vacuum line to regulator?

[philwarner]

I traced this vacuum line from a T between the carbs to what I assume is the voltage regulator.  What is the function of this vacuum line?

[guzzista]

Vacuum signal to Marelli Plex ignition module

[Antietam Classic Cycle]

I traced this vacuum line from a T between the carbs to what I assume is the voltage regulator.  What is the function of this vacuum line?

I'm not real familiar with that ignition system, but IIRC it alters the advance curve of the ignition timing.

[philwarner]

Wow!  You guys are quick.  So... ignition module.  That makes more sense.

  If I disconnect that line to connect lines to each carb to do a carb balance, will I have any ignition problems at idle or at 3-4 thou RPM?

[guzzista]

No need . There are 6mm shorty Allens ( 5mm head) just for that purpose on your manifolds

[philwarner]

No need . There are 6mm shorty Allens ( 5mm head) just for that purpose on your manifolds

I am not recognizing the 6mm shorty allens you refer to.  I see a phillips head screw on the underside of the manifold



and a tiny bib on the backside that I assume is a breather for the carb bowl.

[Murray]

I am not recognizing the 6mm shorty allens you refer to.  I see a phillips head screw on the underside of the manifold
[
and a tiny bib on the backside that I assume is a breather for the carb bowl.

The philips head in the photo, hopefully some fool hasn't jammed a self tapper in there for you.

[philwarner]

The philips head in the photo, hopefully some fool hasn't jammed a self tapper in there for you.

So I'd need a threaded tube to go in the hole once the philips is removed?  My Carbmate came today, but I don't think it has any accessory tubes with it.

[Murray]

Yes its a standard metric thread 4mm from memory, no acessoory tubes sounds a bit odd to me.

[philwarner]

Yes its a standard metric thread 4mm from memory, no acessoory tubes sounds a bit odd to me.

I just checked MG Cycle and they have a kit of 4 adapters (2 different lengths) with 6mm threads, Part number P510, for $10 or so.  I need to order some tank mount rubber bumpers and washers anyhow since my 96 Cali's frame did not have these nor the holes in the little vertical frame lugs where they are supposed to mount.  Looks like another order is in order.  If I had known the ports were there I could have ordered the adapters with the Carbmate - live and keep learning and keeping the US post office in business.

EDIT:  I just took both screws out and they are M6 X 1 thread and in good shape, so in goes another order.

[Kiwi_Roy]

Its 6mm
Pick up a couple of 6mm grease nipples and file the tip off the threaded end, that will let out the spring and ball bearing leaving you with a hose connection
Just one thing, the connections get hot from the engine so plastic hoses will fall off, use rubber hose for the first few inches or fasten the plastic hose with a twist tie.