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XTREME KARTS XF

Vacuum diagram for Thermoquad + tuning

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The floats aren't externally adjustable, the fuel jets and needles should be the right ones for the engine it was designed for, so once installed the only adjustments should be idle mix & speed (as with any carby), vacuum piston and secondary flap spring tension.

 

Idle speed: if you want to run the idle solenoid then that's where you make your adjustment from. If not, you can adjust the base idle screw up so it's there all the time.

 

The vac piston screw changes the relationship between the rods and the piston and changes the mixture under load in the primaries. It's a very fine adjustment and you can go 2 turns at a time before noticing a change. Wind the screw in to raise the needles and make it richer.

 

The secondary flap adjustment is a little involved but from memory you back the lock nut and screw off, let the flap drop and wind it round again till the flap closes. Note where the screw is and keep winding till you reach (I think) 1-3/4 turns. Lock up the nut while holding the screw there. This controls how far the flap opens in relation to airflow over it. Tighten the spring for richer secondary mixture.

 

If it wasn't touched during a rebuild and ran fine before then don't bother touching any of it. They're different from your normal carby and are quite specialised.

 

You can block most of those vac lines as these carbies were designed for Mopars and a couple of Fords, meaning many of them would have been blocked from factory. All you need really is large one for PCV, small constant vac for carbon canister, and ported vac for distributor. How you tell is the first two will pull vac at idle, but distributor vac will only pull vac at above say 10% throttle. The rest are all bullshit really. That one on the top of the carby is the float bowl vent and should go to carbon canister but nobody ever bothers. There are others that go off to vacuum switches that nobody uses these days so just hook up those 3 that I mentioned and you'll be sweet.

 

Start with your idle screws say 2-1/2 turns out and wind them in to go leaner.

 

Best way to tell if it will work is to bolt it on and see!

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1) Vacuum resevoir line from HVAC unit to rear christmas tree (manifold vacuum)

2) HVAC control vac line to hot water valve

3) W (white) vac line from HVAC control to 107 deg C PVS (top port).

4) G (green) vac line from 107 deg C PVS (middle port) back to the left hand foot well diaphragm

 

Borrowed from another (Forum) Post 213 from Paul's 82 XD Ex Pursuit thread on Xfalcon

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