Question About FZ6's choke

[toybox]

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.

In reality, the IAC on the FZ6 isn’t a true IAC. Its actual function is only to assist with idle during engine warm-up—and that’s the part I need it to handle. Let me clarify again why I decided to modify it: scale buildup tends to accumulate in areas that are difficult to clean, and switching to an inexpensive electronic choke significantly reduces maintenance costs. It also allows me to adjust the activation temperature based on actual needs, and helps simplify the bike’s external appearance when reworking the wiring and coolant lines.

 

[toybox]

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

View attachment 93475

This is a rough breakdown of the internal structure: on the right side, hot coolant flows in through a narrow channel from the engine and heats the wax hidden inside the blue section. As the wax expands, it pushes the red cylindrical piece on the left side outward. This movement opens a valve, allowing air to enter the throttle body during idle. It also helps with synchronizing the four cylinders, which is a clever part of Yamaha’s design.


However, I think the way this component is mounted on the bracket takes up quite a bit of space. So my plan is to replace the coolant-heated wax element on the right side with an electric heater. The signal for whether the engine has warmed up will instead be handled by a temperature switch installed on a larger coolant hose.
I believe that aside from this component affecting the idle riding feel, the way engine oil coats the transmission gears also plays a role in overall ride quality. Since my region doesn’t experience freezing temperatures, the oil retains better flow characteristics and stays between the gears more effectively.

 

[tuning-forks]

Let me clarify again why I decided to modify it: scale buildup tends to accumulate in areas that are difficult to clean, and switching to an inexpensive electronic choke significantly reduces maintenance costs.

This is the point I am trying to make, you are replacing the side of the assembly that does not have the scale buildup problem. Coolant does not get into the area you show as the red cylinder. You will still need to clean that side up as often, even with electric plunger. The scale buildup is not caused by coolant.

 

[toybox]

This is the point I am trying to make, you are replacing the side of the assembly that does not have the scale buildup problem. Coolant does not get into the area you show as the red cylinder. You will still need to clean that side up as often, even with electric plunger. The scale buildup is not caused by coolant.

I understand that the coolant doesn’t enter the area where the red component is located, but it still affects how efficiently the wax is heated. If too much debris or oil residue builds up in the coolant path, the heat transfer becomes less accurate and reliable.

 

[jjmaine]

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.

.

Not possible on mine because there was only 180° of preload on the spring. I just re-bent the spring tang to have only 90° of preload when installing the throttle wheel and it made it around 25% lighter which is perfect now for me (with the Graves quick turn throttle). Any lighter and I'd be whiskey throttling over bumps lol.