Vacuum Leak at Petcock?

My petcock has an unplugged vacuum port. This would mean somewhere there is an open line doesn't it. I don't see a vacant line aside from the line at the bottom of the tank which I have run between the engine and battery housing. I think it is a vent line. It is over revving like a mad dog, if mad dogs over rev. Any ideas?

Take a look at the carbs (on top). Between #1&2 and between #3&4 you should see a port for the vent tube. These 2 ports will be in the same relative positions on the carbs and should each have a hose venting to open air. Now, look again between carbs 1&2. If your carbs were originally set up for a diaphragm type petcock you will see a 2nd port located in a different relative position than the vent ports. That should hook up to the petcock. Ed

Here is what I see the ports on 1&4 are connected with a hose there is a T fitting in the middle with a cap on it (thereby making it one piece of hose. The #2 port runs to a nipple in the emissions unit just behind the steering neck. The #3 port is plugged. The fuel line (with the filter)in the above picture goes to the rear of the carbs in between #2&3 to a main fuel line. I have tighten all the holders. With the tank off and thereby eliminating the petcock with the remaining fuel in the line, the engine still over revs. The only remaining unattached tube is pictured below.

That unconnected nipple on your fuel tap is for a vacuum line.

In the bottom pic it shows the tap lever in the prime position and that would allow fuel to flow to the carbs with out the vacuum being hooked up.

I don't know about the hose under the tank other than to guess it has something to do with emissions.

Try backing off on the idle screw a bunch.

What bike is this, the 650 ?

I'm guessing this is on your 1100.
On the kz650s, the vacuum connects to carb #2, just in front of the vent hose;
Green line in this picture:

Can you post up a picture of your carbs?

I'm sorry I don't really know how to do the MS Paint application.

<a href=" s1307.photobucket.com/user/cerictaylor/m...zpsa3b88940.jpg.html " target="_blank"> i1307.photobucket.com/albums/s599/cerict...ront_zpsa3b88940.jpg " border="0" alt=" photo CarbFront_zpsa3b88940.jpg"/>

Yellow is connected w/ a T fitting and run to the emissions valve behind the steering tube. Red goes to the petcock. And # 3 is Plugged. You can see to the rear of the picture or behind the carbs (which I guess all you can view is the top of the line, but it is the incoming fuel line to the main fuel line.

Have a look here.
I'm not really getting where the vacuum connects on the BS carbs:

www.wgcarbs.com//index.php?option=com_co...sk=view&id=Itemid=86

Ooops. I didn't realize you had BS carbs. My comments above were for VM carbs. Ed

NO my OOOPS. I had cranked up my idle screw a good bit before I tore down for the rebuild. Now that the engine is running more efficiently it started overrevving. I guess. I appreciate the feedback.