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Up Topic C1 Information / Repairs - Faults & Fixes / Poor starting and idling
- - By patc50 Date 02.04.18 11:48 Edited 05.04.18 08:35
I've mentioned my C1 woes in Andrew's thread (see below) but as they are continuing I thought I'd start a new thread for any suggestions and ideas.  The story so far.........

* Williams 200, 6300 miles, valve gaps corrected in 2016, never had a problem, put it away in July 2016 after trip to Germany, engine started and very short runs on a reasonably regular basis from July 2016 until present day.
* Took it for MOT on 27th March - engine missing and stalling but got home okay.  Suspected old fuel or air entering injector or possibly ignition sensor (as per Leonm's experience)..
* 30th March - pumped out as much of the old fuel as possible, refilled with 5 litres of fresh petrol, put silicone grease around injector o-rings.
* 1st April - bike now taxed, took it for a run, initially it seemed fine no missing or stalling but after a garage stop it would not start.  Starting was difficult (slow engine turnover), when it did finally start it seemed to surge and die (stall), did this a number of times but by keeping the revs up I managed to nurse it home.  Suspected dud battery.
* 2nd April - swapped battery from another C1  - took 3 or 4 presses of starter button to fire up, idling not normal, idling fast then slow then one stall with a slight 'pop' from the exhaust.  Started again (2/3 presses of starter), went for a run and all seems fine, no missing and it didn't stall at lights or junctions but the idling not correct (fast then slow).  However, starting is not as it was in that it takes 3 or 4 presses of the starter button to start. (I will fit a brand new battery tomorrow when the shops open.)

So although it is no where near as bad as it was when I took it for it's MOT, the starting and the idling are not as they were.  Any suggestions or ideas will be most welcome.


Parent - - By rockstedy Date 02.04.18 12:43
It may be Clogged injector or damaged rubber hose inside fuel tank resulting incorrect fuel pressure. Swap first one  from working bike and check my post about hose.
Parent - - By patc50 Date 02.04.18 14:37
Thanks for the info Rockstedy - it's bloomin annoying as the bike seems to run fine apart from starting and idling.  I've searched out your post on the hose inside the tank - looks like a bu***r to get to.  I'm getting a new battery tomorrow and, if still a problem, I will swap injectors and see what happens.  Fingers crossed I won't have to extract the fuel pump!


Parent - - By leonm Date 02.04.18 16:35
a workshop would check fuel pressure and spray pattern with a persistent problem of this type.  either could affect starting and  idling.
the c1 is also sensitive to starting voltage (poor or undercharged  battery or a bad starter motor giving slow cranking speed).
extracting the pump from the tank is a bit tricky but quite easy once you've done it before (like a number of other jobs on the c1!).
Parent - - By aware Date 02.04.18 16:54
My bike was sitting for 5 years and had similar problems before I change battery.
It was idling fine as long as it was jump cabled but never behaved properly until I put a good battery.
Parent - - By patc50 Date 04.04.18 21:43
Update - new battery fitted. Not much improvement although the idling seems more stable but still an occasional idling surge. The starting is no better, still 2 or 3 presses of the starter button before it fires ........ the strange thing being that bike runs perfectly with plenty of acceleration and power.

My next step is to fit a new spark plug and see if that helps. If there is no improvement I will swap the injector with the one from my Wasp C1 and see what happens.

As I will be using this bike for a trip to Germany, I’m determined to get it running perfectly.

Parent - - By aware Date 05.04.18 05:39
Other things to check: seals around injector (check for leaks) and valves.
Parent - - By patc50 Date 05.04.18 08:34
Hi Aware - thanks for the info.  Valves were checked and tappets/buckets replaced to correct gap in 2016, some 2,500 miles ago, so I'm assuming they are still in tolerance.  I put some silicone grease around the injector o-ring at the start of this investigation so hopefully, no leaks there ........ but as I mentioned above, if a new spark plug doesn't help I will swap injectors to see if that makes a difference.


Parent - - By alunt Date 05.04.18 18:03
Is the starter staying properly engaged while the engine is turning over, or does it sound as if it’s slipping? If it’s slipping it will be very difficult to start but will run perfectly once you get it going.

Have you eliminated the ignition sensor?
Parent - - By patc50 Date 05.04.18 18:54
Hi Andrew - starter seems fine, no slipping and is fully engaged. I’ve not eliminated the ignition sensor yet as I’m going for the easy ones first....... next is spark plug ....... then swap injector ........ and if still playing up I will have to investigate the ignition sensor but was trying to avoid draining the engine oil, sourcing a new gasket etc. But it’s fun isn’t it?!!

Parent - - By leonm Date 06.04.18 08:48
some thoughts, although you probably know this already:
draining of oil a doddle, but avoid damaging the drain plug head. they can be really tight. either one can be used for draining.
motor and bike mfrs. have now gone over to silicone gaskets (not for heads of course) and I would recommend it for this job.  use only a high quality non-acetic-acid type of silicone such as Renault blue or wynns gasketmaker.
Parent - - By aware Date 06.04.18 11:12
Yes gasket glue did the job nicely for me in the same alternator cover.
Parent - - By patc50 Date 07.04.18 12:13 Edited 07.04.18 13:48
FIXED - (I hope!) - I fitted a new spark plug (awkward little blighter) and now the bike starts first push of the button but owing to the weather, I've only had a 2 to 3 mile ride on it.  The idling seems much better although I still get a very minor 'surge' of the revs and only very occasionally .... but perhaps I'm being too picky.  The old spark plug was probably the original as I bought the bike with 900 miles on the clock and I've never changed it, so the spark plug was about 16 years old!  The old one had a gap of a 'slack' 0.9mm, the new one has a gap of a 'tight' 0.8mm.  I think the range of problems was caused by a combination of old fuel, a dud battery and a poor spark.  Fingers crossed it is now sorted.

Thank you to everyone who contributed suggestions, the collective knowledge and the willingness to help is fantastic - thank you.

Parent - - By HelmetHair Date 07.04.18 13:06
Point of order.....
gap is 0.8mm rather than 8mm!
Parent - By patc50 Date 07.04.18 13:47
Correct - thanks for that, I forgot the 'point' .... will edit my post.  A spark plug with a gap of 8mm would be a hefty piece of kit!

Up Topic C1 Information / Repairs - Faults & Fixes / Poor starting and idling

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