Concentric Carb Issue

Helpful information and requests for assitance and advice
User avatar
spookefoote1956
Member
Posts: 1836
Joined: Mon May 01, 2017 7:32 pm
Location: Wales Innit

Concentric Carb Issue

Post by spookefoote1956 »

I've put the concentric carb back on the Cub as I think the ability to "tickle" has an effect on starting. However if I don't tickle, even when warm, she won't have it. My brain's saying pilot jet blocked or something related to the pilot. Possibly throttle valve needle too low. The other clue is that she's struggling to tick over at low revs, What do your brains think? :? :? :? :?
Hail Joe Lucas ............ Prince of Darkness!
All my bikes are original........ to me!
"Creativity is your intelligence having fun" Albert Einstein
User avatar
dave16mct
Member
Posts: 3234
Joined: Mon Jan 01, 1990 12:00 am
Location: LANCASHIRE UK

Re: Concentric Carb Issue

Post by dave16mct »

Pilot jet blocked.
User avatar
spookefoote1956
Member
Posts: 1836
Joined: Mon May 01, 2017 7:32 pm
Location: Wales Innit

Re: Concentric Carb Issue

Post by spookefoote1956 »

Cheers Dave, nice to hear from you again. I must pop over to club night. :beer:
Hail Joe Lucas ............ Prince of Darkness!
All my bikes are original........ to me!
"Creativity is your intelligence having fun" Albert Einstein
Richard Mills
Member
Posts: 71
Joined: Mon Jan 01, 1996 12:00 am
Location: Doncaster UK

Re: Concentric Carb Issue

Post by Richard Mills »

Fuel level in float chamber too low?
User avatar
spookefoote1956
Member
Posts: 1836
Joined: Mon May 01, 2017 7:32 pm
Location: Wales Innit

Re: Concentric Carb Issue

Post by spookefoote1956 »

I've cleaned out the carb, removed the air screw and given it a blow job with the compressor but it still doesn't want to idle. It may be worth looking at either a MK1 premier concentric or a monobloc. At least then I can alter the pilot jet.
Hail Joe Lucas ............ Prince of Darkness!
All my bikes are original........ to me!
"Creativity is your intelligence having fun" Albert Einstein
bob121
Posts: 291
Joined: Sat Jan 14, 2017 11:48 am
Location: WEST MIDLANDS UK

Re: Concentric Carb Issue

Post by bob121 »

It may be worth running it through an ultrasonic before replacing.
User avatar
spookefoote1956
Member
Posts: 1836
Joined: Mon May 01, 2017 7:32 pm
Location: Wales Innit

Re: Concentric Carb Issue

Post by spookefoote1956 »

Nice one Bob. I'll give it a go.
Hail Joe Lucas ............ Prince of Darkness!
All my bikes are original........ to me!
"Creativity is your intelligence having fun" Albert Einstein
Dave T_LAPSED
Posts: 157
Joined: Tue Mar 29, 2016 7:19 pm
Location: CALVADOS FRANCE

Re: Concentric Carb Issue

Post by Dave T_LAPSED »

Bonjour, greetings from that France! Just a thought, have you checked for a nair leak between carb and cylinder head, abvious I know but worth a check. Carb problems are always frustrating, good luck.
Dave.
Mick D
Posts: 2886
Joined: Mon Mar 24, 2014 5:44 pm
Location: Aberdeenshire

Re: Concentric Carb Issue

Post by Mick D »

spookefoote1956 wrote:she's struggling to tick over at low revs
Hi

That sounds more like the volume control screw, (air screw), needs attention - have you gone through the throttle stop / air screw dance?

Regards Mick
User avatar
spookefoote1956
Member
Posts: 1836
Joined: Mon May 01, 2017 7:32 pm
Location: Wales Innit

Re: Concentric Carb Issue

Post by spookefoote1956 »

A big Saturday bonjour to you too Dave. There is a gasket and rubber "O" ring. I suppose I could remove the gasket and try a bit of goo in there.

Mick could you illuminate a bit more regarding the air-screw please. I have twiddled for performance (Ooer!)
Hail Joe Lucas ............ Prince of Darkness!
All my bikes are original........ to me!
"Creativity is your intelligence having fun" Albert Einstein
Locked