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#891008 09/18/22 9:15 am
Joined: Sep 2022
Posts: 1
S
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S
Joined: Sep 2022
Posts: 1
I cant get my A65L to run properly it idles and runs very roughly:
Jetting of my 1968 bsa A65L, with 930 AMAL Concentric,
according to several books:
Main jet: 190
Choke: 2½
Needle: 2 groves (2stroke)
Needle pos: 2
Jetholder: 2stroke
Pilot jet: 20
Needle jet: 106
In 1969 AMAL changes over to 4 stroke jet setting : Needle with 3 grooves, taller jet holder, pilot jet fixed pressed into carb. body: size 20
https://www.classicbritishspares.com/.../updated-amal ...
How have you been jetting your bsa 65 wit 2 x AMAL carb with the above changes?
how have you jetted your A65 Lightning with AMAL Concentric? spitfire ?
Right now my a65 with 2 x newer 32 mm Concentric is jetted as a 1967 spitfire( but converted to 4stroke specs):
Main jet 190
choke: 3
Needle: grooves (4 stroke)
Needle pos: 2
Jetholder: 4stroke
Pilot jet: 20(pressed into carb body)
Needle jet: 107
Best regards
Søren N
Denmark

Last edited by Søren N; 09/18/22 10:02 am.

Søren
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Any carbs I sell, I advise using the 69 and later jetting on a standard bike. I did as you did when I first got mine on the road and found it to be too rich. Isent my carbs back to Burlen to have the bush fitted (now I got premier carbs which means the bush isn’t needed)

Following this I made a few changes to the bike but it was a pretty stock 68 Lightning.

My own bike now prefers a 105 needle jet and bigger main jet. This is using 928 with early small port head

Depending on if I have my 2-1 with Dunstall mega or twin pipes denotes what need I have fitted (standard 2 ring for twin - standard exhausts. And 5 ring needle for the mega)

Either way I have a 3 ring pilot jet.
3.5 slide
105 needle jet
Needle type as per above, either way they are on the leanest setting (pos 1)
230 main jet.

Not sure why it prefers the 105 needle jet, can only assume it is down to the fuel or my setup. It also has an X12 mega cycle road race cam


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (now rebuilt)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)

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If your carbs are 32 mm , "Right now my a65 with 2 x newer 32 mm Concentric is jetted as a 1967 spitfire", then 190 MJs are too small, try 220s.


71 Devimead, John Hill, John Holmes A65 750
56 Norbsa 68 Longstroke A65
Cagiva Raptor 650
MZ TS 250
The poster formerly known as Pod
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My '68 spitfire settings with 932 premier carbs, 4-stroke configuration (stock exhaust):

Pilot jet: #19
Needle jet: 106
Main jet: 250
Slide: 2.5 (could probably use a 2)
Needle clip: bottom groove (fully raised)

At this point it starts well using the choke and runs perfectly without choke once warmed up.

You don't mention at what point the bike struggles. Based on the description above, I would make sure that all passages are cleared and new jets installed. Sounds like you replaced the 930s with newer 932s; did that make any differences?


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