles). The bike had Engine Ice in it when I drained it so it had been changed previously. Now it has a little over 11k miles.

That could explain it toybox, just sticky components from sitting over winter. That would also makes sense why it seems to be getting better the more I start and ride it

 

[tuning-forks]

It’s possible that, due to winter storage, the oil has settled away from the gears and other parts, which might be affecting the IAC plunger’s movement.

There is no oil or gears involved in the IAC operation. Your lack of understanding the basic principles of how this thing works makes me wonder if the whole topic is just a theoretical exercise.
There is not much chance of mating up an electric choke to run the existing IAC plunger and assembly.

If I am wrong, then sorry to have doubted you, but please post some pictures of how you mounted the electric unit onto the stock IAC.

 

[toybox]

There is no oil or gears involved in the IAC operation. Your lack of understanding the basic principles of how this thing works makes me wonder if the whole topic is just a theoretical exercise.
There is not much chance of mating up an electric choke to run the existing IAC plunger and assembly.

If I am wrong, then sorry to have doubted you, but please post some pictures of how you mounted the electric unit onto the stock IAC.

Looks like something was missed in the translation—here’s how I had translated it earlier."你的車輛因為經過冬天存放,我認為機油已經從齒輪脫離以及各零件的潤滑程度不足,有可能是造成IAC推柱無法順暢作動的原因,這將導致怠速在起始時無法增加轉速"

I meant to separate the gears and the IAC components in my explanation, but they were translated together. What I was trying to say is that all mechanical parts require lubrication, and if the bike hasn’t been used for a while, the lack of lubrication could affect how smoothly they operate.
So far, I haven’t been able to find an electronic choke that’s compatible, since its design is different from the commonly used types. I also haven’t been able to identify the brand or manufacturer that made the original idle control unit. I’m assuming it might be Mikuni, so I’ve been looking on Taobao and found a few electronic choke options that might work.

I’ll need to do some custom work to make the cylindrical piece fit correctly—I’ve taken measurements from the original part to guide the process.

 

[toybox]

There is no oil or gears involved in the IAC operation. Your lack of understanding the basic principles of how this thing works makes me wonder if the whole topic is just a theoretical exercise.
There is not much chance of mating up an electric choke to run the existing IAC plunger and assembly.

If I am wrong, then sorry to have doubted you, but please post some pictures of how you mounted the electric unit onto the stock IAC.

The front end of the electronic choke assembly has been confirmed to be similar to this product. However, Taiwan has restrictions on importing goods from China—there are only six tax-free import quotas every six months, and each shipment must not exceed NT$2,000, which is about USD 68.68. So I’ve had to import the parts in separate batches.





Buying affordable Chinese parts in Taiwan is quite troublesome—it’s really unfriendly for people who want to do their own maintenance or modifications. Anyway, here’s the single-sided swingarm I was measuring yesterday. I borrowed a laser level to take accurate measurements.

And this was an issue I ran into after getting it—but it’s already been fixed.

 

[toybox]

There is no oil or gears involved in the IAC operation. Your lack of understanding the basic principles of how this thing works makes me wonder if the whole topic is just a theoretical exercise.
There is not much chance of mating up an electric choke to run the existing IAC plunger and assembly.

If I am wrong, then sorry to have doubted you, but please post some pictures of how you mounted the electric unit onto the stock IAC.

Oops! We ran into some problems.
Oops! We ran into some problems.
That's strange... it seems like I've hit the image upload limit?

 

[tuning-forks]

Well, if you are able to do fabrication and custom work like that, I wish you success. And with the swingarm as well.

But I will remind you about the IAC, it is not the temperature sensor and plunger that has the reliability issue. It is the rest of the IAC unit, which is sort of like a sliding cylinder in the main IAC body. It gets gummed up over time and not because of coolant. Changing the plunger will not solve that problem.

 

[jjmaine]

Inside here it gets gummed up? Is that what might be happening to mine? Doesn't look fun to change or fix since that also controls the TB sync? I have a spare TB that I bought cheap on eBay to work out a lighter throttle spring. I might take apart the IAC and have a look around lol

Sorry to hijack your thread toybox

 

[TownsendsFJR1300]

The early FJRs had a somewhat stiff throttle.

The "fix" for that was to simple, (in this case the left side on the FZ), un-wind the main
circular spring ONE ROTATION. This lightens up the spring tension.

Even thou there's a push / pull throttle cable, make sure the throttle returns on it's
own after the mod.

.