As per the book on resetting the cam chain tensioner.
Set the motor at TDC on the compression stroke. (If you cannot figure this out on your own then disregard the following and take it to someone who can figure it out.)
Remove the 21mm nut and remove the timing chain tesnioner. Taking note on how the tesioner comes out of the motor, and the position of the O ring on the tensioner.
Preparing the timing chain tensioner for installation
Press the timing chain tesioner together completely
This requires some force, as the oil must be pressed out. Without pressure, the timing chain tesnsioner extends again completely. (IE after fully compressing the tensioner when you release it, it will fully extend)
Place two spacing washers or smilar aids next to the timing chain tesnsioner psiton. This ensures that, when pressed in, the piston cannot go in all the way.
Thickness of spacing washers= 2 - 2.5mm or .08 - .98"
Release the timing chain tensioner, the detent mechanism engages and the piston remains in place. Final position of the piston after engagement 3mm or .12".
IE. place two washers, 2 -2.5mm's in thickness, one on each side of the piston and re compress the tensioner until the cylinder of the tensioner comes to rest on the two washers that are on either side of the piston while the piston is on the bench. The internal detent should then engage and when you release the cylinder the piston should not extend fully on it's own, and should protrude from the cylinder 3mm.
Re-install the timing chain tensioner in the motor.
Re-install the 21mm nut and tighten to 30nm or 22ft lbs.
Re move the small nut on the back side of the 21 mm nut.
Using an appropriate drift, push through the hole in the back of the 21mm nut and push the tensioner towards the cam chain. This unlocks the cam chain tensionor.
Re- install the small nut on the back of the 21mm nut and tighten to 10nm or 7.4ft lbs.
You are now done. Start motor and let idle, it may take a bit for the oil to fully fill the tensioner and pressurize it.