How to Remove the Clutch on a Husqvarna 450 Chainsaw

Stop the engine and place the saw on your workbench with the chain brake housing upward. Loosen the two chain bar nuts with the combination tube wrench supplied with the saw.

Insert a flat-head screwdriver into the chain tensioner screw on the front of the saw next to the chain bar and slacken the chain tension by turning the adjusting screw counterclockwise.

Remove the two bar nuts and lift the chain brake cover off.

Don a pair of work gloves. Push the chain bar toward the saw and slide the chain out of its groove. Remove both the chain and the chain bar.

Turn the saw upright and unclip the four upper engine cover clips by levering them outward with a flat-head screwdriver. Remove the engine cover and lay it on one side.

Remove the rubber boot from the spark plug and unscrew the plug with the combination wrench. Turn the engine clockwise so that the piston starts to move upward.

Stuff as much 5/16-inch nylon cord into the pug hole as possible to prevent the engine from turning while removing the clutch. Alternatively, insert a metal piston stop into the plug hole and rotate the engine slowly in a clockwise direction until it stops turning.

Pull the chain brake handle all the way back and slip the chain brake belt off the clutch drum.

Insert the tip of the flat-head screwdriver into the right-hand recess on the front of the centrifugal clutch. Deliver a sharp downward hammer blow to the end of the screwdriver to loosen the clutch drum’s left-hand thread.

Spin the centrifugal clutch clockwise off the crankshaft, slide the clutch drum and sprocket off the shaft and remove the roller bearing from the crankshaft.

Drop the bearing into a small container of biodegradable solvent to soak off any embedded dirt, remove all traces of compacted sawdust from inside of the clutch housing with dry 1/2-inch paint brush, and wipe the housing clean with a rag.

Blow the roller bearing clean with a can of compressed air, wipe any remaining solvent off and lubricate it with two or three drops of engine oil.

Replace the bearing and slide the new clutch drum and sprocket onto the shaft. Thread the replacement centrifugal clutch onto the crankshaft in a counterclockwise direction and deliver a moderate blow with the hammer and screwdriver to the left hand recess to snug the drum down.

Slide the chain break belt over the clutch drum and remove the rope or piston stop. Clean the spark plug terminals with a small wire brush and adjust the plug gap with a 0.020-inch feeler gauge and a plug terminal adjusting tool or needle nose pliers.

Replace the spark plug, connect the plug boot and reattach the engine cover.

Reassemble the chain bar and chain. Reinstall the chain break cover and snug the nuts down by hand.

Adjust the chain tensioner screw so that you can lift the chain about 3/8-inch upward in the chain bar groove and tighten the chain bar nuts securely to complete the procedure.