The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: bill harrison on 01.06. 2016 09:40

Title: Uneven running at very light throttle openings
Post by: bill harrison on 01.06. 2016 09:40

One of my A10's, a 1958 Super Rocket runs very well although I suspect runs a little rich as you can get rid of the choke straight after start up.  It also has an unpleasant on off feeling at light throttle.  None of my other bikes does this and I suspect that the mixture may be rich and as you lift the slide it suddenly picks up.  Can I fix this by adjusting the idle mixture?
Thanks.

Title: Re: Uneven running at very light throttle openings
Post by: Klaus on 01.06. 2016 10:48

hi bill,

have a look at your airscrew, this is important for ticking over.
After lifting the throttle the cutaway does the venturi and needle position is in action.
A worn needlejet is caused if the bike run very rich if needle is in right position.

cheers Klaus

Title: Re: Uneven running at very light throttle openings
Post by: bill harrison on 01.06. 2016 10:56

OK, I think it needs to screw out a bit to weaken the mixture at tickover.

Title: Re: Uneven running at very light throttle openings
Post by: muskrat on 01.06. 2016 21:08

G'day Bill.
Once you get the air/pilot screw right for a nice idle it can then be adjusted about 1/8th turn either way to get a good lift. May have to reset idle screw again.
Cheers

Title: Re: Uneven running at very light throttle openings
Post by: bill harrison on 02.06. 2016 08:30

OK, its shocking weather here I'll have to wait until I can get out!  I changed the voltage regulator yesterday for one of the new solid state ones but seems still not to be charging.  Looks like I'll have to make a day of it!

Title: Re: Uneven running at very light throttle openings
Post by: Triton Thrasher on 02.06. 2016 15:37

Buy a new needle jet from Amal, unless you already have.