How do you check valve clearance on 2005 Honda CRF450R?

Answer 1

Remove the seat and the and shrouds. Petcock is turned off and fuel line is removed from the carburetor. Drain all fuel from the tank. Next the bolt that holds the petcock is removed. Fuel tank is now removed by loosening and removing the bolt at top and strap that hold it in place. You can now clean the valve cover and the upper part of the engine. Be sure that no dirt falls into the cylinder head after you remove the valve cover. The spark plug cap and crankcase breather tube are next removed. You are now ready to loosen and remove the three valve cover bolts, the crankcase hole cap is also removed as well as its O-ring. Next you should turn the crankshaft clockwise in order to to align punch mark on primary drive with index mark on the crankcase cover. You do the turning with the kick starter. It is easier to turn if you also remove the spark plug. Noe be sure that the piston is at Top Dead Center also called TDC on the compression stroke. You know if it is on the compression stroke when the cam lobes face the back part of the motorcycle and the punch mark and the timing marks are in aligment with each other. The intake valves clearance is measured by sliding a feeler gauge between the cam lobe and valve lifter. The clearance is 0.16+/-0.03mm or 0.006-/+0.001 in. when it is correct. Next you measure the exhaust valves clearance by inserting the feeler gauge between the rocker arm and the shim bucket. The valve clearance here should be 0.28mm-/+0.03 or 0.011-/+0.001 in. Adjust valve clearance to these values by shimming. The shim is the little disk sitting under the valve bucket. It acts as a spacer. As valves gradually get worn, the gap or valve clearance gets tighter and a new and thinner shim needs to be placed under the bucket in order to maintain the correct amount of clearance. The torque for the three valve cover bolts is 7lbf-ft. When you are sure you have adjusted the valves correctly assemble things again, the tank, fuel line and petcock are installed as well as the rdiator shrouds and seat.