Honda XR600/ XR650L Camshaft Installation and removal Instructions


Filed Under (Honda) by admin on 05-12-2011

Remove the tappet covers. Remove the crankshaft cap and timing hole cap on the left engine case cover. Remove the spark plug. Rotate the engine in a counter clockwise direction. Position the engine at true top dead center (TDC) using the mark on the flywheel. True top dead center occurs when both the intake and exhaust valve are closed when the piston is at TDC. This is technically the end of the compression stroke and the beginning of the power stroke. The “artificial” TDC is during the overlap when both the intake and exhaust valves would be open. Since the rocker arms are located in the valve cover on an XR600, true TDC occurs when the cam lobes are pointed downward when the piston is at TDC. Remove the cylinder head cover. Warning, do not drop the locating dowels into the cam chain cavity. There are two dowels, one on either side of the cover. Remove and discard the gasket. Note the positioning of the cam lobes, this will help during installation of your new Hot Cams camshaft. Note also the location of the sealed bearing on the end of the camshaft and the direction in which it is facing. Loosen the bolts that hold the camshaft sprocket. Remove the lower camshaft sprocket bolt first, it will be necessary to rotate the engine. Rotate the engine back to TDC. Release the spring tension on the cam chain tensioner by lifting the end of the spring out of its hole in the tensioner block. A spring tool is a good method. Be careful not to scar the cylinder head’s gasket surface for the cylinder head cover. Remove the allen bolt that holds the end of the tensioner block shaft
just to the inside of the tensioner block. Note the location of the tensioner block shaft cap ridge. Using a pair of pliers pull the shaft out by grasping the ridge and using a clockwise rotation of the shaft while pulling outward. Pull the tensioner block upwards, out of the cylinder head. Remove the top camshaft sprocket bolt. Pull the sprocket off the camshaft but maintain upward tension, do not allow the chain to sag, it is possible for the chain to “slip” on the bottom sprocket of the crankshaft and change the cam timing. Remove the camshaft. Remove the cam bearings. Set the stock camshaft with the auto-decompression aside. It is not possible to use the auto-
decompression on the Hot Cams so do not attempt to re-install. Use a manual decompression. Install the bearings onto the new Hot Cam

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