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 Slow and smooth with Amal twin carbs??
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Obio

USA
12 Posts

Posted - 06/18/2006 :  17:19:07  Show Profile  Reply with Quote
Ringed my "new" '72 Daytona and compression is great, over 150psi on both sides. However, she now doesn't want to idle and in fact runs rough until it winds up a bit, then she runs great. Also, the air screws' best position appears to be all the way in on both carbs. Any clues?

Ed

JubeePrince

USA
848 Posts

Posted - 06/19/2006 :  08:24:01  Show Profile  Reply with Quote
Air screws all the way in is over-rich condition...should start with mixture screws at 1 -1/2 turns out.....check that there are no air leaks around intake manifold.....(carb cleaner sprayed on manifold....if engine doesn't rev, no leaks) if you can't affect any change in running with the mixture screws, your pilot jets could be blocked.......clean with a #78 drill bit (.016") (assuming you have the fixed pilot jet). Make sure balance tube between carbs is solid/no leaks.

If it runs well when wound up, this would indicate to me a problem with your pilot jet, as after 1/8 - 1/4 throttle the fuel is handled by the needle and main jet.....

Of course, this is assuming that your battery is good (has and holds a charge), plugs are clean and gapped properly, valves are adjusted and your timing is dead-on........dialing in carbs should be the last thing on the list......

HTH,

Steve Prince


'77 T140J
That's not vibration......that's character!
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Obio

USA
12 Posts

Posted - 06/21/2006 :  05:22:25  Show Profile  Reply with Quote
Exactly my thinking Steve but the interesting thing about these carbs is that there are no visible pilot jets. Diagrams I have show removeable pilot jets but there are none to be found here. I am perplexed.

Ed
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JubeePrince

USA
848 Posts

Posted - 06/21/2006 :  16:07:48  Show Profile  Reply with Quote
If you have the pressed-in bush type, you should be able to remove mixture screw and shine a bright light up the hole......you should be able to see the brass and the pilot hole....

HTH,

Steve Prince


'77 T140J
That's not vibration......that's character!
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Obio

USA
12 Posts

Posted - 06/24/2006 :  22:21:58  Show Profile  Reply with Quote
Right you are Steve, I can see brass up the mixture jet screw hole. I suspect the jet is plugged. Know of any good ways to clear the pilot jet, preferably without removing the carb?

Ed
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JubeePrince

USA
848 Posts

Posted - 06/25/2006 :  09:50:10  Show Profile  Reply with Quote
Ed -

Its an easy procedure.....I would recommend removing the float bowls and the top-end/slides on carbs...as after you offer up the drill bit to the pilot jet, you'll need to flush well with some spray carb cleaner.....

Get a #78 drill bit (.016").......some people will use a torch tip cleaner, or a piece of cable wire......not a good idea, IMHO, because an undersized jet, or worse, an oversized jet is as useless as a clogged jet.

.016" is the correct size for this jet and will give you the idle you're looking for (provided evrything else is in working order, but we are taliking about Triumphs here...)

I glue/epoxy the drill bit to the end of one of those red carb cleaner spray tubes.....just be sure it's attached well, as you don't want that bit geting stuck in the jet...

I believe it's about 2.5 - 3" in to the jet thru the air mixture hole.....just gently twist/push the bit in until it bottoms out....then spray lots of carb cleaner throught the jet and the air intake port at the mouth of the carb to wash out any swarf....the removal of the float bowls ensures none of this junk finds its way into the main jet or float needle....also a good idea to spray cleaner through the mixing chamber hole......you can access this by removing the top end of the carbs and the slides to expose these circuits......

Pic of drill bit (courtesy of John Healy):



Email me off-line and I can give you a great Amal link.....

HTH,

Steve Prince


'77 T140J
That's not vibration......that's character!
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Obio

USA
12 Posts

Posted - 07/04/2006 :  17:39:13  Show Profile  Reply with Quote
Steve,

I sort of followed yopur advice but cheated a bit. Couldn't easily find a #78 bit so I took some steel wire and gently probed the jets. Then I flushed them both with carb cleaner while cold. One came around and the other didn't. I pulled the air screw on the recalcitrant carb, fired up the bike and pumped carb cleaner straight into the jet. Worked like a charm. She idles like a triumph should.

Thanks

Ed
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Grumpy

New Zealand
542 Posts

Posted - 07/04/2006 :  22:19:37  Show Profile  Visit Grumpy's Homepage  Reply with Quote
Ha, idles like a Triumph should, misses, farts, etc.

Seriously well don.

Cheers,
Trev
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JubeePrince

USA
848 Posts

Posted - 07/09/2006 :  23:34:39  Show Profile  Reply with Quote
Good for you Ed.....those #78 bits can be found at any industrial tool supply (not Home Depot or Lowes). I purchased mine through W. W. Grainger......one of the best tools in my kit!! Glad to hear the cable worked, but remember, a wrong sized pilot jet is just as bad as a clogged one!!


Cheers,

Steve Prince



'77 T140J
That's not vibration......that's character!
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peterk

United Kingdom
92 Posts

Posted - 12/06/2006 :  04:49:18  Show Profile  Reply with Quote
An ideal tool for cleaning carb pilot jet is a .016 guitar string. I tried a 'G' from a set of Ernie Ball super slinky...works a treat!

Pete
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Push Rod

USA
120 Posts

Posted - 12/07/2006 :  10:42:17  Show Profile  Reply with Quote
The guitar string has been my weapon of choice for cleaning out amal pilot jets for years. I like the "tool" aspect of the small drill and spray tube! I might have to make one.

-1967 T 100 C-
Some people call it a Kaiser blade. I call it a sling blade, mmmmhhhh.
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rwarner

USA
365 Posts

Posted - 12/22/2006 :  22:37:09  Show Profile  Reply with Quote

Hello All;
pete

quote:
Originally posted by peterk

An ideal tool for cleaning carb pilot jet is a .016 guitar string. I tried a 'G' from a set of Ernie Ball super slinky...works a treat!

Pete


That's what I used.
I think that would put the "E" string at .008. Do you play?

Bob
'68 T120R
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peterk

United Kingdom
92 Posts

Posted - 01/02/2007 :  11:58:29  Show Profile  Reply with Quote
Hi Bob,

Close! .009 .....I find .008's a wee bit thin. Yes I do (still) play. Just local gigs for fun these days- rockin blues using strat + vox AC30 with Les Paul for slide.

Cheers

Pete
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