Valve Kit fitting instructions for motocross bikes

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Valve Kit Installation Instructions

Begin the instalation of your Zoom Factory Valve Kit by removing:

Fuel tank
Exhaust pipe
Spark plug
Cam chain tensioner
Cylinder head cover

Loosen and slide off carburettor.

Set the motor to TDC (top dead centre) refer to your owners manual for exact information. You can now remove the Camshaft bearing cap bolts or cam carrier. Be careful not to drop the locating clips into the engine when removing bearing caps.

Hook a zip tie or safety wire around the Cam Chain when removing the Camshaft(s) and fix it to the frame to prevent the chain from dropping into the engine.

Drain the coolant
Detach the radiator hoses from the cylinder head
Remove the cam lifters and valve shims (Warning !! the shims can stick to lifters and drop into the engine)
Remove the cylinder head nuts and bolts
Carefully remove the cylinder head

Use a suitable motorcycle Valve Spring Compressor to depress the spring retainers, remove the cotters, and push out the valves. Inspect the valve seats. To get the best performance and durability from new valves it is always advisable to have the old seats re-cut. Check the Valve Guides for wear (see the owners manual for the tolerances) and replace if necessary.

Installing the new Valves;

Replace the valve stem oil seal with a new part.
Apply a thin coat of molybdenum disulfide grease to the valve stem before installing the valve.
Check to make sure that the valve moves up and down smoothly.
Check to make sure that the valve and the valve seat are making proper contact.
Install the valve spring so that the tighter coil end faces the spring seat, and the painted end faces upwards.
Compress the valve spring to install the collets in order to secure the spring retainer in place.
The shim must be installed into the top of the retainer. Apply high temperature grease to the shim or to the retainer to prevent the shim from falling off when the camshaft or (cam carrier) is being installed.
Apply engine oil to the valve lifter surfaces, then install the lifters.

Re install the cylinder head in the reverse order of removal. Refer to the owners manual for the proper torque settings, failure to use the proper torque settings may result in engine damage.

With the camshaft(s) in place and the cam chain tension set, double check that all the timing marks are in the correct position (refer to owners manual), you can now check the valve clearances and adjust if neccessary. It is important to maintain the manufacturers specifications for valve clearance, this information will be found in the owners manual.

After reassembly is finished you can run the engine. We recommend riding at a moderate pace, without any quick bursts of acceleration for the first 20 minutes of riding. The valve clearances should be checked after the first 3 hours running, and after every 10 hours there after.