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Motorcycle Discussions => British Bikes => Topic started by: BSABOB on March 25, 2010, 08:31:12 AM

Title: BSA B31 Carb Problem - Please Help!!
Post by: BSABOB on March 25, 2010, 08:31:12 AM

Does anyone know why I have to put my hand over the carb to start the engine, it has a concentric carb with no leaks on either manifold?

Title: Re: BSA B31 Carb Problem - Please Help!!
Post by: davet147 on March 25, 2010, 08:46:44 AM

Hi

I have attached a link for you to look at, hope it helps.

http://www.amr-of-tucson.com/carb_facts.html

Dave.

Title: Re: BSA B31 Carb Problem - Please Help!!
Post by: Searchguru on March 25, 2010, 09:30:03 AM

BSABOB,
Your hand is acting like a 'choke' effectively reducing the amount of air so increasing the ratio of fuel to air that is drawn into the engine. Has this recently been required or has it been needed for a long time? This could be down to wear and/or incorrect adjustments. I haven't 'fiddled' with any Amal carbs for 30 years but has yours got a 'tickling' button to push the float down inside the carb. I remember having to tickle my bonnie to get the fuel flowing and it started a treat. My duke, however, just had accelerator pumps that squirted fuel in if you twisted the throttle either method increased the fuel as neither bike had chokes fitted.