VOES help sought
Thread Starter
|
Road Warrior
Joined: Apr 2018
Posts: 1,347
Likes: 820
From: Moneta, Virginia
VOES help sought
I posted earlier this week about a precipitous drop in gas mileage on my 97 EVO. I was lead to check the VOES switch.
The switch shorts at 5 Hg in vacuum. It goes open again at 4 Hg. The system doesnt hold vacuum, it leaks down slowly until the switch goes open, then swiftly declines to zero.
Is this normal operation?
Im checking this on the bike, the hose is still connected through the Tee to the stock petcock and the ground is still connected.
In removing the air box for access I noticed the x-over breathers on both sides connected to the heads a bit loose... could this be the cause of my mileage woes?
The switch shorts at 5 Hg in vacuum. It goes open again at 4 Hg. The system doesnt hold vacuum, it leaks down slowly until the switch goes open, then swiftly declines to zero.
Is this normal operation?
Im checking this on the bike, the hose is still connected through the Tee to the stock petcock and the ground is still connected.
In removing the air box for access I noticed the x-over breathers on both sides connected to the heads a bit loose... could this be the cause of my mileage woes?
Last edited by GOGOBECK; May 5, 2018 at 10:20 AM.
Grand HDF Member
Joined: Nov 2009
Posts: 4,315
Likes: 1,663
From: Tampa
No, vacuum should maintain itself within the VOES.
Try this. Grab a short length of tube, submerge the VOES in a container of water, and blow into the hose (or use a vacuum/pressure hand pump if you have one) to see where the leak is. Mine was leaking out where the wires are.
DON'T pull vacuum when it's under water, for obvious reasons...
Try this. Grab a short length of tube, submerge the VOES in a container of water, and blow into the hose (or use a vacuum/pressure hand pump if you have one) to see where the leak is. Mine was leaking out where the wires are.
DON'T pull vacuum when it's under water, for obvious reasons...
Thread Starter
|
Road Warrior
Joined: Apr 2018
Posts: 1,347
Likes: 820
From: Moneta, Virginia
Thanks for the tip, I can use a syringe to put silicone around where the wires exit the VOES. If that doesnt change things I think Ill buy a new VOES before I remove it from the bike.
Shes running fine, no coughing, sputtering or backfire.
Just chasing the mpg thing!
Another question: when does the carb generate vacuum to the VOES... at idle or at a particular rpm?
Shes running fine, no coughing, sputtering or backfire.
Just chasing the mpg thing!
Another question: when does the carb generate vacuum to the VOES... at idle or at a particular rpm?
Road Master
Joined: May 2012
Posts: 1,001
Likes: 107
From: Houston
I just replaced my VOES. Was getting horrible MPG and wouldnt idle worth a crap. Idle would surge up and down. Also made weird noises when accelerating. I tried my VOES on the bench by sucking and blowing into hose. Micro switch would move but not continuity. Also my switch would stay in whatever position I blew or sucked. It wouldnt spring back. So I opened it up and there was a tiny hole in the diaphragm, also tested the micro switch with my finger and still didnt work. Replaced it and Ive nver been happier
Seasoned HDF Member
Joined: Jun 2010
Posts: 9,332
Likes: 3,873
From: Upstate New York
I went through the same issue a few years back. My 20 year old VOES suffered a split diaphragm, and the switch stuck in the "full advance" position. Bike pinged like a !#$@**%. I tested it and it wouldn't hold vacuum at all, so in addition to a non-functioning switch, I had a small manifold leak.
Thread
Thread Starter
Forum
Replies
Last Post
