I used a rubber vacuum cap from Autozone when I did my PAIR-ectomy. It didn't hold up very well. The cap in the attached pic was on the airbox nipple where the PAIR valve hose was attached. You might want to check yours if you used a similar rubber vacuum cap in that location.

 

I noticed the same thing on mine as well, I used the Dorman kit that came as an assortment and they look the same way.

 

I used an old door stop.

 

How long before it failed? 6 months? 2 years?

 

use electrical tape to wrap the nipple before you cap it.

 

I disabled the PAIR valve in 2003, but didn't remove it until later. I'm guessing that vacuum cap was on there 5 years.

 

Did my pairectomy when I got my bike when I first joined this forum and instead of using the vac cap as a cap, I found one that fit inside the airbox nipple, thereby using it as a plug instead of a cap and it is still just fine. Just an idea...

 

5 years for a $0.60 cap is pretty good though....