idle goes up
All three of the above mentioned units can use a VOES; it is optional but use of it will result in decreased fuel consumption, a slight increase in performance, and less chance of pinging. I ran a VOES on my previous 1980 w/Hi-4 and on my current 1978 w/Ultima.
I need the VOES on my '78 to eliminate the pinging which results basically from using Wiseco 10.0:1 pistons.
Install is relatively easy. There is a wire from the ignition module to the VOES, a ground from the VOES, and a vacuum line [small diameter rubber hose] from the VOES to either the carb or the manifold. The usual location is on top of the carb, using the top mount bolt or stud. I use this same stud for the ground.
For the vacuum line, you can either use a carb with a vacuum port [such as a CV] or drill a hole in either the carb or the manifold and install a fitting. On my '80 i drilled a hole in the manifold. Here is my fitting for my '78 ...
I drilled a very small hole, about 1/16", right thru, then enlarged about the first 1/4" of it to accept the hollow tube as a tight press fit. A 1" length of metal brake line is a good choice.
I need the VOES on my '78 to eliminate the pinging which results basically from using Wiseco 10.0:1 pistons.
Install is relatively easy. There is a wire from the ignition module to the VOES, a ground from the VOES, and a vacuum line [small diameter rubber hose] from the VOES to either the carb or the manifold. The usual location is on top of the carb, using the top mount bolt or stud. I use this same stud for the ground.
For the vacuum line, you can either use a carb with a vacuum port [such as a CV] or drill a hole in either the carb or the manifold and install a fitting. On my '80 i drilled a hole in the manifold. Here is my fitting for my '78 ...
I drilled a very small hole, about 1/16", right thru, then enlarged about the first 1/4" of it to accept the hollow tube as a tight press fit. A 1" length of metal brake line is a good choice.
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Road Warrior
Joined: Sep 2006
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From: nj
I am running a S&S carb and looking at the carb and diagram of the carb there is no port that is plugged and looking at the intake there is no port neither. So guess drilling will be my option , I did noticed that you drilled towards the mount any reason why there and not in the middle somewhere of the intake.Thanks again
The first time i did this on another bike i drilled the hole in the intake mani, without enough regard for how it would be mounted. I just chose what looked like the best spot, where the metal was thickest. Well, it was in the way of the mount hardware. So look at the intake/carb/etc while it is all on the bike, and then choose the best spot.
The one pictured is for my '78. It is the original 38mm Keihin butterfly carb. I chose to drill the carb rather then the mani because it has a thicker spot, which is also in a more convenient spot than the best spot on the mani. Also, that spot is where the stock VOES port is located on later carbs, altho that spot on those carbs is built up considerably more.
The piece that i used for the port is actually a hollow bolt that i found a few years ago in my driveway. I kept it because it looked interesting. I suspect that it is part of a bicycle brake system, but i do not know. My indie turned down the head in his lathe. Previously i used the fluted end of a skinny 1" piece of metal brake line - the skinnier the better, it does not need much.
The one pictured is for my '78. It is the original 38mm Keihin butterfly carb. I chose to drill the carb rather then the mani because it has a thicker spot, which is also in a more convenient spot than the best spot on the mani. Also, that spot is where the stock VOES port is located on later carbs, altho that spot on those carbs is built up considerably more.
The piece that i used for the port is actually a hollow bolt that i found a few years ago in my driveway. I kept it because it looked interesting. I suspect that it is part of a bicycle brake system, but i do not know. My indie turned down the head in his lathe. Previously i used the fluted end of a skinny 1" piece of metal brake line - the skinnier the better, it does not need much.
Last edited by IronMick; Dec 3, 2010 at 05:47 PM.
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robjohnston
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Dec 8, 2006 07:45 PM
