SMC Vortex Clutch Manual


The Vortex 4000 is a centrifugal clutch designed for kart racing engines that produce ten horsepower or less at crank speeds of 7000 RPMs (revolutions per minute) or less.

Adjustments - The engagement speed is adjusted by removing the Vortex springs and repositioning the lower leg of each spring in another hole.  The difference between adjacent holes is approximately 180 RPMs.  For an unrestricted stock engine the middle hole will cause engagement at approximately 4000 RPMs.  See diagram below. The optional Vortex Spring Wrench will simplify spring removal and replacement.

Although the weights have holes for attaching more mass, such practice is not recommended because the Vortex springs will not control heavier weights adequately.  Added mass also interferes with the Vortex Spring Wrench.

Clutch Maintenance - IMPORTANT- the top and bottom surfaces of drive plates and clutch disc all wear differently. Upon  disassembly use an appropriate marker to identify the top side of the drive plates and clutch disc if they will be reused.  An upside down clutch disc or drive plate will cause inferior performance.

If the clutch is dusty, clean it with compressed air.  If it is oily, clean it with brake cleaner.   Carburetor cleaner, gasoline, or other petroleum-based cleaners leave an undesirable film on the parts and should not be used.

Protect the clutch from moisture.  Many of the Vortex 4000 parts vane an anti corrosion coating.  The two drive plates do not.   Rusted drive plates will cause inferior performance particularly if the rust occurs where the weights touch the drive plate.  Remove rust in these six small areas with 800 grit sandpaper.

Heat and pressure cause friction material to separate from the clutch disc and bond to the drive plates.  This friction material should be removed from the drive plates with sandpaper.

Drive plates warped in excess of .015 inch should be replaced.  Glazed clutch discs should be replaced.  Clutch discs less than .015 thick should also be replace.  (Recommended spare parts are two drive plates and one clutch disc.)

Tighten the six cap screws with 48 inch-pounds (four foot-pounds) of torque using a size T25 Torx� wrench.

Sprocket Maintenance - Remove the inner race but first note that its inside diameter nearest the crankshaft has a radius and its inside diameter nearest the clutch has a sharp corner.  Clean the bearing with brake cleaner and dry it thoroughly.  Lubricate the bearing with grease.  Reinstall the inner race (check the inner diameters) and retaining rings. See diagram below.

Performance Notes - The Vortex clutch is not very sensitive to air gap.   Small changes in clutch disc or drive plate thicknesses due to manufacturing tolerances and wear will not affect performance.  Excessive heat will warp the drive plates causing zero air gap and consequently clutch lock-up (direct drive).  The clutch disc and drive plates should be considered a matched set.  Heat and pressure cause these parts to wear and deflect together.  If only one or two of these three parts are modified, replaced or upside down, performance may suffer.

Set the engagement speed to the engine's peak torque RPM.  The Vortex clutch engages very smoothly.   Watch the tachometer closely to note engagement RPM.

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