Vboost flap position

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Kalchev

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I seem to have an issue with the vboost. Last year when I got the max ('88 full power) I noticed the cable of the vboost had a bit of slack. Didn't pay much attention til this year's check-up. We had to use washers between the cable housing and the servo motor to take up the slack. The result is it's now possible to pull the black plastic box that holds both vboost cables all the way up to its top position with both vboost flaps perfectly horizontal when fully open.

Problem is when the servo loosens the cable during the startup check. Flaps are not closed fully in that position - I can feel the gaps between housing and flaps with my finger when they should supposedly be closed.

So this brings me to my question, to which I couldn't for the life of me find an answer neither here, nor in the vmax service manual.

On a stock setup: should the vboost flaps be perfectly vertical when closed and perfectly horizontal when open?
I admit never to have taken apart and in detail peek a look inside the vboost tubes to see if there are any flap position markers, but I believe through sheer logic that this should be the setup for the system to work at all...

As it is now, if you try to reverse the cable as it was, the closed position feels more like this -> / (approx.flap angle) and the open position is probable 15-20 degrees shy of horizontal....

Anyone investigated the flap positions on a stock setup :ummm:
 
I seem to have an issue with the vboost. Last year when I got the max ('88 full power) I noticed the cable of the vboost had a bit of slack. Didn't pay much attention til this year's check-up. We had to use washers between the cable housing and the servo motor to take up the slack. The result is it's now possible to pull the black plastic box that holds both vboost cables all the way up to its top position with both vboost flaps perfectly horizontal when fully open.

Problem is when the servo loosens the cable during the startup check. Flaps are not closed fully in that position - I can feel the gaps between housing and flaps with my finger when they should supposedly be closed.

So this brings me to my question, to which I couldn't for the life of me find an answer neither here, nor in the vmax service manual.

On a stock setup: should the vboost flaps be perfectly vertical when closed and perfectly horizontal when open?
I admit never to have taken apart and in detail peek a look inside the vboost tubes to see if there are any flap position markers, but I believe through sheer logic that this should be the setup for the system to work at all...

As it is now, if you try to reverse the cable as it was, the closed position feels more like this -> / (approx.flap angle) and the open position is probable 15-20 degrees shy of horizontal....

Anyone investigated the flap positions on a stock setup :ummm:

YES-constantly.
 
Cheers. After setting it up perfectly horizontal when open there's now a small gap (probably 2-3mm) when 'fully' closed. Not sure how this will affect the mileage or performance :ummm:

It might actually help. At part throttle, having Vboost open will actually lean you out a little bit, but I dont know how much 2-3 mm will actually change. The Vmax is actually rich from the factory, so leaning it out will help.
 
Cheers. After setting it up perfectly horizontal when open there's now a small gap (probably 2-3mm) when 'fully' closed. Not sure how this will affect the mileage or performance :ummm:

This will affect performance and as stated above is not a solution to curing a rich factor by making it leaner. If you want it leaner change the jets. You can set it closed by removing the carbs making sure the venturis are closed and adjusting the cables. Leaving partially open is a mistake.
In the manual there is showing of how to set the vboost.
http://vmaxoutlaw.com/tech/VMX12-Service-Manual.pdf
 
Vboost sync is covered in the Clymer manual. Most likely, is is set incorrectly from the factory. There are 3 adjustments to make. The cable adjusts hie dar open the butterflies open. One is a set screw and is like adjusting the idle screw. The last adjusts the left butterfly with the right.


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