Amal Retentive

swooshdave · Jan 31, 2010

It's time to start diving into the carbs. I have a brand new set, unfortunately the are for my Triumph project and they are only 930s. Not to fear the box o' Amals are here!

In this pile we find a nice set of 932s. It's the ones in the center, bowls, tops and manifolds.

I really want to try the screw-in pilot jets. I detest the thought of the pilot jet being so buried in the carb body. If I recall, the 4 stroke Amals had the screw-in pilot up until the late 60s. So there is no reason they wouldn't work. Right? I like the screw-in pilots on my 'Tacos. If they get clogged, off they come and so easy to clean.

I have to do more research but I believe you drill out the old jets, plug the hole on the other side and screw in the new ones. Has anyone done this?

JAYMAC · Jan 31, 2010

Hi Dave, there are a few old posts on here about this but you can get some useful info at http://www.jba.bc.ca/Bushmanss%20Carb%20Tuning.html
Cheers John Mc

byrdman76 · Jan 31, 2010

On my 930's I drilled the plug out on mine out with 13/64 drill bit and cleaned the pilot and passages - I did not try and remove the jet. This seems to me as the only way to ensure that the jet and passages on both sides of the jet are truly clean. If not it will just force the debris possibly into the passage on the other side of the jet and "hopefully" come out. I then used a bottom 1/4-20 tap to tap the new whole that I drilled, and then sealed the hole up with a self sealing 1/4-20 set screw. I have not tested this for leaking yet since I have not had the bike running, but the pilot jet and passeges are surely clean. You will have to be very careful not to hit the jet with the tap or the drill bit or you will be replacing.

Good luck

swooshdave · Jan 31, 2010

byrdman76 said:
On my 930's I drilled the plug out on mine out with 13/64 drill bit and cleaned the pilot and passages - I did not try and remove the jet. This seems to me as the only way to ensure that the jet and passages on both sides of the jet are truly clean. If not it will just force the debris possibly into the passage on the other side of the jet and "hopefully" come out. I then used a bottom 1/4-20 tap to tap the new whole that I drilled, and then sealed the hole up with a self sealing 1/4-20 set screw. I have not tested this for leaking yet since I have not had the bike running, but the pilot jet and passeges are surely clean. You will have to be very careful not to hit the jet with the tap or the drill bit or you will be replacing.

Good luck

Since I'm scheming on replacing the jet, I'm not too worried. Nice tip on the tap.

swooshdave · Jan 31, 2010

JAYMAC said:
Hi Dave, there are a few old posts on here about this but you can get some useful info at http://www.jba.bc.ca/Bushmanss%20Carb%20Tuning.html
Cheers John Mc

http://www.jba.bc.ca/Bushmans Carb Tuning.html

Corrected link.

Cookie · Jan 31, 2010

Dave,

If those are off a Norton no problem. If they are off a Triumph they may not have a little casting ground down on the side. On some Nortons this can cause one carb to cock and have an air leak.

swooshdave · Jan 31, 2010

Cookie said:
Dave,

If those are off a Norton no problem. If they are off a Triumph they may not have a little casting ground down on the side. On some Nortons this can cause one carb to cock and have an air leak.

I think I know what you are talking about. I'll post a pic later to check.

MichaelB · Feb 1, 2010

Cookie said:
Dave,

If those are off a Norton no problem. If they are off a Triumph they may not have a little casting ground down on the side. On some Nortons this can cause one carb to cock and have an air leak.

It's the inner idle screw casting.
A few file passes will correct it.

byrdman76 · Feb 1, 2010

swooshdave said:
JAYMAC said:

Hi Dave, there are a few old posts on here about this but you can get some useful info at http://www.jba.bc.ca/Bushmanss%20Carb%20Tuning.html
Cheers John Mc

Click to expand...

http://www.jba.bc.ca/Bushmans Carb Tuning.html

Corrected link.

Wow swoosh that is an awesome link. I would dis-regard my post and just follow that one to the letter...

swooshdave · Feb 1, 2010

The detachable pilot jet caused problems with some 4 Stroke engines. The remoteness of the jet from the two pilot circuit outlet holes caused starting and idling problems on bikes with lower manifold vacuums, and could cause stalling during deceleration due to a weak mixture. The introduction of the pilot bush moved the pilot jet nearer to the outlet holes to overcome these problems.

Just how silly would I be to ignore this and try to use the screw in jets?

Yeah, it's from here...

But then there is this from AMR:

If the jet orifice has been enlarged beyond a certain point, it will become impossible to supply enough air to the pilot circuit to lean out the mixture to a viable specification. When such a case has occurred, we recommend drilling out the damaged pilot jet and installing a screw-in version in the old position.

pete.v · Feb 2, 2010

I got a #78 drill and carefully epoxied it into a stem of a Q-tip. Worked like a charm. Buy 2, you invaritably loose one or break one. They are sooooo small. You need the extention to get to the orifice of the pilot.

swooshdave · Feb 2, 2010

pvisseriii said:
I got a #78 drill and carefully epoxied it into a stem of a Q-tip. Worked like a charm. Buy 2, you invaritably loose one or break one. They are sooooo small. You need the extention to get to the orifice of the pilot.

I have the drill and am now leaning to leaving the pressed in pilot alone.

My other question is that I need new slides, and I saw Amal has three kinds:

Zinc
Aluminum with Chrome
Brass with Chrome

I'm leaning towards the middle one and hoping the bores aren't too worn. Or finding some used ones and see if they work.

swooshdave · Feb 6, 2010

I sandblasted the bowls and manifolds.

Then I mocked up the carbs. No internals.

I also worked some more on the air cleaner. I had stripped the paint off this part and then gave it a bit in the blasting cabinet. Then primer and paint. The other piece will get blasted and painted later.

DogT · Feb 6, 2010

Don't those heat insulating gaskets go between the manifold and the head?

Dave
69S

swooshdave · Feb 6, 2010

DogT said:
Don't those heat insulating gaskets go between the manifold and the head?

Dave
69S

I have two kinds, the thick rubberish ones and some thinner heat resistant ones.

No, I don't remember which go where. But that's what I have you guys for.

swooshdave · Feb 6, 2010

Cookie said:
Dave,

If those are off a Norton no problem. If they are off a Triumph they may not have a little casting ground down on the side. On some Nortons this can cause one carb to cock and have an air leak.

Sorry for the bad photo but you can see the castings here. I think I should be good.

One of the pitfalls when working on a bike that you aren't trying to do a 100% restoration is that as soon as you refinish one part and put it next to one you hadn't intended you get what we call a disparity.

Luckily I'm more interested in getting the bike together than perfect. :mrgreen:

swooshdave · Apr 22, 2010

Playing around with the carbs some more.

I found two thicknesses of O-rings. The thicker one is 2.5mm dia. Which is right?

I mocked up one of the carbs. Do I have the spacers in the right order? They look right.

Just for shits and giggles I dug up these velocity stacks I've been sequestering for untold years.

It looks pretty cool but I think I'll save them for my Triumph project...

MarshalNorton · Apr 23, 2010

Dave,
I have 932's and was suprised during clean and rebuild to find .025 screw in pilot jets in the bottom of the bodies.
I just cleaned them and left them in .
The #78 drill bit was used to clean out the mixture screw orifice. I do not know if my bush was drilled out by previous
owner or not? If not, I can report I have no idling problems or problems richening up the carbs.
Put them in w/o doing any mods to the body and try it.
If it's too constrictive, then bore out the old bush in the body and use the appropriate screw in jet.
Remeber you can't go backwards.
Marshal

L.A.B. · Apr 23, 2010

swooshdave said:
I found two thicknesses of O-rings. The thicker one is 2.5mm dia. Which is right?

= The thin one. (The thicker one is for Triumph twins)

swooshdave said:
I mocked up one of the carbs. Do I have the spacers in the right order? They look right.

Normally there wouldn't be any insulating gaskets between the carbs and manifolds, only the O-rings, but they are not going to do any harm provided they do not cause any air leaks?

pete.v · Apr 23, 2010

Do yourself a favor and true up all flanged surfaces. I am sure all carbs have been overtighted at one time or another. A layout block or plate glass and fine emery. A good mill file is what I use. I also removed the studs from the adapters and did those too.

If those spacers are 32mm they may be ok but they sure were not designed for them. When those surfaces are true, you will feel the oring when you tighten them up. It feels good.

Amal Retentive

swooshdave

JAYMAC

byrdman76

swooshdave

swooshdave

Cookie

swooshdave

MichaelB

"Sons of Arthritus"

byrdman76

swooshdave

pete.v

swooshdave

swooshdave

DogT

swooshdave

swooshdave

swooshdave

MarshalNorton

L.A.B.

Moderator

pete.v

Similar threads