Bad Idle and bogging, checked a lot already.

[AirTractor]

Hey guys struggling with an 05 FZ6 with a very poor idle and bogging down with a quick pull of the throttle. Warming up at higher rpm’s it idles fine. But once it comes down to around 1300 it starts bouncing from 800rpm to 1500rpm. If I let it sit and idle it will eventually just die on its own. Read through this forum quite a bit and tried most of the stuff recommended for this issue.
This is what i’ve done so far:
Iridium Plugs
Coolant Change
Oil Change
New Battery
Checked Spark plug caps
New Air Filter
TPS Replaced by dealer
I believe dealer checked fuel pressure, etc they tried to trouble shoot and couldn’t figure it out. Problem seems to be getting worse. Exhaust smells very rich like fuel is not being burned.

Does anyone know what the recommended gaps are for the iridium plugs? I may try gapping them down.

 

[Gary in NJ]

Welcome to the forum (from NJ). How did the coolant look when you changed it?

I don't see a throttle body sync check on that list. I would make sure all 4 are in balance.

If the throttle bodies are in sync, you can check the TB heating block. On the right side of the throttle body sync block - on the back side of the engine - you will see two coolant lines. We have seen over the years that corrosion can accumulate inside this chamber, and when that happens the engine will idle poorly and run rich because the fuel block never reaches the correct temperature (there is a temperature sensor on the left side of the sync block). Remove the two screws from the coolant block and check the condition inside the chamber (looking in towards the sync block). If you find any corrosion go ahead and clean it out.

 

[AirTractor]

Welcome to the forum (from NJ). How did the coolant look when you changed it?

I don't see a throttle body sync check on that list. I would make sure all 4 are in balance.

If the throttle bodies are in sync, you can check the TB heating block. On the right side of the throttle body sync block - on the back side of the engine - you will see two coolant lines. We have seen over the years that corrosion can accumulate inside this chamber, and when that happens the engine will idle poorly and run rich because the fuel block never reaches the correct temperature (there is a temperature sensor on the left side of the sync block). Remove the two screws from the coolant block and check the condition inside the chamber (looking in towards the sync block). If you find any corrosion go ahead and clean it out.
View attachment 93370

Okay thank you I will check it out! The bike was sitting a lot from the previous owner so that could make sense.

 

[AirTractor]

Welcome to the forum (from NJ). How did the coolant look when you changed it?

I don't see a throttle body sync check on that list. I would make sure all 4 are in balance.

If the throttle bodies are in sync, you can check the TB heating block. On the right side of the throttle body sync block - on the back side of the engine - you will see two coolant lines. We have seen over the years that corrosion can accumulate inside this chamber, and when that happens the engine will idle poorly and run rich because the fuel block never reaches the correct temperature (there is a temperature sensor on the left side of the sync block). Remove the two screws from the coolant block and check the condition inside the chamber (looking in towards the sync block). If you find any corrosion go ahead and clean it out.
View attachment 93370

so I checked the plugs and gapped them down into spec which helped a little bit. I have since removed the coolant part of the sync block. I attached a photo. It looks like there is some corrosion behind this brass fitting? Is it supposed to move or be able to come out. I don’t want to break anything. The haynes manual doesn’t go into much detail about overhauling the sync block and cleaning it. On the fuel side of the block it seems clean. Any advice?

 

[Gary in NJ]

I think the brass piece is pressed in. Try flushing it with brake cleaner from the hose fitting side. There was an entire thread on this subject from 4-5 years ago, but a lot of the site history has been lost.

 

[AirTractor]

I think the brass piece is pressed in. Try flushing it with brake cleaner from the hose fitting side. There was an entire thread on this subject from 4-5 years ago, but a lot of the site history has been lost.

Yea I sprayed some carb cleaner through those fittings, nothing really came out. I'm trying to figure out how this system works, the coolant warms up the brass piece which seems to do something? I tried hitting it with a heat gun to see if it would move wasn't sure if its like a thermostat or something.

 

[AirTractor]

Just for anyone looking for solutions or wondering. But the bullet and replaced both Ignition coils and all the leads. Problem solved so far.