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Discussion Starter · #1 ·
Wondering if these solenoid-operated valves have an inspection / cleaning / replacement service interval associated with them.

In my automotive experience, these kinds of devices on modern vehicles are prone to wear/sticking/gumming up over time.

Is the Purge Control Valve basically an electrically-actuated (rather than pressure-activated) PCV (Positive Crankcase Ventilation) valve?
 

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No cleaning schedule for those. They're kept fairly clean the way the CBR routes its hoses. I've never noticed any sticking, or when I plugged the system, I never saw any oil or soot in them. I imagine we won't have any problems with them.

As for the purge control valve, it is for the evap canister purge. The PCV is really just a breather hose attached from the crankcase to the airbox.
 
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Discussion Starter · #4 · (Edited)
Idle Air Control Valve Replacement (IACV)

My bike has been stalling a few seconds after cold startup. The service manual constantly refers to the importance of the Idle Air Control Valve (IACV), so I decided to replace it and see what happens. Turns out...this didn't solve the problem.

Edit: turns out, it did solve the problem! Cold start idles at 2000 RPM, drops back to 1750 RPM, then drops to steady hot idle at 1500 RPM...just like it did when new. When it wasn't working, it would cold start at 1500 RPM and then stall.

I can report that it's not a difficult job to replace the IACV.

The part being replaced is located on the Throttle Body, shown in this diagram as assembly #10 .


It's necessary to first remove the seats, side fairings, the fuel tank side covers, and the fuel tank front cover. Then, unbolt the fuel tank at the front and lift it using a 5" / 125mm prop rod. I found it necessary to remove the overflow hose on the left side of the tank to lift the tank up enough to gain access to the IACV.



The IACV is on the right side of the bike, under this silver retaining plate secured by two screws. Before loosening the screws, disconnect the connector seen right above the black dot on the silver retaining plate.


To remove the screws, a T20 Torx security bit (with a hole in tip to provide clearance for the security pin) is needed.


IACV with retaining plate and connector removed.


New IACV "Valve Set", Honda P/N 16430-KYJ-901 (includes valve + O-ring). It's a stepper motor. The black plastic rotor seen at the bottom needs to be gently spun down the shaft until it lightly makes contact with the motor. Before installation, the slot in the shaft needs to line up with the dot on the silver motor casing (or, the slot needs to be located ~160 degrees counter-clockwise (anti-clockwise) from the connector when looking down from the top).


The slot in the black plastic rotor must be aligned with the brass pin seen here on the left inner wall of the IACV port.


Add blue Loctite to retaining screws and re-install retaining plate over IACV. The service manual says 18 in-lb (2 N m). My smallest torque wrench only goes down to 20 in-lb, so I just carefully snugged the screw "tight enough". Be careful, though, the IACV port is cast aluminum.
 

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Mine starting stalling on cold startup about two or three months ago. I bought it new 5/28/14 and it only has 5006 miles on it.

I crack the throttle open a little before hitting the start button and hold it open for a second when starting, Idles a little fast but settles down and don't stall.
 

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Discussion Starter · #6 · (Edited)
^ Yes, I've been doing that as well but it's irritating...throwback to the days of carbs and chokes. Something isn't right; will keep investigating until it runs right again.

Edit: cold start stalling solved after all. See edit in post #4 above.
 

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^ Yes, I've been doing that as well but it's irritating...throwback to the days of carbs and chokes. Something isn't right; will keep investigating until it runs right again.

Edit: cold start stalling solved after all. See edit in post #4 above.
Looks likes I've got a winter project also, changing the IACV.

Thanks for the great tutorial and photos.
 

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Discussion Starter · #8 ·
I think I didn't give the ECM sufficient chance to "learn" the new IACV. After I'd installed it, I started the bike and...stall. Left it over night, bumped it over this morning and...stall.

Went back this evening, bumped it over and...2000 RPM fast idle with no stall. :) Hasn't behaved that way in weeks/months.

I will keep a close eye on it and see if it keeps on behaving itself.
 

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Discussion Starter · #9 ·
Update...the bike is acting unpredictably.

When a successful cold start occurs, the engine immediately goes to fast idle at 2000 RPM after coming to life.

When a cold start stall occurs, the engine only goes to 1500 RPM after coming to life. It then stumbles for an instant and stops dead.

The service manual lists a few things to check. The possibility of a "leaking insulator" is not trivial. This is the plastic collar that connects the throttle body to the engine. The manual is silent on how to check it. It seems like the only way to do so is to lift the fuel tank, remove the airbox, and try to gain 360-degree access to the collar to squirt water on it with the engine running to see if any gets sucked into the intake stream.

In the meantime, I disconnected the battery last night after dinner. I am leaving it disconnected for 24 hours. Before re-connecting, I will try Aufitt's "Ignition On, Ignition Off" procedure and see if this resets the ECU.

I tend to not think that the insulator is the problem. In my experience, vacuum leaks cause erratic idle...which I am not seeing.

Somehow I think that the ECU does not sense the cold engine condition. The coolant temperature sensor is working (at least, I get normal Temperature gauge function). So perhaps one of the other sensors in the throttle body detects the temperature locally at the throttle body. Honda uses cryptic acronyms for these sensors, so it's hard to get a feeling for what they are actually sensing.
 

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Mine started at 1500 rpm yesterday it didn't stall, but engine doesn't sound good at first. Today I got 1400 rpm's and after a few seconds of stumbling the rpm's increased to 2K and every thing was fine. then settled to 1500 rpm.

There are a few YouTube videos on the subject all are short showing the starting and stalling.
The comments give a lot of opinions, but no fixes. One claimed he flogged the crap out of his CBR an it started working fine. Another claimed he switched from premium gas to regular and that fixed his.
 

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Discussion Starter · #11 · (Edited)
Mine started at 1500 rpm yesterday it didn't stall, but engine doesn't sound good at first.
Yes...the engine "hammers" at 1500 RPM cold, as if the ignition timing is advanced too far for the 1500 RPM speed, causing the engine to almost try to run backward. It's like the flame propagation starts and then the too-slowly-rising piston slams into it. When my bike stalls, it almost sounds like the piston hits up against a hard stop inside the cylinder.

This is an interesting explanation of Honda's "PGM-FI".

I'm intrigued about the IAT (Intake Air Temperature) sensor...
 

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About the time my bike started acting up I had switched from regular gas to ethanol free gas which is 90 octane in Florida.

Sunday I filled up with 3 gallons of regular and Monday the bike started ok. Around 1400 or 1500 rpms, seemed kind of low but no stumbling or hammering.

Today bike started normal again no problems at all.
 

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Yes...the engine "hammers" at 1500 RPM cold, as if the ignition timing is advanced too far for the 1500 RPM speed, causing the engine to almost try to run backward. It's like the flame propagation starts and then the too-slowly-rising piston slams into it. When my bike stalls, it almost sounds like the piston hits up against a hard stop inside the cylinder.

This is an interesting explanation of Honda's "PGM-FI".

I'm intrigued about the IAT (Intake Air Temperature) sensor...
Did you ever solve this problem my bike 2012 abs has the exact same issues,put factory exhaust back on and reset ecu,but still the same
 

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meant to say ,ECM,seems to start a bit easier with factory exhaust and reset,but still struggle to idle and as soon as you touch the throttle it dies
 

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It seems to have mostly sorted itself out over time. I am not really having issues any more.
Did you do anything different to the bike?,ive changed the fuel ,and since putting the original exhaust on seems alot better,still idles a bit slow but if i turn it off then on again it seems to adjust to proper,idle
 

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Idle Air Control Valve Replacement (IACV)

My bike has been stalling a few seconds after cold startup. The service manual constantly refers to the importance of the Idle Air Control Valve (IACV), so I decided to replace it and see what happens. Turns out...this didn't solve the problem.

Edit: turns out, it did solve the problem! Cold start idles at 2000 RPM, drops back to 1750 RPM, then drops to steady hot idle at 1500 RPM...just like it did when new. When it wasn't working, it would cold start at 1500 RPM and then stall.

I can report that it's not a difficult job to replace the IACV.

The part being replaced is located on the Throttle Body, shown in this diagram as assembly #10 .


It's necessary to first remove the seats, side fairings, the fuel tank side covers, and the fuel tank front cover. Then, unbolt the fuel tank at the front and lift it using a 5" / 125mm prop rod. I found it necessary to remove the overflow hose on the left side of the tank to lift the tank up enough to gain access to the IACV.



The IACV is on the right side of the bike, under this silver retaining plate secured by two screws. Before loosening the screws, disconnect the connector seen right above the black dot on the silver retaining plate.


To remove the screws, a T20 Torx security bit (with a hole in tip to provide clearance for the security pin) is needed.


IACV with retaining plate and connector removed.


New IACV "Valve Set", Honda P/N 16430-KYJ-901 (includes valve + O-ring). It's a stepper motor. The black plastic rotor seen at the bottom needs to be gently spun down the shaft until it lightly makes contact with the motor. Before installation, the slot in the shaft needs to line up with the dot on the silver motor casing (or, the slot needs to be located ~160 degrees counter-clockwise (anti-clockwise) from the connector when looking down from the top).


The slot in the black plastic rotor must be aligned with the brass pin seen here on the left inner wall of the IACV port.


Add blue Loctite to retaining screws and re-install retaining plate over IACV. The service manual says 18 in-lb (2 N m). My smallest torque wrench only goes down to 20 in-lb, so I just carefully snugged the screw "tight enough". Be careful, though, the IACV port is cast aluminum.
IACV price
 
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