A carb question

Yellow_Cad · Dec 28, 2010

I'm trying to nut out a hot cylinder with Boyer ignition. I have twin Amals. An older post suggests among other steps to check for a lean condition by "Check that gently depressing the float after fill/shut-off causes the bowl to refill further to overflowing." I'm not sure how to do this but it seems that the tickler does just that.

Another question: could a stuck tickler (overly rich situation) cause hotter (blue or more) exhaust on one side? because I have had a stuck tickler on that side before.

Hobot · Dec 28, 2010

You can't test the tickler pressing to enrich mixture unless you are running along in the trouble range of operation. Pushing tickler raise fuel level which then can spill out-suck out more fuel out the spray tube.

Over rich mixtures are famous for dimming the fire to cooler sooty condition.
Lean is famous for hot enough to blue stain chrome.
Most likely cause most famous of all in Amal and other carbs, Pilot Jet Clog.
2nd would be ign timing, but same each side with wasted spark systems.
3rd might me air leaks at carb or exhaust side.

snibor · Dec 28, 2010

hobot said:
You can't test the tickler pressing to enrich mixture unless you are running along in the trouble range of operation. Pushing tickler raise fuel level which then can spill out-suck out more fuel out the spray tube.

Over rich mixtures are famous for dimming the fire to cooler sooty condition.
Lean is famous for hot enough to blue stain chrome.
Most likely cause most famous of all in Amal and other carbs, Pilot Jet Clog.
2nd would be ign timing, but same each side with wasted spark systems.
3rd might me air leaks at carb or exhaust side.

and of course make sure the needle clips are set on the same grove .... and if in fact the correct needles are installed

steve

cash · Dec 29, 2010

I would think a safe way to check for lean running would be to slowly drop the choke slides while riding in the problem area. I'm sure this method was mentioned in Amal fault finding instructions.

Cash

Yellow_Cad · Jan 25, 2011

hobot said:
You can't test the tickler pressing to enrich mixture unless you are running along in the trouble range of operation. Pushing tickler raise fuel level which then can spill out-suck out more fuel out the spray tube.

Over rich mixtures are famous for dimming the fire to cooler sooty condition.
Lean is famous for hot enough to blue stain chrome.
Most likely cause most famous of all in Amal and other carbs, Pilot Jet Clog.
2nd would be ign timing, but same each side with wasted spark systems.
3rd might me air leaks at carb or exhaust side.

Just to be sure on the pilot jet cleaning. I'm going in 1 1/2 inches with .016 inch wire and when I blow it with air nozzle I hear air. Should be clean shouldn't it?

pete.v · Jan 25, 2011

Yellow_Cad said:
Just to be sure on the pilot jet cleaning. I'm going in 1 1/2 inches with .016 inch wire and when I blow it with air nozzle I hear air. Should be clean shouldn't it?

You want to feel air coming from this hole outlined in marker, just inside the slide seating. Also put the air screw in just past the oring and blow in the hole marked in the second photo and you feel air at the little hole also. This should complete the pilot circuit. If you turn the air screw all the way in, no air should be coming through.

rvich · Jan 25, 2011

The frustrating thing is that if you work on enough stuff you will probably fix the problem and never be sure exactly which items cured it. Check the following link for pilot circuit info:

amal-carb-pilot-circuit-t8029.html?hilit=%20amal

When I first got my 750 running I turned the pipes cherry red...the one on the right more so than the left. By the time I was done the Amals had been rebuilt and a Tri Spark installed. The timing marks were also verified with a degree wheel. The exact cause of my overheating is only a guess, but it isn't doing it anymore!

Russ

Jeandr · Jan 25, 2011

rvich said:
The frustrating thing is that if you work on enough stuff you will probably fix the problem and never be sure exactly which items cured it. Check the following link for pilot circuit info:

amal-carb-pilot-circuit-t8029.html?hilit=%20amal

When I first got my 750 running I turned the pipes cherry red...the one on the right more so than the left. By the time I was done the Amals had been rebuilt and a Tri Spark installed. The timing marks were also verified with a degree wheel. The exact cause of my overheating is only a guess, but it isn't doing it anymore!

Russ

Most Norton are haunted, you must have displeased it in some ways. The only cure that I know of is to give it some care, take things off, clean them and then put them back on, fiddle with ignition timing, turn air and idles screws a bit one way, then the other way, after that it should be OK :roll:

Jean

lynxnsu · Jan 26, 2011

just to say that this shows the cut-away spray tubes , intended foe that infamous black box airfilter .
it was actually for stinckwheels (also known as 2strokes)intended
if you run something else as airfilter you must fit the full spraytubes or the engine can do all sorts of unexplainable symptoms or react weird to tuning

pvisserij sorry to pick your pic wthout the quote-modus but as you know i am useless with a pc

Yvesnorton je hebt er iets prachtig van gemaakt we moeten eens gaan rijden en vergelijken....

pete.v · Jan 26, 2011

pvisseriii said:
Yellow_Cad said:

Just to be sure on the pilot jet cleaning. I'm going in 1 1/2 inches with .016 inch wire and when I blow it with air nozzle I hear air. Should be clean shouldn't it?

Click to expand...

You want to feel air coming from this hole outlined in marker, just inside the slide seating. Also put the air screw in just past the oring and blow in the hole marked in the second photo and you feel air at the little hole also. This should complete the pilot circuit. If you turn the air screw all the way in, no air should be coming through.

I failed to mention that there is a pilot circuit orifice on both side of the slide seating just in front of the one marked.

Captain B · Jan 26, 2011

lynxnsu said:
just to say that this shows the cut-away spray tubes , intended foe that infamous black box airfilter .
it was actually for stinckwheels (also known as 2strokes)intended
if you run something else as airfilter you must fit the full spraytubes or the engine can do all sorts of unexplainable symptoms or react weird to tuning

pvisserij sorry to pick your pic wthout the quote-modus but as you know i am useless with a pc

Yvesnorton je hebt er iets prachtig van gemaakt we moeten eens gaan rijden en vergelijken....

WHOA!!! Hold on. I've never heard of this! You mean that since I removed the black box and went to a reusable/high flow air filter, that I should replace the spray tubes with full ones (not cut away)??? I'm very interested on hearing about this. Sorry to divert attention from the main topic. I'm very excited to hear that there may be something to help my tuning woes!

pete.v · Jan 26, 2011

Captain B said:
lynxnsu said:

just to say that this shows the cut-away spray tubes , intended foe that infamous black box airfilter .
it was actually for stinkwheels (also known as 2strokes)intended
if you run something else as airfilter you must fit the full spraytubes or the engine can do all sorts of unexplainable symptoms or react weird to tuning

pvisserij sorry to pick your pic without the quote-modus but as you know i am useless with a pc

Yvesnorton je hebt er iets prachtig van gemaakt we moeten eens gaan rijden en vergelijken....

Click to expand...

WHOA!!! Hold on. I've never heard of this! You mean that since I removed the black box and went to a reusable/high flow air filter, that I should replace the spray tubes with full ones (not cut away)??? I'm very interested on hearing about this. Sorry to divert attention from the main topic. I'm very excited to hear that there may be something to help my tuning woes!

After speaking with AMAL, they also suggest needle 622/124. 2 groove identifier.
Here is their response;

Dear Mr xxxxx,

The standard four stroke spray tube for a Mark 1 carburetter is 622/074. They cost £1.68. You should also change to the stock 622/124 four stroke needle with two scribed lines around the top if you are also still using the 928/104 needle which has four scribed lines.

This article helps identify Mark 1 parts: http://www.amalcarb.co.uk/TechnicalDetail.aspx?id=11

Kind regards,

Phil Beresford
Technical Sales Co-ordinator

A carb question

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