Idle problem solved

contours · Jun 11, 2019

TonyA said:
I am running the resistor plugs , not just disconnected O2 sensors. 330 ohm and 1 Meg ohm , one is for the heater pins the other for the signal pins .

I purchased the resistor plugs a while back. Can't remember if there was a problem with the thread size, though. One more question - how do you disable the IAC?

TonyA · Jun 11, 2019

2 completely separate projects. Do one thing at a time . Just a while back you said you were happy with your idle , then why remove the IAC. I think a good project is to install the heat insulators first. Go back and look at the threads , make sure you want to do this.

contours · Jun 11, 2019

I am indeed happy with my idle. Okay - makes sense now.

Britfan60 · Jun 12, 2019

Im not having as good an experience as Tony. My bike stays running after second or third attempt as opposed to first on most cold starts. Not a big deal. At first i thought tbe ECU had to relearn the lack of the O2 sensor. I still get the 3700 to 4200 crunchy vibe. The bike lowers too 800 rpm and stalls at stops for the first mile or two, like its taking forever to warm up. Ive gotten as low as 36 mpg on easy rides but am averaging 40 mpg on more aggressive rides. Go figure that one. That said, once warmed up, I get a lovely steady 1200 but up to 1400rpm after a thrashing. Overall, Im happy. Its running fairly well. I still wish we had more efficient mapping and stop having to figurebout improvements with mixed results.

TonyA · Jun 12, 2019

It sounds like you are having the text book idle issues . If you have the inclination , you can remove and clean out the Idle motor. Take that black cap off and give it a good swabbing with solvent alcohol etc.. Or replace the IAM assy . Or take one of the fix routes explained in these threads. It sounds to me like you have all of the bad symptoms . Have you or anyone else adjusted your throttle body stop ? I ask because if this is out then it will cause cold stalls or excessive high idle . I can understand your frustration , I was frustrated too. Some of these bikes give more trouble than others. Have your mechanic read these threads and have a go at fixing it. The O2 sensor delete has been misunderstood by many. It does not fix everything. One specific issue namely the gurgle at mid 3000 rpm steady state cruise . Your bike can be repaired , rent that van and make an appointment with David C.

BritTwit · Jun 12, 2019

Britfan60 said:
Im not having as good an experience as Tony. My bike stays running after second or third attempt as opposed to first on most cold starts. Not a big deal. At first i thought tbe ECU had to relearn the lack of the O2 sensor. I still get the 3700 to 4200 crunchy vibe. The bike lowers too 800 rpm and stalls at stops for the first mile or two, like its taking forever to warm up. Ive gotten as low as 36 mpg on easy rides but am averaging 40 mpg on more aggressive rides. Go figure that one. That said, once warmed up, I get a lovely steady 1200 but up to 1400rpm after a thrashing. Overall, Im happy. Its running fairly well. I still wish we had more efficient mapping and stop having to figurebout improvements with mixed results.

Takes me 3 starts usually to get the bike to idle as well. Weirdly, every once and awhile the thing starts perfectly goes to 2000RPM, then slowly after about 15 seconds, drops back to a nice 1200rpm idle. It does this to piss me off, I'm sure. And it's working.
Just don't understand the inconsistency.

It's as if the bike has a learning disability.

I wonder if I can get a handicap plate for the bike?

TonyA · Jun 13, 2019

If you have a dual seat you have got a clear path to the New Omex upgrade . I have heard that the idling issues were a part of the reason they switched to it. You also have the SC 400 Delta route and if you are willing to start with the base map and go to a tuner ? You will need all the items that lcrken and iwilson purchased to do this , plus tuner and dyno time . You can also try your hand at some of the other idle fixes in these threads , which work as you now know .

Britfan60 · Jun 13, 2019

Actually, I'm not frustrated at all. Just not having the same experience as you. These symptoms of cold stalling are intermittent. Sometimes the bike is flawless start to finish. The cold stalls only started after the lamda delete. Still worth it. I no longer get the high idle hecause I monitor the IAM flange. As for the 40mpg...I can live with that. The 3700 vibe has always been there regardless of mapping. Compared to what was, I'm a happy camper....so far. Oh...and Fred and I both have mono posto.

Peter Smith · Jun 13, 2019

New fault?
2018 Sport 50th, 1040 miles so far. The bike's always dropped to tick over when I'm riding and pull in the clutch, went out a couple of days ago and it started stalling, blipping the throttle helped a bit, but that wouldn't always catch it. EML light came on it would re-start, it needed to several times to get me home. I'm hoping for a dry day to see if it's still doing it, but it's been raining here the last few days. English summer.

Anyone else had this? I can't be the only one... Thanks Pete

TonyA · Jun 13, 2019

You have a new Euro 4 bike. It’s best if you go back to your dealer and have them check the errors for you. In time all the fixes will be available. We don’t have any experience with Euro 4 except what we read here from England and Europe. There are several Euro 4 owners on this forum and hopefully they will chime in . But as was said earlier , its probably something simple .

ntst8 · Jun 19, 2019

Had a nice day out at the weekend, 2 hours of back road riding and i was at the door of a certain mr iwilson.
Nice coffee followed by an hour or two, or three in the garage chatting, comparing bikes, a bit of testing.
Sadly the bend in my shorty mufflers defeated the exhaust gas probes and we couldn't get any useful exhaust gas readings to compare. Ian did have a bluetooth do da which plugs onto the OBD outlet and via a phone App shows some of the goings on in the ECU (SC in my case). The one item which stood out was that my throttle was showing as 28% (i think, or was it 18% - working from patchy memory here) open at idle. Presumably a factory/workshop trick from the dealer visit in Feb, to reduce O2 sensor effect on idle?
As for idle, wow, a side by side comparison is chalk and cheese. Post the Feb workshop visit mine runs 1200 cold (or sometimes wont idle initially), 1600 hot but doesn't sound comfortable and will sometimes surge. Ian's bike is staggeringly good by comparison, it is hard to imagine his could idle any better.
Unrelated but also noticed my primary is very noisy by comparison - i have spare springs on the shelf.
Will see if my ECU tolerates plugging of the IAC/cross tube once my rego runs out at month end. One step at a time.

richard-7 · Jun 19, 2019

ntst8 said:
Had a nice day out at the weekend, 2 hours of back road riding and i was at the door of a certain mr iwilson.
Nice coffee followed by an hour or two, or three in the garage chatting, comparing bikes, a bit of testing.
Sadly the bend in my shorty mufflers defeated the exhaust gas probes and we couldn't get any useful exhaust gas readings to compare. Ian did have a bluetooth do da which plugs onto the OBD outlet and via a phone App shows some of the goings on in the ECU (SC in my case). The one item which stood out was that my throttle was showing as 28% (i think, or was it 18% - working from patchy memory here) open at idle. Presumably a factory/workshop trick from the dealer visit in Feb, to reduce O2 sensor effect on idle?
As for idle, wow, a side by side comparison is chalk and cheese. Post the Feb workshop visit mine runs 1200 cold (or sometimes wont idle initially), 1600 hot but doesn't sound comfortable and will sometimes surge. Ian's bike is staggeringly good by comparison, it is hard to imagine his could idle any better.
Unrelated but also noticed my primary is very noisy by comparison - i have spare springs on the shelf.
Will see if my ECU tolerates plugging of the IAC/cross tube once my rego runs out at month end. One step at a time.

Split gear spring is almost always the noise culprit. CNW has a tension setting tool. Just have to buy the spring from norton. Word of caution; its really easy to over tension and the only fix is a new spring so be patient while doing. With the primary cover off its easy to check and also check your ring gear bolts. Older bikes they used to break. So a loose ring gear can also cause noise. If noise is from the timing side (rh cover) then noise is often from timing chain tension.

ntst8 · Jun 19, 2019

Thanks Richard, i have a full set of tools from cNw i just keep riding it rather than working on it.

richard-7 · Jun 20, 2019

ntst8 said:
Thanks Richard, i have a full set of tools from cNw i just keep riding it rather than working on it.

definitely check your ring gear if you think the noise is getting worse from primary side. There is a thread on here about it. If it has always been noisy and not getting worse since day one then that’s just the regular engine sound.

Glenn Harman · Jun 20, 2019

Peter Smith said:
New fault?
2018 Sport 50th, 1040 miles so far. The bike's always dropped to tick over when I'm riding and pull in the clutch, went out a couple of days ago and it started stalling, blipping the throttle helped a bit, but that wouldn't always catch it. EML light came on it would re-start, it needed to several times to get me home. I'm hoping for a dry day to see if it's still doing it, but it's been raining here the last few days. English summer.

Anyone else had this? I can't be the only one... Thanks Pete

The same fault I am experiencing repeatedly. 2019 Cafe Racer 50th. Registered 2 months ago. 60 miles..

Peter Smith · Jun 22, 2019

At least with this fault you can get yourself home, mine was taken back to the dealers this week for this and it's second service 1150 miles, they changed the head temperature sensor and map sensor, said if that doesn't cure it to take it back and they'd replace the idle air motor.
Cut out when dropping to tick over 4 times on the way home 44 miles or so. They've some iam's on order from Norton......
Impressed with the dealers service.

Portofino Norton's Garage · Mar 22, 2021

Hi Iwilson and all, I red all this quite interesting thread, having of course the same or similar troubles on my 961 SE. I understood how you blocked the pipe connecting the two cylinders port but I'm not perfectly confident on what you mean with removing the whole IAC valve. Do you mean:

1) remove the whole IAC body with relevant tubes?
2) plug the fit for IAC admitting tube on the airbox?
3) disconnect the electrical plug to IAC valve and leave it somewhere in the bike detached? No claims from the ECU?

sorry for asking these details but I would take advantage of your skills, avoiding boring experiments . Thanks a lot in advance for your patience.

iwilson · Mar 22, 2021

Yes, mine is around 1,100 hot and 850 cold. Occasionally it will die from a cold start, although I usually give it a little blip to kill the oil pressure light, which can linger for a few seconds.

Portofino Norton's Garage · Mar 23, 2021

that's absolutely a good result iwilson. But can you please comment on my bullet list 1), 2) and 3)?
I want to be sure what I have to do.

cliffa · Mar 23, 2021

Portofino Norton's Garage said:
that's absolutely a good result iwilson. But can you please comment on my bullet list 1), 2) and 3)?
I want to be sure what I have to do.

As far as I'm aware I think you have point 2 slightly wrong. You need to plug (not cap) the passageway where the IAC normally connects to the throttle bodies, so there is no path between them otherwise the mixture robbing will continue. See earlier in the thread the red bung which iwilson used.

Idle problem solved

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