To adjust the valves, start by removing the rocker covers and spark
plugs from the cylinder heads. While looking through the spark plug
hole, rotate the crankshaft until the piston comes to TDC (top dead
center) with both rocker arms in the horizontal position (both valves
closed). You will note that both rocker arms are slightly loose in
this position. This should be the combustion stroke where you can
rock the crankshaft side to side without the rockers moving. If the
rockers move immediately when the crankshaft is slightly rocked
either way, this is between the exhaust stroke and intake stroke.
This position should not be used to adjust the valves as it is easy to
make a mistake in this position.
Using a box end (closed end) 7mm wrench and a 2mm socket head
wrench (Allen wrench), loosen either of the rocker arms one at a
time. Completely adjust one rocker arm and retighten before
starting on the other. Either the exhaust side or intake side can be
adjusted first. The sequence does not matter.
The adjustment starts by loosening the adjuster screw’s lock nut
with a box end 7mm wrench while holding the adjuster screw in
place with a 2.5mm socket head wrench. The engine needs to be
completely cooled down to room temperature (app. 70°) before
starting the rocker adjustments. At this point, turn the adjuster
screw down (clockwise) until it just removes all slack from the
rocker. A feeler gage is not necessary for these adjustments. Be
cautious not to turn the adjuster screw too far as you only want the
slack removed. When you are satisfied that all the slack is
removed, tighten the lock nut while holding the adjuster screw
firmly in place with the Allen wrench. In some cases, tightening the
lock nut will change the setting you have established. If this occurs,
loosen the lock nut and start the procedure over until the setting
stays constant after the lock nut is tightened.
