Dear All,
My C15 No 2 has a concentric carburettor with both tickle and choke on it.
When starting from cold, should I use both tickle and choke? Tickle but no choke, or choke and no tickle?
BR, Ian
sometimes - depending on if it is cold from overnight - it may need both tickle and choke.
but if it doesn't start , i find to remove the choke and 1/2 throttle it will go.
I may have flooded it
so - basically , try all options - sorry , couldn't be more precise
Everyone has different ideas. One site I looked at said no throttle until after it catches.
A matter for experimentation to find out what works best for your bike?
From cold I would say always tickle, but how much is a tricky question. Its primes the engine whereas the choke needs suction to enrich. But you may need the choke to keep it running as the tickle is a one off.
I usually tickle then two slow kicks to get the fuel in the cylinder, then the hard kick and ready to put the choke on if its spluttering.
It really is each to his own.
Yep, experience of each individual bike tells you what you need.
What I never understand is "I removed the choke". Why would you?
Indee, and a lot of people just leave a big hole in the cap to wreck the mixture!
Once I figure out what each bike needs to start, should I be able to start it on demand?
I have visions of riding to the cafe for a coffee, and then not being able to start the bike in order to ride home.
If you can't "start it on demand" then all you have is an expensive ornament..
"On demand"?? It a 60 year old BSA, you negotiate and reach an agreement. Then it starts ;D
These old bikes have their own needs and it takes a period of usage to get to know these procedures.
And, sadly, as the weather changes the needs change.
Choke on or off
Tickle or not
Tdc or anywhere
Also , if not started for a while, they inevitably will wet sump a bit making it a bit more difficult to rotate the engine
Just go out to the shed and start it and try different things , but the most important is empathy.
If tickling and choke combination don't result in a start , then you've probably flooded it , so choke off , wide open throttle and kick again,
Mine responds well to that
SO many variables! I am thinking of putting together a table of all the things to try so I don't miss any combinations.
just think - you'll get used to 1 way of coaxing it into life then bingo it changes !!
Yes, much depends on the ambient temperature. My Electra needs the air slide plus generous flooding at temperatures in the low teens but the air slide suffices in the 20s.
I also think a lot depends on the idle screw setting. If the idle circuit mixture has been set before the engine is fully warmed up it will be too rich which will allow it to start and run without the slide. If its set correctly on the idle mix its likely to need 1/2 slide for a minute or two to stop it spitting back.
Well, I managed to get it to start eventually this morning. I'll have another go on Friday, when I am at home. But I think it might need the idle and maybe the mixture, tweeking a bit. It stalled after warming up, when I backed off the throttle.
Well done ,
When you next try , get it going and hold the twist grip carefully keeping it going.
Then bring the tickover screw up a bit to allow you to release the twistgrip.
Then , carefully, tweak the air screw in and out to get a steady tickover . This screw is nominally all the way in and 1.5 turns out (but around that is fine , don't get fixated on this)
You should add that the engine needs to be up to working temp before tweaking the mixture etc.
Yep , forgot that , most important bit
Quote from: limeyrob on 31 Aug, 2026, 16:01 I also think a lot depends on the idle screw setting. If the idle circuit mixture has been set before the engine is fully warmed up it will be too rich which will allow it to start and run without the slide. If its set correctly on the idle mix its likely to need 1/2 slide for a minute or two to stop it spitting back.
I can't see that 1/2 slide does anything at idle speeds as the choke slide will be up inside the throttle slide and won't come into operation until half throttle or so. It's a pretty crude device anyway.
Amal used to provide a device on the throttle stop for 276 type carbs to raise the slide slightly for cold starts, but I think was only available on Nortons and Velos. I adapted the idea for the Wassell Evolution on my Electra to allow for it to idle both when cold and warm.
(https://www.iansoady.org.uk/Norton%20Electra/images/throttle%20stop%202.jpg)
You may well be correct. But I've noticed that my RR picks up better and runs cleaner with some slide. Its very cold blooded and takes a while to settle to smooth running. If I blip the throttle it will die without some slide, perhaps the blipping is bringing the slide into the flow.
After the joys of getting the bike started last weekend, it is back to not wanting to know today. I set the mixture screw to 1 1/2 turns and the idle to just lift the slide.
I've tried tweeking all the variables I can think of, including kicking over with switches off to clear flooding.
Lots of kicking. Just the occasional splutter and then back to nothing.
It looks like it is all down to technique. Ray came over this afternoon, and stomped on the starter with his (must be) 14 stones. The bike started right up. I am going to strap on my exercise weight belt. My 10st 8 lbs just isn't cutting it.
I have to agree that there is no definitive method of starting the damned things.
My B44 to my mind was a pig to start. So I have fitted the choke slide that came with the new carburettor.
She's still an awkward bugger!
The one thing I have discovered is to either use the choke or tickle the carb, but don't do both.
It still takes 4 or 5 attempts before she fires up whichever method I use and if she cuts out it takes about 3 attempts to get her going again even though she's well up to temperature.
I've tried a myriad of techniques, but all to no avail.
One thing I have found useful is my old Gunsons Colourtune to get the mixture right at tick over.
Of course all the rest is down to having the correct size jets fitted which can be a nightmare to ascertain as BSA, in the case of the B44 seemed to alter the sizes every year. Even though the engine and carburettor type were identical.
If I can get to the point that I can start my bike in three kicks I will be pretty chuffed.