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Up Topic C1 Information / Repairs - Faults & Fixes / Stalling at idle ever trip..
- - By 1ukeinlondon Date 17.10.19 08:50
Hey guys. Since my battery went flat (not sure if it's related) the idle sounds really low and traffic lights and will stall (and start right up after button push) every trip (20mins X2 per day)

I don't want to sink any more money into this C1 than I need to. Hoping someone is clear on what the fix is. I know my mechanic told me my lambda sensor was not good (have replacement) bit not sure that will fix the issue

Thanks all!
Parent - - By rockstedy Date 17.10.19 09:39 Edited 02.11.19 10:32
Have same problem on my bikes. Cleaning, replacing VOD, injector seal didn’t help - hot engine stops without extra throttle. Finally replacing whole inlet unit fix bike. It was throttle position sensor ( potentiometer 5k) which let engine run when hot and disconnected so worth to try it that is the case. It is sealed unit and measuring with multimeter does give correct readings. Moreover experienced similar issue on other bike where engine was running  way to fast when hot causing clutch/belt excessive damage replacing inlet unit  fix it until now.
Parent - - By aware Date 17.10.19 09:45
Random thoughts:
- Battery terminals loose
- Intake manifold cracked
- Loose injector seal
- VDO (need to swap to confirm)
- Valves (rare)
- Spark plug defect or worn
Parent - By HelmetHair Date 17.10.19 09:52 Edited 17.10.19 11:18
my comments on helpful suggestions by aware, and suggested order to check:

- Loose injector seal
good possibility of this, easy to check-spray carb cleaner or brake cleaner around injector seal and see if it affects idle-AT YOUR OWN RISK, this stuff is flammable.

- Battery terminals loose
unlikely (i cleaned and tightened them), but easily checked

- VDO (need to swap to confirm)

- Intake manifold cracked
VERY unlikely

- Spark plug defect or worn
not if it was replaced. if it wasn't, get an Iridium plug to replace it with.

- Valves (rare)
not if they were fixed!
Parent - By HelmetHair Date 17.10.19 09:54
Also, why did battery go flat? Is it an old one?
You may want to look in to checking the voltage at idle to see if generator working properly. Search the forum for yellow wires which should reveal helpful posts
Parent - - By Alexbmwc1 Date 17.10.19 10:02
Hi 1uke,

try to perform the BMS reset procedure :-);hl=reset%20bms

Might help, should help :-)
Parent - - By aware Date 17.10.19 10:19
Just to comment my VDO was broken and suffered same symptoms. Also old member actd (where is he?!) mentioned breakage of VDO's...
Parent - - By patc50 Date 17.10.19 16:40
I had the exact same symptoms and it was a problem with the injector seal - air leaking past the injector.  You can check this using brake cleaner as per HHs suggestion and his caution.  Check the O ring on the injector itself and also the rubber/metal insert that surrounds the injector .... it's not listed as a seperate part.  The rubber on rubber/metal insert shrinks over time.  Can use an automotive sealant or self-amalgamating tape or, in my case, I put an O ring underneath the rubber/metal insert, made sure that the injector was screwed down tight and so far it has worked.

Hope you get it sorted
Parent - - By 1ukeinlondon Date 18.10.19 21:05
Guys thank you all for your suggestions. I wasn't getting notifications so didn't realize people were responding. I have (as HelmetHair will attest) extremely limited capabilities so will read through the posts above and see what I can do.

Battery went flat cause I tried the steering lock and forgot about the light staying on..
Parent - - By 1ukeinlondon Date 19.10.19 18:18
Hi guys, update. After it stalls it's having a harder time starting back up
Parent - - By HelmetHair Date 19.10.19 21:57
Have you tried squirting stuff around the injector?
Did th mechanic change any shims? (Bucket shims)? when he did the valve service?
Parent - - By aware Date 20.10.19 04:38
Does it start with a bit of throttle?
When it starts, it again dies or needs throttle to remain on?
Then it suffers most probably from poor mixture.
Parent - By HelmetHair Date 20.10.19 08:13
Poor mixture most likely caused by bad injector seal...
Up Topic C1 Information / Repairs - Faults & Fixes / Stalling at idle ever trip..

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