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Stuart, > US gsxr's seem to have one conveniently placed in > the rubber boot between the right carb and the head, UK spec 11's also have a vacuum take-off on the #4 carb which is used to provide a signal to the fuel cock. I'm now successfully feeding my dump valve from this point via a short length of 8mm hose. If you also intend to use this point for an *un-damped* boost gauge you will have to severely restrict the hose to the gauge, otherwise the vibration at low revs will shake the pointer off! I use a cheap leak down valve (The type you can buy at any motor accessory shop) as a damper. What I've done is seal the adjuster thread with PTFE tape, then I placed the valve in the pipe between the inlet rubber and the dump valve, connecting the boost gauge to the point where the valve would normally leak air. You can then adjust the valve to damp out the vibration on the boost gauge. > dont.The only other place I can think of is from one of the plastic carb > balancing stubbs on the carb top,but I'm not sure if the small opening > will see enough vacuum to operate the valve quickly? I originally made a manifold which connected to all the carb tops and used this to provide manifold pressure for the dump valve / boost gauge etc. This worked well but was untidy so I opted for using the take-off on the #4 carb rubber. Another point you may find of interest. I originally supplied my boost retard switch (which was set to about 3 psi) with manifold pressure. I found that when steady state high speed crusing with about 3 psi on the gauge the bike surge quite violently. What seemed to be happening was the pressure switch was clicking in and out so the bike would accelerate for about a second, then decelerate for a second. This was bad enough to be quite frightening on a high speed bend which was invariably where it happened! What I did was re-locate the switch so it's now looking at plenum pressure rather than manifold pressure and the problem's gone. Regards Tim Drew -- mailto:timdrew@cix.co.uk -------------------------------------------- For my PGP public key send a blank e-mail to mailto:pgpkey@timdrew.cix.co.uk --------------------------------------------