LiftMaster Q025 / K17-50098 Motor Pulley — 2-1/2-Inch OD, 1/2-Inch Bore

The LiftMaster Q025 supplier SKU identifies motor pulley K17-50098, described in current manufacturer parts information with a 2-1/2-inch outside diameter and 1/2-inch bore. It is used in documented CSW200 and SL3000 drive arrangements, subject to exact model and motor-shaft verification. Some older family literature gives conflicting bore wording, so compare the installed shaft and current supplied part before ordering. This motor pulley is separate from the larger gear-reducer pulley, belt and complete motor, and a matching outside diameter alone does not establish the correct shaft fit.

Compatibility — Models, Versions and Exclusions

Verify the Motor Shaft and Belt Alignment Before Ordering

Inspect the existing motor shaft and pulley interface rather than relying on an old invoice that says only motor pulley. Current manufacturer information describes a half-inch bore, while some legacy diagrams contain different wording. Have the technician confirm the actual dimensions and replacement reference before the repair is scheduled; do not machine a mismatched pulley to force a fit.

Check the belt, mating reducer pulley, retention hardware and alignment during the same inspection. A new pulley cannot repair a damaged shaft or incorrect belt path. Preserve the approved drive ratio and manufacturer adjustment method. Changing pulley size to increase speed or tightening the belt beyond the specified setting can create new problems instead of repairing the original fault.

Specifications and Product Identification

Before Ordering

• Record the complete operator model and existing motor identification.
• VerifyQ025 /K17-50098 and the actual shaft diameter.
• Compare outside diameter, belt path and retention arrangement.
• Inspect the belt and mating components and confirm current package contents.

Package Contents and Separate Requirements

This offer identifies the motor pulley. A motor, belt, gear-reducer pulley, gearbox, shaft key and complete set of retaining hardware are not promised as included. Confirm the current carton and any separately required pieces before ordering. The motor and surrounding drive shown in an operator diagram are not the inventory of a pulley-only service item.

Safety Warnings — Read Before Installation or Service

• WARNING: A moving gate and exposed belt and pulley drive can cause serious injury. Installation and service require a qualified gate-systems technician.
• Isolate AC power, batteries and any solar supply as applicable, and secure the gate against unexpected movement before work begins.
• Keep people clear of the gate and drive during supervised testing. Never bypass required entrapment-protection devices or increase force to overcome a mechanical fault.
• Restore all covers and guards, then verify travel endpoints, reversal and every required safety device before returning the gate to normal operation.

Related Products and Important Differences

• LMRRUL monitored photo eye — a separate protection option only where the exact operator and control revision approve it; not a universal legacy retrofit.
• LMWEKITU monitored wireless edge kit — a separate edge communication system for approved controls and resistive edges; not a replacement for this mechanical or electrical service part.

Frequently Asked Questions

Is this the gear-reducer pulley?

No. It is the motor pulley; the reducer pulley has a separate service reference.

Which bore should I order against?

Current manufacturer information identifies 1/2 inch. Confirm the installed shaft and supplied part because some older literature conflicts.

Can I alter the bore to make it fit?

Do not improvise the shaft connection. Resolve the correct part and dimensions before installation.

Does it include a new belt?

A belt is not promised as included and must be inspected and selected separately.

Need Help Confirming the Right Product?

Contact Garage-DoorParts.com before ordering. Send the full equipment model, readable part labels and photographs of the installed assembly. Include the dimensions, electrical configuration or accessory details relevant to your project so the listing can be checked against the actual installation.