Stepper motor removal

RocketmanBristol

Supercharged
Joined
Jul 23, 2017
Messages
427
Ride
2004 Rocket 3
Evening guys The almost three year anniversary of trying to get the Rocket running exceptably continues....... after much advice from you guys and continual fettling I’m at the point of covering her in fuels demand setting her alight ,breaking her as she’s probably worth more in parts or continuing down the love/ hate relationship I have with this bike.
Have replaced all the usual suspects as in primary TPS, map hoses and rubber caps on the throttle bodies, cleaned and balanced the throttle bodies,return springs and stepper to within an inch of their life’s and still have the wandering never stable Rocket tick over ,absolutely love this bike but hate that when I’m heading into a corner the tick over decides it’s going to make life interesting and not shut down making the whole experience a little like a Friday night in the 70’s riding home on a Kawasaki triple!
Having read every bit of this forums advice on the subject I decided to physically remove the stepper motor and stash it in the emp space that was the air box along with the now relocated coolant overflow tank to keep it company.
The good bit is the bike runs the best it ever has in my ownership, ticks over beautifully ,engine brakes whilst blipping down the gearbox and the only ass twitching comes from my own riding limitations not the ever increasing idle speed.
But like most things owning a Rocket ,solving one problem seems create another...........with the stepper stashed under the seat it continually sounds like it’s trying to do something,unfortunately it sounds like I have the wife’s rabbit with me!
Is there anyway to disconnect without getting the warning light/fault code, is it normal for the stepper to sound like it’s working all the time or is that a fault in itself?
 
My post isn’t meant to be negative.....but fixing the idle hunting is where I’d spend my time. The Ecu wants to vary idle based on temp etc. modern Efi engines all have some variant of this.

It pains me to see folk just pulling something because they can’t sort it.

Anywho, good luck dude, hope ya get it running kinda right.
 
Hi,

I understand your frustration. Could it be you just have a dodgey map? I downloaded a map once that didn't go smoothly, though I didn't notice and she ran like a pig. Re loaded a different map but similar and it made all the difference.
Once other thought is a leaking hose/air leak weakening the mixture on tickover. That one may not be as likely as the O2 sensor should compensate. Do you still have an O2 sensor? If so could that be iffy?

Good luck and top marks for keeping at it.
 
Sounds like you stepper motor may be cycling under your seat like it does when starting.
Don't other people simply disconnect it from power when removing it completely from their bike like @sonny did?
Aren't there a number of air pressure sensors as well as the induction air temp one that would effect 'choke' type idle fueling?
Could it also be an intermittently faulty sensor, plug or wiring issue to/from sensors.
 
You said you addressed the MAP hoses, but did you replace the MAP sensor? Mine was idling odd and shutting down completely when coming off the throttle. I battled it for a whole riding season before replacing the MAP sensor.
 
Hi,

I understand your frustration. Could it be you just have a dodgey map? I downloaded a map once that didn't go smoothly, though I didn't notice and she ran like a pig. Re loaded a different map but similar and it made all the difference.
Once other thought is a leaking hose/air leak weakening the mixture on tickover. That one may not be as likely as the O2 sensor should compensate. Do you still have an O2 sensor? If so could that be iffy?

Good luck and top marks for keeping at it.

Thanks Blackthou, Have used a few maps ,back on Hanso 20228 if I remember correctly, runs as well as it ever has.
O2 removed and plugged with bypass.
 
Sounds like you stepper motor may be cycling under your seat like it does when starting.
Don't other people simply disconnect it from power when removing it completely from their bike like @sonny did?
Aren't there a number of air pressure sensors as well as the induction air temp one that would effect 'choke' type idle fueling?
Could it also be an intermittently faulty sensor, plug or wiring issue to/from sensors.

Cycling is exactly what it sounds like ,thanks, but should it do it continually? If not maybe that’s my problem. Even though many say you should keep all the sensors,electronics intact, if it makes the bike rideable I’m happy without it.
Just removing it throws a fault code and hence the warning light being on ,which is my original question on how/ if it can be switched off.
 
You said you addressed the MAP hoses, but did you replace the MAP sensor? Mine was idling odd and shutting down completely when coming off the throttle. I battled it for a whole riding season before replacing the MAP sensor.

Map sensor was replaced some time after the rubber hoses, what’s frustrating is it never throws any codes until I actually remove something, would have thought the old girl would of confessed after nearly three years together lol
 
If your RPM's are wandering at speed it shouldn't be the ISC unless it is broken. And no, it shouldn't be making noise after bike is warm. Was it replaced??
Are you sure the noise is the ISC and not the secondary stepper?
Maybe replace the throttle cable or at least lube and adjust to spec.
A short somewhere could cause ECM wackiness.
Is it repeatable or totally random?
I know you said you cleaned the throttle control area but I had a big beetle get wedged in there once and RPM's went from 900 to 1200 to 2000 over an hour.

I'm no mechanic but I did unhook my Primary Stepper Motor and tucked it into the area where the plenum was and into the rubber oval leading into the battery box but not inside my nice toolbox/glove/snack box. PS. My water bottle is under left side cover.

NOTE: IF you do decide to remove it make sure to also take out some other parts of the assembly to avoid
what happened to me. See pictures below.

I set the idle manually and everything was fine and took it for a ride. I hit a bump 50 meters down my street and the piece that rotates flipped
around and caused the bike to go to 100% throttle. I had pulled in the clutch just as it happened so no wheelie and I hit the kill switch immediately. Scary and loud!

I had to push it home and removed the other bits and have never had any issues since.
If cold, I just hold the throttle until its warm or set the manual cruise control to 1,000 RPM for a minute.

"Primary Throttle Stepper Motor = ISC
Stepper motor used to vary throttle opening at idle and when the engine is cold."


"Second throttle stepper motor - situated between the throttle bodies for numbers one
and two cylinders. In response to direction from the ECM, the second throttle stepper motor moves the second throttle spindle to the
position directed by the ECM. The second butterfly epitomises engine torque by maintaining intake air flow speed.
It does not act as a choke for cold start purposes."

I haven't heard of issues with that one and the secondary butterflies wouldn't cause high idle - especially if you set them to 100% open in the tune.

steppermotordiagram.jpg

steppermotordiagram2.jpg
 

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If your RPM's are wandering at speed it shouldn't be the ISC unless it is broken. And no, it shouldn't be making noise after bike is warm. Was it replaced??
Are you sure the noise is the ISC and not the secondary stepper?
Maybe replace the throttle cable or at least lube and adjust to spec.
A short somewhere could cause ECM wackiness.
Is it repeatable or totally random?
I know you said you cleaned the throttle control area but I had a big beetle get wedged in there once and RPM's went from 900 to 1200 to 2000 over an hour.

I'm no mechanic but I did unhook my Primary Stepper Motor and tucked it into the area where the plenum was and into the rubber oval leading into the battery box but not inside my nice toolbox/glove/snack box. PS. My water bottle is under left side cover.

NOTE: IF you do decide to remove it make sure to also take out some other parts of the assembly to avoid
what happened to me. See pictures below.

I set the idle manually and everything was fine and took it for a ride. I hit a bump 50 meters down my street and the piece that rotates flipped
around and caused the bike to go to 100% throttle. I had pulled in the clutch just as it happened so no wheelie and I hit the kill switch immediately. Scary and loud!

I had to push it home and removed the other bits and have never had any issues since.
If cold, I just hold the throttle until its warm or set the manual cruise control to 1,000 RPM for a minute.

"Primary Throttle Stepper Motor = ISC
Stepper motor used to vary throttle opening at idle and when the engine is cold."


"Second throttle stepper motor - situated between the throttle bodies for numbers one
and two cylinders. In response to direction from the ECM, the second throttle stepper motor moves the second throttle spindle to the
position directed by the ECM. The second butterfly epitomises engine torque by maintaining intake air flow speed.
It does not act as a choke for cold start purposes."

I haven't heard of issues with that one and the secondary butterflies wouldn't cause high idle - especially if you set them to 100% open in the tune.

steppermotordiagram.jpg

steppermotordiagram2.jpg
 
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