Idle Speed Adjustment-ST1300

[Andrew Shadow]

@Andrew Shadow , I think you inadvertently uploaded the wrong photo - that is a photo of the preload adjuster.

The mistake is not that it is the wrong photo, it is the wrong photo in the wrong thread. There wasn't supposed to any photo at all so I have deleted it. There was only supposed to be a link to your original post containing the same pictures that you have just posted here.

That photo was for another thread where I asked you a question about the smuggler if you have a chance- https://www.st-owners.com/forums/threads/need-advice-to-remove-battery.70037/page-2#post-2321463

 

[Igofar]

True Michael, however the manual instructs you to use a driver to operate the cable, and for a good reason, the knob can be broken and twisted off the cable. Using a JIS driver is safer,

 

[Ryan_B]

Quick question on the same topic. Mine idles around 850-900rpm even from a "cold" start. It never stalls or anything and our ambient air temperature is around 75-80F in the morning. Is that normal? It isn't stumbling, but it isn't exactly a healthy, smooth idle either (until I reach 3 bars on the temperature gauge).

If I recall, over winter it would warm at higher RPMs, so I assume it is just reading current radiator and air temperatures and doing its thing. Just wanted to verify that others have noticed this as well.

Thank you!
-Ryan

 

[CYYJ]

...Mine idles around 850-900rpm even from a "cold" start.

Hi Ryan:

The Service Manual (page 1-6) specifies an idle speed of 1,000 RPM ±100 RPM. So you are not too far off spec, but if you wish to adjust things, target 1,000 RPM.

My guess is that the determining factor when Honda set the idle RPM specification was maintaining alternator output at idle.

The engine should idle significantly faster than 1,000 RPM following a cold start, but I believe the purpose of that is to rapidly increase catalytic converter temperatures so that engine emissions are reduced as quickly as possible. There is a complex mechanism that includes starter valves & a wax plug device that manages this fast idle following a cold start - but that's a whole different topic.

Michael

 

[Andrew Shadow]

Ryan:
I would not consider that to be a normal cold start RPM even at those ambient temperatures. With a completely cold engine, i.e., the first start up of the day, the cold idle speed should be higher than that. At that ambient air temperature, I would expect to see somewhere in the 1500 RPM range for at least a short time before it begins to drop to base idle RPM.

Base idle on a fully warmed up engine should be 1,000 RPM +/- 100. Mine idles at about 1050 judging by the motorcycle's tachometer. This keeps it close to 1,000 RPM when the radiator cooling fans are running. I can't be certain, but it is possible that having a base idle that is to low is affecting the cold start idle speed. Before you attempt anything else, I suggest that you go for a ride to fully warm up the engine. Once the engine is at full operating temperature, adjust the base idle to the correct speed, then see how it reacts on the next cold start.

 

[Ryan_B]

Thank you Michael and Andrew. I did see that the 1000rpm in the service manual, I was hoping there was a specific "warm up" rpm that I was overlooking. I will adjust it up a little to get it closer to 1000rpm indicated on the tach and see if that does anything for my cold start. It is not necessarily running bad it is somewhat "loping" a little and I have seen a couple of other threads where it warms to operating temperature within 5 minutes. Mine doesn't hit 3 bars until closer to 10.

I am 95% certain that it was close to 1500rpm+ over winter on cold start. I recall not needing to use my throttle to turn around in my driveway because it was idling higher.

Thanks again! I will report back and let you know what I find out.
-Ryan

 

[Igofar]

Another possibility could be that you have a 5 year old bike that has been sitting in a crate somewhere, and all the fluids are old.
Every 2016 PD bike that I've had come through lately has had Jello in the clutch master cylinder and slave cylinder, and brake system.
The coolant may have degraded as well, the FSM calls for replacing the coolant every two years or XX miles etc.
You may also want to remove the two large hoses from your radiator, and see if you have black paint blistering up and clogging up your coolant system.
The vendors who make the radiator paint the inside of the pipes causing issues. This paint should be removed with a plumbers brush.

 

[Ryan_B]

The coolant may have degraded as well, the FSM calls for replacing the coolant every two years or XX miles etc.
You may also want to remove the two large hoses from your radiator, and see if you have black paint blistering up and clogging up your coolant system.

Hi Larry,
Yeah - I considered that. I am planning on flushing it out this winter and inspecting the thermostat. I didn't think it would prevent the computer from increasing the throttle to warm the engine though. I have been wrong before though. ;-)

Thank you,
-Ryan

 

[Igofar]

Hi Larry,
Yeah - I considered that. I am planning on flushing it out this winter and inspecting the thermostat. I didn't think it would prevent the computer from increasing the throttle to warm the engine though. I have been wrong before though. ;-)

Thank you,
-Ryan

T stat stuck open would cause ecu to think it was not warmed up and try to adjust fuel etc.
Clogged idle wax lines would not allow flow in the area to warm valve enough to work correctly .

 

[Andrew Shadow]

T stat stuck open would cause ecu to think it was not warmed up and try to adjust fuel etc.
Clogged idle wax lines would not allow flow in the area to warm valve enough to work correctly .

A defective thermostat and/or clogged SE thermal valve coolant lines will cause the engine to remain at elevated idle speeds longer than usual. This is because a higher engine temperature needs to be maintained for a longer period of time before the SE thermal valve will see enough heat to react and begin to allow the RPM to descend to warm engine base idle speed. Neither one would prevent a cold engine from achieving fast idle on cold startup.

A defective SE thermal valve, or binding linkage of the SE thermal valve, would negatively affect proper cold fast idle RPM. Appropriate fast idle would not be attained, or descending to base idle RPM in a timely manner would be delayed, when either condition is present. These symptoms do not necessarily mean that the SE thermal valve is defective. Igofar has often found that the problem was binding linkages, not the valve being defective. He has successfully corrected the problem on several by cleaning and lubricating the linkage.

Based on your earlier comment about how long it takes to get to three bars on the temperature gauge when starting from a high ambient air temperature, I suspect that you probably have the beginnings of a failing thermostat.

 

[OldMcClelland]

I have come upon the above discourse and think this might be what ails my ST.
It is a 2017 PA. I got it from a honda service manager in NH who put about 7000-8000 miles on it.
It ran just fine for the first few hundred miles I had it. Initial start up idle around 1500 for a min or two, then 1000.
Accelerates well. After about 10-15 min of easy riding, the engine speed will stay at 3000-4000, even pushing the bike when I don't want it.
I hit the kill switch and coast to the side. Throttle at the wrist works fine and springs back to its usual position.
My radiator comes up to 3 bars after several minutes. Just last ride, it reached 4 bars, which was unusual, given ambient air was around 36-40 F.

Could my cooling system be wonky, misinforming the CPU for the engine??

Rob

 

[Andrew Shadow]

...... it reached 4 bars, which was unusual, given ambient air was around 36-40 F.

Based on the above statement, my first impression is that the system is low on coolant. Not the overflow bottle, the cooling system is low on coolant.
The temperature sensor might not be fully immersed in coolant causing faulty readings, or the engine really did get that hot because of a low coolant level.
This could also cause the SE thermal valve to malfunction because it is not being heated properly by coolant, so it holds the RPM at cold engine fast idle RPM's.

If it were me, I would start by checking the coolant level.

 

[OldMcClelland]

WILCO

Should I run a flush through the system, if I don't find it low? Do the flushes harm any internals? An Idle Wax Line sounds like a delicate thing.
Rob

 

[Andrew Shadow]

Coolant flushing additives won't hurt anything if it is one that is compatible with aluminium engines. The same precautions regarding aluminum and silicate free that apply to choosing a coolant apply here as well. It won't hurt the SE thermal valve regardless. The wax is contained within a housing that is heated by coolant. Whatever is in the cooling system never comes in contact with the business part of the wax "motor".

 

[OldMcClelland]

ahh, very good. thanks. I hate surprises, especially when I have to remove tupperware to see/get to things.
Rob

 

[OldMcClelland]

I have VERY GOOD news to report!
The coolant level was at about one half. Clean as new, and when I ran my finger up into the radiator connection, it was all clean with no paint flakes I just topped it off while running, then capped it off and let it run for at least 2 cycles of the electric fan. It stayed at 3 bars the whole time. I buttoned it up and took a 2+ hr ride. It was purrfect!!

Tanks!
Rob

 

[core-aggie]

The coolant level was at about one half

I might be confused, as I'm still 1/2 sleepy.

Coolant level was "one half" of what ?
Half of the overflow tank?
Half of the radiator?
Half a bottle of coolant ?
Something else ?

 

[OldMcClelland]

half way down the side tank on the radiator. I haven't seen the overflow bottle yet. That's behind the Left hand tupperware...
I'll check that out on some rainy day. It was a beautiful weekend.

Rob

 

[Andrew Shadow]

I have VERY GOOD news to report!
The coolant level was at about one half. Clean as new, and when I ran my finger up into the radiator connection, it was all clean with no paint flakes I just topped it off while running, then capped it off and let it run for at least 2 cycles of the electric fan. It stayed at 3 bars the whole time. I buttoned it up and took a 2+ hr ride. It was purrfect!!

Tanks!
Rob

Now you need to figure out why the coolant level was low, and correct that.

 

[Mr.E]

Rob, the overflow bottle can be accessed just by removing that small fairing cover on top of the left cylinder head.

It's a bit tricky to see the MAX line so I use a dip stick to measure down to the MAX level.