Help identifying ports on head

[Yes_chick]

Hello all, new to the xs world. Just picked up a '72 project and am having trouble identifying a couple ports on the engine. I have searched high and low on the internet and cannot for the life of me find out what they are for. The ports in question are located on the cylinder head below the intake ports. Attached pics for reference. I also received 2 spare engines with the bike itself and neither of them have the ports in question, however the previous owner did say they were a later yr production. Thanks in advance for any direction

 

[azman857]

Those are XS1 heads with the #1 cylinder exhaust cover held on by 3 nuts. later heads have 4 nuts Holding on the cover. The ports under the intakes are balance ports. There is a tube that normally connects the 2 intakes.

 

[Wulfbyte]

Welcome to the site yes_chick, if your talking about the two ports connect by that tube on your intake boots,they are vacuum ports for a vacuum fed petcock! The boots appear to be upside down ,the ports should be pointing out and up with One end of tube connected to one and the other end to petcock! Other vacuum port can be capped off! Maybe PO did this because the petcock is a free flowing type! You will find plenty off help and knowledge here and if I’m wrong one of the gurus will definitely know the answer! Good luck hope this helps a lil! Send pics of your xs!

 

[Wulfbyte]

I see the ports now! Thanks azman! See chick ,these guys definitely know their bikes!

 

[Yes_chick]

Thanks for the warm welcome and fast responses! I'm guessing the previous owner installed that hose due to a free flowing petcock. Pointed out with orange arrow. The red circled ports are what I'm concerned about. Are they just balance ports? Is it as simple as running a hose between them? I'll try and get some better pics of the bike tomorrow when I get home from work!

 

[azman857]

The small ports on the intake manifolds (under the cage)they are usually on top and yes if you have a vacuum petcock you connect to that port on the #1 cylinder and blank off the #2 port.

 

[gggGary]

Welcome aboard yes 70-71 heads, barrel is later with 6 bolt cam chain tensioner.
Your ports can be connected or plugged, either way is fine. If we see a shot of the carb intakes we can prolly ID what year the carbs are. You will want to know what the base line jetting is for your year of carbs (trust me)

 

[5twins]

Yes, I can tell by the angle bracket across the bottom of your carbs in one of your pics that they are a later linked set, but as Gary said, exactly which set will need more and better pics to I.D.

 

[Yes_chick]

Awesome thanks a bunch gggGary! I will proceed with connecting the ports the next time I have free time to tinker with it. I was able to snag some shots of the carbs. 5twins you are correct they are a linked set. The previous owner gave me 3 boxes of carbs and misc parts along with 2 almost complete spare engines. I have another set of linked CV's and probably 2 sets of VM's that will have to be gone through at some point

 

[5twins]

Those look like the BS34 carbs, originally used on the 1980 to 1983 models. They were all jetted the same but are considered quite lean compared to the earlier carb sets. Any changes made to intake and/or exhaust are going to require some rejetting.