What is this thing?!
What is this thing?!
I was reading through Craigfell's Rusty work Hoss thread earlier and I spotted something interesting in one of his photos. Basically it's a bit of small pipework under the tank, it jogged a memory so I looked at mine and found it had become disconnected on one end of the T-piece. I've attached his photo below so you can see what I'm on about, basically I wondered if anyone here knew what it was / did and was it bad that mine has been ridden around with it disconnected for ??? miles. Cheers
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Re: What is this thing?!
Hi,
This is the VTV (Vacuum Transmitting/Transmission Valve).
I posted some questions about this on August 9th last year but I don't feel I have enough knowledge to say more about its function or the effects of it being disconnected.
Ciao
This is the VTV (Vacuum Transmitting/Transmission Valve).
I posted some questions about this on August 9th last year but I don't feel I have enough knowledge to say more about its function or the effects of it being disconnected.
Ciao
Re: What is this thing?!
Thanks SWM, I read through the workshop manual and have found the purpose of this item! Basically, there is a flap in the airbox that opens and closes to allow more or less air volume depending on engine load. Sort of like a simple version of variable length inlet ducts I'm guessing.
Anyway, this tubing controls operation of the flap, so with it open to atmosphere (as mine was with the hose loose) this makes the airbox flap move to the open position as if the engine was running at high RPM. So in theory I was losing some low RPM engine power.
I've extracted the relevant pages from the workshop manual and posted them here under "Intake Air Control Valve.pdf" if anyone is interested in reading how it works:
https://drive.google.com/drive/folders/ ... sp=sharing
Cheers, HiFi.
Anyway, this tubing controls operation of the flap, so with it open to atmosphere (as mine was with the hose loose) this makes the airbox flap move to the open position as if the engine was running at high RPM. So in theory I was losing some low RPM engine power.
I've extracted the relevant pages from the workshop manual and posted them here under "Intake Air Control Valve.pdf" if anyone is interested in reading how it works:
https://drive.google.com/drive/folders/ ... sp=sharing
Cheers, HiFi.
Re: What is this thing?!
Hi HiFI,
Thank you for your response, and especially for the attached 'Air Intake Control Valve.pdf.
If I am understanding this correctly, the VTV is isolating but passing on any change in vacuum to the Air Intake Diaphragm via the Control Solenoid.
So if the VTV was disconnected, no change in vacuum would be passed on, and as you say this would adversely affect mid to top end performance.
Further if it was disconnected on the input side, then changes of vacuum from the Valve Actuator would be open to air (possibly sucking in all sorts of nasties).
Thank you again.
I already have a printed workshop manual, but this seems slightly less detailed than the pdf's you have made available
Ciao
Thank you for your response, and especially for the attached 'Air Intake Control Valve.pdf.
If I am understanding this correctly, the VTV is isolating but passing on any change in vacuum to the Air Intake Diaphragm via the Control Solenoid.
So if the VTV was disconnected, no change in vacuum would be passed on, and as you say this would adversely affect mid to top end performance.
Further if it was disconnected on the input side, then changes of vacuum from the Valve Actuator would be open to air (possibly sucking in all sorts of nasties).
Thank you again.
I already have a printed workshop manual, but this seems slightly less detailed than the pdf's you have made available
Ciao
