1968 Commando: left cylinder does not start (2016)
- Thread starter pierodn
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All well what ends well.
As far as i know the 1968 Commando fits the 930 Amal 27/28, like my 1967 Atlas that has 180 main jets and cut 2 sliders.
I found this 27/28 carbs on the Commando tuned with 240 main jets, 106 needle jets, cut 3 slides and jets needle 2 grooves.
The right n. 930/27 carbs has always worked fine.
Not the left.
I changed this carbs twice with two other old 930/27.
I wanted to keep the most rigorous originality of the bike.
I thought this carbs could work fine.
But i was in wrong.
To day i have changed both the carbs with two 930/68/69 that come from a my 1971 running Commando, tuned like per manual.
The bike started at the first kick and was running great but, sorry, doesnt longer have the original carbs!.
At the end of this history i know that when you think that a carb is well cleaned, also when the air/fuel circuit are opened, it could be garbage.
So i can say that a carburetor works fine only when the bike runs well.
But now i have two good carbs less.
Ciao
Piero
As far as i know the 1968 Commando fits the 930 Amal 27/28, like my 1967 Atlas that has 180 main jets and cut 2 sliders.
I found this 27/28 carbs on the Commando tuned with 240 main jets, 106 needle jets, cut 3 slides and jets needle 2 grooves.
The right n. 930/27 carbs has always worked fine.
Not the left.
I changed this carbs twice with two other old 930/27.
I wanted to keep the most rigorous originality of the bike.
I thought this carbs could work fine.
But i was in wrong.
To day i have changed both the carbs with two 930/68/69 that come from a my 1971 running Commando, tuned like per manual.
The bike started at the first kick and was running great but, sorry, doesnt longer have the original carbs!.
At the end of this history i know that when you think that a carb is well cleaned, also when the air/fuel circuit are opened, it could be garbage.
So i can say that a carburetor works fine only when the bike runs well.
But now i have two good carbs less.
Ciao
Piero
texasSlick
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Piero wrote:
"Now i can say that a carburetor works fine only when the bike runs well.
But now i have two good carbs less."
Glad you solved the problem.
Your two not good carbs can be made well. Completely dis-assemble, clean all ports, use a wire if necessary (damn those who say never use a wire), replace parts as required. There are several good "how to" links. PM if you need one.
Slick
"Now i can say that a carburetor works fine only when the bike runs well.
But now i have two good carbs less."
Glad you solved the problem.
Your two not good carbs can be made well. Completely dis-assemble, clean all ports, use a wire if necessary (damn those who say never use a wire), replace parts as required. There are several good "how to" links. PM if you need one.
Slick
o0norton0o
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Congradulations, Piero. Here's a good link about amals. I found this info to be very helpful, and as I said previously, when I couldn't get one cylinder to idle correctly, I drilled out the back of the carb to inspect the jet, as per the instructions on the website and fixed my bad carb. Maybe you can fix one of your bad one's too.
http://www.jba.bc.ca/Bushmans Carb Tuning.html
http://www.jba.bc.ca/Bushmans Carb Tuning.html
o0norton0o said:
Hi.
I know the Bushmans tuning.
I mean and do it every time i use a carb.
As you can read in my previous replay, i did it, drilled out the back of the carb and cleaned again.
But without any good result.
Even if the circuits are very well cleaned, and air and fuel split out fine, the carbs do not work the same.
Ciao
Piero
texasSlick said:
Hi.
I did it like Bushmans says without results.
This just happened with my right BSA A65 L cylinder.
I never bought new Amal, always use the original carbs of the year.
I have had problems only two time, with BSA and with this 68 Commando.
May be is better to throw this carbs.
Ciao
Pieto
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- Dec 3, 2009
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Not sure what Hobot used, but I've boiled plugged up carbs in soapy water in the past.
Disassemble the Carb as much as possible and place everything in a pot of soapy water. Heat to boiling ( I use a camping stove) and keep up the boil for a few minutes while using tongs to roll the Carb around in the boiling water. Pull the Carb out with the tongs and immediately hit it with compressed air, especially in the small passageways. It will dry almost instantly.
This has always worked well for me.
Use any regular liquid dishsoap that is on hand.
Glen
Disassemble the Carb as much as possible and place everything in a pot of soapy water. Heat to boiling ( I use a camping stove) and keep up the boil for a few minutes while using tongs to roll the Carb around in the boiling water. Pull the Carb out with the tongs and immediately hit it with compressed air, especially in the small passageways. It will dry almost instantly.
This has always worked well for me.
Use any regular liquid dishsoap that is on hand.
Glen
texasSlick
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After following this thread to completion, I am of the opinion that Bob Z may have identified Piero's problem. The cylinder would not fire, NOT due to a blocked idle circuit failing to deliver fuel, but rather due to too much fuel caused by an oversized pilot jet, or a missing jet.
This would explain Piero's insistence that he had cleaned the pilot circuits adequately, and also explain why the cylinder fired after he screwed out the air screw entirely, leaning out the mixture to where it would fire.
If this is the case, then Piero needs only check the pilot jet for size and proper installation.
Slick
This would explain Piero's insistence that he had cleaned the pilot circuits adequately, and also explain why the cylinder fired after he screwed out the air screw entirely, leaning out the mixture to where it would fire.
If this is the case, then Piero needs only check the pilot jet for size and proper installation.
Slick
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