Issue: Idling at 2500-2900rpm when in gear

[zoeed]

Hi All,
I Just got off my bike, after a short ride to work. It had been in the garage for about 20 days.
My S10 has been perfect in the 20000miles that I have ridden, until this morning.
While in gear, it idles high around 2500-2900 rpm when in gear (all gears)
In neutral it would go back to its normal idling speed.
I noticed that my bike lost compression a few times when I blipped it during the first few miles of my morning ride.
I have a number of mods done to it which could change the stock parameters:
O2 sensor eliminators
Two Brothers exhaust
K&N Air Filter
My country recently converted to 92RON & 97RON fuel

I have come up with some answers to my problem through searching:
1- Could be a spark plug issue (replace plugs)
2- clutch dragging (install new plates)
3- fuel filter choke (replace fuel filter)
4-fuel itself (add fresh fuel)

Any help in identifying the problem would be great .
Thanks in advance
Regards

 

[Dogdaze]

Could be as simple as replacing the battery, others have found that replacing with a new or the higher YTS14 battery cured their idle issues, worth a shot.

 

[zoeed]

Ooo...
I put in a Shorai 18amp couple of months ago.
Maybe the battery needs a deep cycle recharge.
Btw the thing cleared itself out on my way back.
A low battery voltage may have charged one way to work....
I'll need to wait and see what it does in a few hours when I go to work again.

 

[Cycledude]

"I noticed that my bike lost compression a few times when I blipped it during the first few miles of my morning ride."

Could you explain this further , sorry I simply don't understand.

 

[2daMax]

"I noticed that my bike lost compression a few times when I blipped it during the first few miles of my morning ride."

Could you explain this further , sorry I simply don't understand.

Sounds like the Throttle Sync is out.

 

[trainman]

long shot but simple to check, I know clutch position affects mapping at least on gen 1 bikes, check clutch lever switch ok

 

[JRE]

Sounds like the Throttle Sync is out.

This was my first thought...

 

[Cycledude]

Sounds like the Throttle Sync is out.

He said it lost compression, How could throttle sync affect compression ?

 

[OldRider]

He said it lost compression, How could throttle sync affect compression ?

I don't think he's talking about compression in the same way we do. He said it lost compression when he bliped the throttle, maybe lost power ???

 

[Don in Lodi]

Hi idle in gear, normal in neutral? Anything I can think of would have the same idle throughout. I can't see how a battery would affect idle tho. Once started you can disconnect the battery and not have an effect on idle.

 

[Dogdaze]

Don, I've had a different experience, if I disconnected the battery the bike shuts down, could it be that as in EU we have immobilisers and once power is cut then ecu shuts down?

 

[WJBertrand]

Could the ECU be raising idle speed in an attempt to maintain system voltage in the case of a flat battery?

 

[Don in Lodi]

It's not that smart.

 

[Kevhunts]

It's not that smart.

It's not? Does the ECU not control the voltage regulator? Idle speed control? Ignition timing & advance? Newer gen turn signal rate, grip heaters?

I'd say that's pretty smart.

FYI...Disconnecting the battery on a modern ECU controlled system that is running is simply asking for ECU self destruction.

 

[2daMax]

He said it lost compression, How could throttle sync affect compression ?

I take it that he meant 'compression', or, felt a loss of power.

 

[2daMax]

Hi idle in gear, normal in neutral? Anything I can think of would have the same idle throughout. I can't see how a battery would affect idle tho. Once started you can disconnect the battery and not have an effect on idle.
[/quote

A dying battery may introduce an additional electrical load. And this may trigger the ecu to react. Just guessing for the S10. My car does that when electrical load is increased such as turning on the lights. The idle would be higher by about 100 revs.

A faulty plug coil would cause the idle to go out of normal....usually a lot higher.

 

[Don in Lodi]

It's not? Does the ECU not control the voltage regulator? Idle speed control? Ignition timing & advance? Newer gen turn signal rate, grip heaters?

I'd say that's pretty smart.

FYI...Disconnecting the battery on a modern ECU controlled system that is running is simply asking for ECU self destruction.

Voltage regulator is self contained. At the very most, and I don't think it does in this case, the ecu sends a ground signal to energize the regulator, on/off duty cycle. Idle, yes. Timing, yes. Turn signal, no, that has it's own relay. Grip heaters, I don't think so. I believe that's handled through what would be called a bcu in the dash. As long as the generating system is running above 10 volts, in my experience, the engine should continue to run.

 

[2daMax]

Just something came to mind. Vacuum leaks. Check the left TB vacuum rubber cap. I see mine is going to give way.