Desmog ports - positive or vacuum pressure?

[Black Sled]

Does anyone know what the effect is of inadequately sealed desmog ports?  Do they run vacuum or positive pressure? 

I just cut the tubes off the orginal chrome plugs and filled them with JB Weld.  They are held in place with the original fasteners.  Wasn't sure if these needed to be sealed up air tight or what...

[Dave Weaver]

That is the same remedy I performed, and haven't had any trouble in 2 years.

[Tropic traveler]

Exhaust is what you are capping off. So positive pressure is what you are up against.
I drove a 14mm freeze plug down the 4 top holes & chopped the bottom tube off about 1" away from the "foot" then folded it over & welded it shut. Did both Valks that way.
No problemos!

[Youngsmoke]

Hey,
  I decided to clean my carbs because I have lost some power and thought that mught be the culprit.  When I got the carbs off the bike it ocured to me that this would be the perfect time to desmog my bike.  I found the instructions in shop talk but can't seem to find the freeze plugs that everyone recommends using.  I had heard that they have them at NAPA but when I called today they said all they have is 14.4 mm plugs and they are out of stock.  Are these the same?  if not does anyone know where I can get these freeze plugs?  I need help soon because I have a bike trip planned for laborday weekend, and need to get the bike back together in time.
thanks
Ari

[Rocketman]

they said all they have is 14.4 mm plugs and they are out of stock.  Are these the same?  if not does anyone know where I can get these freeze plugs?

I don't know from personal experience how tight the fit is, but 0.4 mm is a VERY small amount.  I'd be surprised if that's a problem.