The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Amal, Carburation, Fuel => Topic started by: Derby Rob on 11.04. 2015 19:12

Title: rich and weak mixture
Post by: Derby Rob on 11.04. 2015 19:12

hi,
   this may seem an odd question.....is it possible to have both rich and weak mixture at the same time ?

Let me explain what i mean,the exhaust headers are a light brown colour ,and if you wipe your finger inside of the tail pipe its  wet and black,not light grey/white.So i was thinking that the mixture was on the rich side,it starts and runs ok but some times spits/misses when pulling away from a stand still when warm.

Reading Amals info on their carbs the spitting back indicates a weak mix.So do i have the air screw set too weak for tick over/low revs ,and my needle too high for normal engine speed ?

I think i will remove the carb and check everything any way ,but just thought i would do a post in case i am missing some thing that may seem obvious to you guys on here .

The bike is a 61 A7 iron head ,and i thought all the carb settings/jets were as the book, but will find out when i take the carb off
    cheers Rob
 

Title: Re: rich and weak mixture
Post by: muskrat on 11.04. 2015 21:06

G'day Rob.
The Amal has four tuning points. Pilot, Slide, Needle and Main. So theoretically you could be rich lean rich lean. Download this amalcarb.co.uk/downloadfiles/amal/amal_tuning_guide.pdf
Cheers

Title: Re: rich and weak mixture
Post by: Derby Rob on 12.04. 2015 00:14

thanks muskrat,will do

Rob