2012 FJR stalling

[NMRoadRunner]

exactly my thoughts. Dump that dealer, they don't know what they are doing. Tell em to check out this forum next time they get a fjr in with problems. The dealer hate this forum, we know more then their techs do by far.

 

[un4gvn]

The Idle speed is controlled via coolant that passes from the Radiator to the Throttle Body then back. As the coolant warms there is a small wax bead inside the idle speed controller that gets soft and changes the idle position. The port on the side of the Radiator where these connect trap deposits from the coolant sometimes and clog up. Especially after the bike has been stored for a long period of time (sat on the Dealers showroom for a year before selling, etc). I would start by checking for a partial blockage there....

 

[Denver_FJR]

The Idle speed is controlled via coolant that passes from the Radiator to the Throttle Body then back. As the coolant warms there is a small wax bead inside the idle speed controller that gets soft and changes the idle position. The port on the side of the Radiator where these connect trap deposits from the coolant sometimes and clog up. Especially after the bike has been stored for a long period of time (sat on the Dealers showroom for a year before selling, etc). I would start by checking for a partial blockage there....

The wax bead device you're referring to is the cold start air circuit and should not be used to adjust idle once motor has warmed. (Technically, I believe Yamaha calls it "Plunger Control Unit"). If the coolant ports have become blocked due to solidified coolant, I would expect the engine to run at fast idle all the time as no warm coolant would reach the wax motor.

The idle circuit (as others have correctly referenced with diagrams) regulates air into the throttle bodies via a completely different circuit.

 

[Queensland Ken]

 

[un4gvn]

The Idle speed is controlled via coolant that passes from the Radiator to the Throttle Body then back. As the coolant warms there is a small wax bead inside the idle speed controller that gets soft and changes the idle position. The port on the side of the Radiator where these connect trap deposits from the coolant sometimes and clog up. Especially after the bike has been stored for a long period of time (sat on the Dealers showroom for a year before selling, etc). I would start by checking for a partial blockage there....

The wax bead device you're referring to is the cold start air circuit and should not be used to adjust idle once motor has warmed. (Technically, I believe Yamaha calls it "Plunger Control Unit"). If the coolant ports have become blocked due to solidified coolant, I would expect the engine to run at fast idle all the time as no warm coolant would reach the wax motor.

The idle circuit (as others have correctly referenced with diagrams) regulates air into the throttle bodies via a completely different circuit.

You're right. As the wax heats up via coolant the plunger retracts and the idle goes down. The issue usually comes when there is an intermittent or partial blockage in the system. The bike starts to idle too high and someone reaches down and turns the idle adjustment down. Then eventually the coolant warms up or makes it's way past the blockage after riding a while and the plunger retracts. Now the bike ceases to idle correctly.

I know it's a good way down the list of things to check but it is worth taking a look at. I ran into this scenario on multiple FJRs in the last few years...