How long does a VOES last?
Is there a recommended change interval?

 

they do two things - the electric part stops working --- or the thing starts to leak vacuum -- yea i have replaced one maybe 2 since they came along in the 80s sold a bunch dont know why - i stoped asking years ago why they need it

 

If you get a new one, could I have your old one? Bwaaaaaaaaaaaaaaaaaa!

 

You haven't updated our signature pic yet? Too busy riding ...

 

So basically there is no time that they should be replaced.
Correct?

 

I had one fail on the Sporty after four years. The original VOES on my '94 Softail went 19 years and 170,000 miles before the diaphragm failed.

I'd check it if I had the tank off for any reason, but it's not something I worry a lot about.

 

I'm very close to that now.

 

When the switch failed on the Sporty, the bike was all but undriveable, as the switch kept going back and forth between the two advance curves at random times, every few seconds. It acted like a real bad manifold leak.

The Softail apparently got stuck on the "advance" curve. The bike ran well, but began pinging under acceleration. After ruling out fuel and the usual suspects, I checked the VOES and found TWO failures. first was a vacuum leak from an punctured diaphragm, and second, the contacts were stuck in the shut (advance) position. This surprised me, because the normal failure mode for a bad diaphragm SHOULD have been to leave the contacts OPEN, and the ignition on the "retard" curve. Vacuum is required to close the switch, activating the "advanced" spark curve. No vacuum-no advance. But my ohmmeter and the way the bike ran didn't lie.

 

No, they're not a service item, although they can sometimes give problems. The only problem I had with mine was a small split in the vacuum hose, which gave some serious riding problems until sorted.

Why do you ask?!

 

Curiosity mainly.
Tina has 19 years and 140k miles and I am just going through her.
Since the VOES has a rubber diaphragm I didn't know how long it would last.