Vboost not working... how to troubleshoot?

[sblankert]

I recently rescued a 1986 Vmax from some young air force fellow who was moving overseas and more or less dumped it due to "engine problems."

The "engine problems" were dirty carbs that were fixed using the shotgun approach listed in these forums (thank you very much), but I think the Vboost isn't working. On my 2007 max, when I turn the key, the vboost servos cycle and you can hear it, but that doesn't happen on the 86 max.

Not being an electrician, I'm not sure how to go about testing the vboost to see what component(s) needs replacement. If anyone could explain to me what to look for on a multimeter, or if there is a quick and dirty way of testing the servo motor or boost circuit, I'd be very thankful.

 

[DMAN999]

Look at Chapter 7 page 59 through 66 of the Service Manual:
https://dl.dropboxusercontent.com/u/55030067/VMX12%20Service%20Manual.pdf

 

[Hellboy]

Many times it is the control box that is under the Left side scoop. The control box is the one that is about 3 inches square or so and has two leads, a squarish one and a round one. If you turn the key on and don't hear it cycle, leave the key on and push on or squeeze this box and see if you get it to cycle. If so, it's the control box. I'm waiting on a replacement at the moment. Also maybe the previous owner has unplugged the leads to stop it in the open position, this is not uncommon. You could also just remove the working one from your 2007, one screw and two plugs and try it in the 86. These are the two simple things you can check very easily, I'll leave anything more involved to others.

Matt

 

[2006 V Max]

Anyone know FOR SURE if the 2006 model Vmax has a vboost? I was told it does NOT. Mine hauls assume but there is no boost at 6000 rpm. I road one back in the early 80s and know all to well the difference of it working or not.

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[2006 V Max]

Typo... should say hauls Ass.

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[Traumahawk]

Anyone know FOR SURE if the 2006 model Vmax has a vboost? I was told it does NOT. Mine hauls assume but there is no boost at 6000 rpm. I road one back in the early 80s and know all to well the difference of it working or not.

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Answered on the other thread.