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Discussion Starter #1
As you might have seen from earlier posts, I am having trouble with a brand new set of Amals. Everything points to pilot jets. Here is the rub...
Not sure how far the guitar string should penetrate to insure that I have actually fixed anything.

I measure 1 1/4 inch penetration ..not the 1 1/2 inches I have seen quoted. When looking the bottom of the carb...with the bowl off...I am getting past the round brass piece ..which I think is the mixing chamber...but am not getting to the center of the channel which leads to the little gas port that pulls fuel out of the bowl. Is there a way to test this before putting back on the bike?

Any hints? Also...has anyone ever seen carbs that were un fixable in this regard?

Thanks again
 

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This probably explains it better then I can. http://www.jba.bc.ca/Bushmans Carb Tuning.html

The way to test before installing carbs is to blow through each of the 3 to 4 openings for the pilot circuit with compressed air. Block one or two of the openings with your fingers and check for air coming out the other opening(s). Also you this technique when cleaning.

If you don't have compressed air, you can get by with an aerosol can of carb clean or brake cleaner with a straw on the nozzle.

Once the carb is installed , you check for a working properly jetted pilot circuit by adjusting your mixture screw. You should be able to peak the idle rpm between 1 to 2.5 turns. No response is usually indicative of a blocked pilot.
 

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Discussion Starter #3
i have been using Bushman's webpage as well....i am not close to having an idle. My other post of a few days ago describes symptoms....i just don't know how far the wire should go into the jets before you have gone far enough
 

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I will try and pick up a drill bit tomorrow if I have time and measure. I got a bunch of old concentrics in a milk crate.
Can you blow air through all the passage ways?
A friend had problems with the pilots on a new amal being blocked.
 

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I measure 1 1/4 inch penetration ..
..but am not getting to the center of the channel which leads to the little gas port that pulls fuel out of the bowl. Is there a way to test this before putting back on the bike?
You're not there yet;it's still blocked.I assume these carbs have pressed-in jets behind the idle mix screw,not screw-in jets.
Usually you can push a wire in 1-9/16",after you remove the mixture screw.
You have noticed that the wire doesn't reach to the centre of the channel from the float bowl.It should get there.
It is easier to clear it with a drill bit glued into an extension tube.The drill bit alone is too short to reach.A WD-40 nozzle makes a good enough extension.Use a #78 drill or a 0.4mm drill.

It can be hard to clear with a wire.I've used 0.014" wire from a plastic bag tie,and it takes some persistance.Carb cleaner or WD-40 helps.
When it's clear,you can blow through from the float bowl channel to the pilot screw hole.Try squirting WD-40 through.After that,put the screw in place and it should blow through to the discharge holes near the front bottom edge of the slide.
 

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I just read in your other thread that you were using a 0.017" diameter wire.No surprise that it doesn't fit;luckily.
If you did manage to push that through,the jet would flow 13% more than it should.You have adjustment on the air screw,when the throttle is fully closed on the stops.As you open the throttle,the air screw is less effective and the jet size controls the mixture.

A 0.017" hole in the jet would make things too rich just above idle.
 

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Apparently there were some Amal Concentric carbs made a wee while back that did not have the pilot air way drilled correctly.
If you say they are new and they have never worked right from the start,then probably best thing to do is contact the dealer you bought them from or Burlen (who make Amal carbs)
 

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Discussion Starter #8
update..sort of fixed

I moved on to a # 78 drill....started it up...still ran badly ..but maybe somewhat better. So then I tried the only thing left...which I thought would be a waste of time. I moved the needle clip from top position..all the way to bottom. Vastly improved.....i still haven't had time to adjust idle..so I may still have issues...but actually rideable now.

My 2 stroke experience from back in the day would never have resulted in that much change from needle clip position. May be a while before I get this finally sorted...am about to leave town for a while.

Thanks for all the help.
 

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I think you may need to look elsewhere for the cause of your problem. Having fitted several new sets of Concentrics to Triumphs over the last year I would say it is very unlikely that a pair of new carburettors would malfunction in identical ways on each cylinder unless there is something wrong with the specification, not the carburettors themselves. If after cleaning the pilot jets you still think the carbs are at fault then all new Amals have a 12 month warranty (in the lid of the box) so you can return them to the seller who either fixes or replaces them. You could also contact Amal direct. Do you have the previous set of carburetters. Fitting them may help you decide whether the problem is the carbs, or the ignition, or something else.
 

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Discussion Starter #10
I have the previous carbs...they have very worn slides and bores. When I bought the bike, they seemed to work..but idled way high. Before I could fix the idle..the bike siezed..since the previous owner reversed the oil lines. I am reluctant to put these old carbs back on.

I am going to try and set the idle and see if that works ok...otherwise..good advice on warranty.
 

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Discussion Starter #11
getting closer..but still no cigar

Ok....now runs without chokes on...but won't idle below 2000 rpm. appears carbs are way out of balance...but am pretty sure that the pilot jets/mixture screws are doing something.

So I want to do the 1 cylinder at a time drill...but have one IMPORTANT
question. I have a PAZON ignition....most ( all?) electronic ignitions don't like to not have a path to ground for the spark. Do I have to put the plug lead on a spare plug and strap it to the head so there is a path? Or I guess i could find a spare plug..hammer the gap shut so it has no spark and thread it into the cylinder I want to shut down?
 

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Discussion Starter #12
alternative

Since I have dedicated fuel lines for each carbs...I guess I could just
shut off the gas for one side and drain the bowl. As long as there is no gas..shouldn't have a " lean burn " issue. Any hidden flaws in that logic?
 

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Discussion Starter #13
the end of the story

Here is what I did and here are the results....

1. Did the " one cylinder at a time " drill. Drained the gas from carb..started it up as a single....all of the below is with the chokes
off( raised)

2. Still idled at 2-2500 rpm..required copious tickling to start.

3. So I bottomed out the air screw on the live cylinder's carb..lowered the idle screw til the engine was running at about 2000 rpm...and
sounding like it might quit....

4. Then I started to open the air screw....at 1/2 turn open..engine quit dead.

5. The other cylinder was so erratic I couldn't tell what was happening.


So my conclusion is that my pilot circuit is not doing much and I am running off the needle circuit..hence high idle. That may explain why moving clip made it run better? Thoughts?
 
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