Should the Anti-afterburn valve hold vacuum?

Information and questions on GL1200 Goldwings (1984-1987)
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Joined: Sun Feb 15, 2015 2:10 pm
Location: Shreveport LA
Motorcycle: 1983 Gl1100 1978 Gl1000 1983 CB750

Should the Anti-afterburn valve hold vacuum?

Post by LilJohnWayne »

I haven't been able to find this specific test or answer.

Obviously, the air cut-out valve diaphragm will hold vacuum nearly perfectly. But should the same be true for the anti-afterburn valve diaphragm?

If you answer, can you be certain of your own test results? If somebody reads this in the future to repair their GL, I want to be sure they're given the best information.

Here's my test.

I apply vacuum to the air cut-out valve nipple. With about 20"Hg, the needle on my gauge doesn't budge after a minute.
When I apply vacuum to the anti-afterburn valve nipple, it will drop from 20"Hg to 5"Hg in 6 seconds and then it will slow down as the spring expands the diaphragm's chamber which maintains the last bit of vacuum until it drops to 0.


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