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- Oct 16, 2016
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Hi, new here, first post.
Amal set up - an easy way.
First thing is bike should be in good order. Ignition, valves set, no manifold or other air leaks, a clean air filter, carbs internals cleaned with unworn jets and throttle cables cleaned and oiled. The float heights should be set, I scribe a mark 2mm down in the float as a target. There is a lot of information on the web about Amals. If the provenance of your carb internals is not known change out internals, especially the needle jet as this wears the most. That's the hard part over.
Assuming all the above is done then in my humble opinion the easiest way of setting up a pair of Amals is as follows.
1. Take the carb caps off, pull the slides out. Lay the slides, springs, cap and needle assembly side by side in palm of your hand. Gently twist throttle, by doing this you should see and feel if they move at the same time. Adjust as required. Then open throttle all the way, both slides should compress the spring and stop moving (at the same time) when almost touching the carb cap. It should be apparent by visual and tactile inspection if something is out of sorts. Do all of this with assembly laid across palm of hand.
2. Dismantle one of the slide assemblies. Drop the slide into each carb in turn, adjust idle screw so that it is just touching the slide, (probably going to have to start by turning it out first). By keeping a finger on top of the slide and pushing down gently you will feel when this happens. Retrieve the slide and reassemble.
3. Assemble carbs, take care not to over tighten cap screws as this will cause the slides to stick due to distortion (this applies to all 6 fasteners on each carb, use a spring washer!). Make sure when assembled slides "snap" back from full throttle open. Check this with tank on prior to bolting tank down.
4. Pilot air screw, turn clockwise all the way, gentle seat, then turn back out 1.5 turns. Idle screws (which should have remained untouched) turn clockwise in 1.25 turns, raising the slides equally.
5. Take bike for a short run with a screw driver to hand. When warm set idle by carefully adjusting equally the idle adjust screws.
A) Set on the high side 1200 rpm thereabouts (idle screws). Adjust the pilot air screws in turn, for highest idle speed.
B) Adjust the idle screws (equally) for idle speed of 1000rpm thereabouts. Adjust pilot air screws for highest idle, then turn clockwise (richer) about 1/8th turn.
C) Adjust idle screws for idle of about 800rpm, higher if your preference. It is important not to lose track of where you are at especially with the idle screws, always adjust these both at the same time equally as you are moving the throttle slides and you want to maintain balance.
6. If you have a manometer, attach to the carbs and they should show as pretty well balanced. But at any rate can be used to fine tune.
Norton Commando Combat, 932 carbs, stay up floats, aluminium float valves, 106 needle jet, 230 main, flat top spray tube, no. 3 hard alloy slide, 2 ring needle set at mid position. No choke used, I may get round to chamfered spray tubes and 4 ring needles as an experiment. I tried 4 ring with the flat top spray tubes, kept stalling off idle when engine cold, (lean due to longer needle I think), though got a nice colour on the plugs and ran pretty good when hot. Ridden along the highways and byeways of merry Olde England. I get 57 miles to one of Her Majesty's gallons.
Hope I wasn't trying to teach grandmother to suck eggs, I just haven't seen this methodology (1 & 2, the other stuff is standard practice) described in quite a few hours of Googling although I am sure it's been done before.
Amal set up - an easy way.
First thing is bike should be in good order. Ignition, valves set, no manifold or other air leaks, a clean air filter, carbs internals cleaned with unworn jets and throttle cables cleaned and oiled. The float heights should be set, I scribe a mark 2mm down in the float as a target. There is a lot of information on the web about Amals. If the provenance of your carb internals is not known change out internals, especially the needle jet as this wears the most. That's the hard part over.
Assuming all the above is done then in my humble opinion the easiest way of setting up a pair of Amals is as follows.
1. Take the carb caps off, pull the slides out. Lay the slides, springs, cap and needle assembly side by side in palm of your hand. Gently twist throttle, by doing this you should see and feel if they move at the same time. Adjust as required. Then open throttle all the way, both slides should compress the spring and stop moving (at the same time) when almost touching the carb cap. It should be apparent by visual and tactile inspection if something is out of sorts. Do all of this with assembly laid across palm of hand.
2. Dismantle one of the slide assemblies. Drop the slide into each carb in turn, adjust idle screw so that it is just touching the slide, (probably going to have to start by turning it out first). By keeping a finger on top of the slide and pushing down gently you will feel when this happens. Retrieve the slide and reassemble.
3. Assemble carbs, take care not to over tighten cap screws as this will cause the slides to stick due to distortion (this applies to all 6 fasteners on each carb, use a spring washer!). Make sure when assembled slides "snap" back from full throttle open. Check this with tank on prior to bolting tank down.
4. Pilot air screw, turn clockwise all the way, gentle seat, then turn back out 1.5 turns. Idle screws (which should have remained untouched) turn clockwise in 1.25 turns, raising the slides equally.
5. Take bike for a short run with a screw driver to hand. When warm set idle by carefully adjusting equally the idle adjust screws.
A) Set on the high side 1200 rpm thereabouts (idle screws). Adjust the pilot air screws in turn, for highest idle speed.
B) Adjust the idle screws (equally) for idle speed of 1000rpm thereabouts. Adjust pilot air screws for highest idle, then turn clockwise (richer) about 1/8th turn.
C) Adjust idle screws for idle of about 800rpm, higher if your preference. It is important not to lose track of where you are at especially with the idle screws, always adjust these both at the same time equally as you are moving the throttle slides and you want to maintain balance.
6. If you have a manometer, attach to the carbs and they should show as pretty well balanced. But at any rate can be used to fine tune.
Norton Commando Combat, 932 carbs, stay up floats, aluminium float valves, 106 needle jet, 230 main, flat top spray tube, no. 3 hard alloy slide, 2 ring needle set at mid position. No choke used, I may get round to chamfered spray tubes and 4 ring needles as an experiment. I tried 4 ring with the flat top spray tubes, kept stalling off idle when engine cold, (lean due to longer needle I think), though got a nice colour on the plugs and ran pretty good when hot. Ridden along the highways and byeways of merry Olde England. I get 57 miles to one of Her Majesty's gallons.
Hope I wasn't trying to teach grandmother to suck eggs, I just haven't seen this methodology (1 & 2, the other stuff is standard practice) described in quite a few hours of Googling although I am sure it's been done before.