BSA Owners' Club Workshop Discussions

The BSA Workshop => Singles => Topic started by: Barnsey on 30 Oct, 2025, 10:09

Title: The knack
Post by: Barnsey on 30 Oct, 2025, 10:09
Hi All,

  Could someone please advise me on the knack of starting a C15?  I am new to this and am having all the same issues with Bike no 2 (which is supposed to be a runner)  as I did with the first bike before the kick start broke. 

1/ Carb tickled and choke on (concentric carb) 
2/ Ignition on (Ammeter shows discharge) 
3/  Work the kick start around to just after TDC, and then kick.
 

BUT nothing! 

  The next check will be to look for a spark, but this all seems a bit too familiar. 

   What would be wonderful would be if I could find a fellow in my area who could give me a lesson in this. 
Title: Re: The knack
Post by: limeyrob on 30 Oct, 2025, 11:12
You may be flooding it.  Try a small tickle and no choke.  About 1/4 throttle, no more.
If its doesn't start after a few kicks open the throttle fully and kick a couple of times, it should back fire and clear the cylinder, then try again.
How is the spark?
Title: Re: The knack
Post by: Barnsey on 30 Oct, 2025, 16:38
It looks like I might have a small electrical issue.  There wasn't a spark.  I've put the battery on charge and I'll try again tomorrow.
Title: Re: The knack
Post by: limeyrob on 30 Oct, 2025, 19:26
Has it got the "Emrg" setting on the ignition?  It should then start on a flat battery.  The emergency setting starts direct of the alternator and it takes a decent kick of push start and it would run so well but it gets you going.
Have you cleaned the points?  A double sided nail file works well.  Main reason bikes that have been standing don't' have a spark. 
Title: Re: The knack
Post by: V500 on 30 Oct, 2025, 21:17
I must be unlucky, but I've never had any bike start in the EMG position. Aged alt and poor switch connections I suppose.
If the bike's been rewired and a new regulator fitted there's a good chance that this position is now redundant and not connected, too.
Title: Re: The knack
Post by: cdsdorset on 30 Oct, 2025, 22:09
Where are you based?
Title: Re: The knack
Post by: Barnsey on 31 Oct, 2025, 10:09
I'm in Hampshire, near Portsmouth.  A bit of a hike if you are in Dorset.

  Anyhow, I made up a couple of adapter leads to connect up the gel pack battery, and I got the polarity right this time, (DOH!). Also I charged the battery over night.  The upshot is that I now have a healthy looking spark. 

  My mate, who is more experienced in these bikes, is due over in an hour to give me a lesson in kick starting, so I'll let you know how I get on. 
Title: Re: The knack
Post by: Barnsey on 31 Oct, 2025, 11:32
The bike started first prod with Ray's big boots!

I then had a go myself, but no joy with my skinny frame.  I reckon that I am going to be practising.
Sadly rain stopped play for the moment. 
Title: Re: The knack
Post by: limeyrob on 31 Oct, 2025, 13:06
OK, well a C15 should not kick back hard so you can really go for it with little fear of getting a whack.  If you are light then one approach is to stand astride the bike, lean it slightly to the left, jump up and come down with all your weight using your right leg on the kickstart.  You won't fall over because your left foot will come down to the ground when the kick is finished.  Its takes a bit of practice to get the balance but its worth it as jumping up gives you a lot more force and speed coming down on the kickstart.
I have a Matchless 350 single with a competition engine and a magneto so there's no spark if you kick slowly. You could kick it over 20 times with a normal kick and just get worn out. Jump up and hit it as hard as possible and its a first kick starter.  If I've screwed up and flooded it I don't keep trying, I take a break then come back, I'm 70 and have had a heart attack so I only get 3 or 4 goes then I need to recover.
After the heart attack I couldn't start it so I went to the shed and kicked it a few times every few days to build my muscles and technique.  Now 9 months on I can start it first kick.
Title: Re: The knack
Post by: Barnsey on 31 Oct, 2025, 15:35
Sage advice thanks!

 Just one small issue.   I find it difficult to kick when astride the bike.  My feet are quite turned outwards, so I have to twist my leg to the left, and then I clout my knee on the oil tank, OUCH! So..  I reckon I will be starting from the ground. 

I watched an interesting video of a lady starting a B33, and she really did jump on the starter pedal.  That said, I don't want to be lacking as a gent, but she looked to be heftier than my 10 stones. 

   I'll hopefully get to give it another go tomorrow..
Title: Re: The knack
Post by: Barnsey on 08 Nov, 2025, 12:44
I had another practice session at starting the bike this morning. 

It started second kick, with me jumping on the kickstarter, but then stalled. 

Quite a few kicks later it started a second time. It ran well, but then stalled when I let go of the throttle. 

I wonder if the concentric carb needs a bit of setting up.  I gather that the last owner fitted it to sell the bike, so it might need a bit of a tweek.

 More important is that the ammeter wasn't showing as charging.  Maybe it needs a new rectifier.   
Title: Re: The knack
Post by: Derek996 on 08 Nov, 2025, 14:42
Once you get it going hold it on the throttle to keep it running. While doing this screw the throttle stop in a fair bit so that when you back off the throttle it keeps running. Now ease off the throttle stop until you achieve a reasonable tickover speed. You can then adjust the pilot mixture. Slowly screw it in one direction and note if the idle speed increases or decreases. If it decreases turn it in the opposite direction. Usually this will result in an increase in engine speed. If it doesn't the mixture was already ok. If the speed increases keep turning in the same direction until the speed begins to slow. Now turn it back until you find the point that gives maximum speed. This should be the correct pilot setting although I usually find a better throttle response from a closed throttle if the mixture is richened by no more than an 1/8th of a turn. Once you have set the mixture you can back off the throttle stop for a good tickover.
Best way to check the charge is with a meter across the battery. Assuming a 6V system the battery volts should go up to around 7.2V when the engine is revved a bit.
Title: Re: The knack
Post by: Barnsey on 08 Nov, 2025, 14:47
Great! Thanks for the tips.  I'll check the charging first and then look at the carb.
Title: Re: The knack
Post by: Barnsey on 08 Nov, 2025, 15:29
I've just been down to the garage with a freshly charged battery and multimeter.

I kicked the bike over a few times but it didn't want to know, one cough and that was it. 

I've been experimenting with different combinations of throttle, tickle and choke.  No joy just yet. 
Title: Re: The knack
Post by: Barnsey on 08 Nov, 2025, 16:16
I whipped off the saddle.   The rectifier has been bodged.  One terminal had snapped off so somebody had roughly soldered on a wire and chopped up a ring terminal to act as a spade.  Yuck!. 
For the sake of a fiver I will order a new rectifier. 

Another session of kicking. It started once. I let it warm up, with my hand on the throttle, and then backed off the choke, but I let it stall.  After that it didn't want to run. 

The weird bit is that, at this point it got harder to kick over.  I could stand on the kickstart and it wouldn't move.  IS that normal as it warms up? 
Title: Re: The knack
Post by: rhyatt on 08 Nov, 2025, 16:39
I have just been out to the garage and my C15, tickled it and a bit of choke and mine would not start.
they all have variations and these variations change with the weather.
so - choke off , no more tickle and throttle wide open to clear any flooding - sure enough fired straight away.
so maybe - if you have been kicking and tickling - it may be flooded , hold throttle wide open and kick it - it may cough a few times and then fire up roughly and slowly sort itself out as it clears
Title: Re: The knack
Post by: Barnsey on 08 Nov, 2025, 16:44
Okay, thanks!  I'll try again in the morning.
Title: Re: The knack
Post by: limeyrob on 09 Nov, 2025, 17:56
Its possible that now its running the rust and goo is getting worn of the bore and valves and the rings are freeing up so it will have more compression.  Double ended sword, it will start easier but need a harder kick :)