View or Hide Header -->
Welcome,
Guest
. Please
login
or
register
.
1 Hour
1 Day
1 Week
1 Month
Forever
Login with username, password and session length
This topic
This board
A7 & A10 Engine
A7 1946-1950
Gearbox, Clutch, Primary
Frame
Lucas, Ignition, Charging, Electrical
Amal, Carburation
Entire forum
Google
Home
Help
Search
Contact
Login
Register
The BSA A7-A10 Forum
»
Technical (Descriptive Topic Titles - Stay on Topic)
»
A7 & A10 Engine
»
Jet on Amal 389 to BSA Golden Flash
« previous
next »
Print
Pages: [
1
]
Go Down
Author
Topic: Jet on Amal 389 to BSA Golden Flash (Read 557 times)
GFlash
Moving Up
Join Date: Jul 2011
Posts: 25
Karma: 0
Jet on Amal 389 to BSA Golden Flash
«
on:
19.05. 2018 15:45 »
Hi
Has a Golden Flash from 1954 with 357 cam and open silencer.
Has mounted an Amal 389, which sizes of main jet, needle jet and pilot jet should be appropriate?
Regards
Robert
Logged
RogerSB
1960 Golden Flash, Plymouth, Devon, England
Resident Legend
Join Date: Aug 2017
Posts: 856
Karma: 9
Re: Jet on Amal 389 to BSA Golden Flash
«
Reply #1 on:
19.05. 2018 17:36 »
Hi Robert,
As far as I know 1950 - 54 GF originally had an Amal Monobloc 276.
My 1960 GF has a 389 with 1 1/8" choke, 250 main jet, 30 pilot jet, 3 1/2" throttle slide, 0.106 Needle jet, No3 (from top) needle position.
Logged
1960 Golden Flash
muskrat
Global Moderator
Wise & Enlightened
Join Date: Jul 2009
Posts: 10779
Karma: 130
Lithgow NSW Oz
Re: Jet on Amal 389 to BSA Golden Flash
«
Reply #2 on:
19.05. 2018 21:53 »
G'day Robert.
You don't say what size 389 you have or air filter.
With a straight through pipe and 357 cam and a choke size of 1 1/8" I'd start with a 300 main, the rest as per Rogers settings or just a tad richer and go from there.
Cheers
Logged
'51 A7 plunger, '57 A7SS racer now a A10CR, '78 XT500, '83 CB1100F, 88 HD FXST, 2000 CBR929RR ex Honda Australia Superbike .
Australia
Muskys Plunger A7
GFlash
Moving Up
Join Date: Jul 2011
Posts: 25
Karma: 0
Re: Jet on Amal 389 to BSA Golden Flash
«
Reply #3 on:
22.05. 2018 21:13 »
Thanks for reply.
I have air filter.
Measured and saw that the carburettor is 1 1/8" and the intake is 1 1/16" understand that it is not good?
Regards
Robert
Logged
muskrat
Global Moderator
Wise & Enlightened
Join Date: Jul 2009
Posts: 10779
Karma: 130
Lithgow NSW Oz
Re: Jet on Amal 389 to BSA Golden Flash
«
Reply #4 on:
22.05. 2018 21:27 »
G'day Robert.
A step like that 1/32" isn't great but it's not too bad. you could use a thick insulating gasket to blend the two together.
http://amalcarb.co.uk/phenolic-spacer-26mm.html
Cheers
Logged
'51 A7 plunger, '57 A7SS racer now a A10CR, '78 XT500, '83 CB1100F, 88 HD FXST, 2000 CBR929RR ex Honda Australia Superbike .
Australia
Muskys Plunger A7
Scott and Jay
A's Good Friend
Join Date: Mar 2016
Posts: 94
Karma: 0
Re: Jet on Amal 389 to BSA Golden Flash
«
Reply #5 on:
22.05. 2018 21:34 »
Yes, the bore on the intake manifold needs to be increased to 1 1/6 and matched to the carb - if you want to keep that carb. I got a new Premier Amal 389 carb for my 1958 Golden Flash. It as 1 5/32 bore. I got the intake bored out to match this. With an air cleaner but not-too -restrictive Emgo universal mufflers - I had to go up to a 310 main jet. It runs really nicely at that.
Logged
New Zealand
Print
Pages: [
1
]
Go Up
« previous
next »
The BSA A7-A10 Forum
»
Technical (Descriptive Topic Titles - Stay on Topic)
»
A7 & A10 Engine
»
Jet on Amal 389 to BSA Golden Flash