The cam timing procedure is the same for pretty much all Honda small engines.
-Remove spark plug
-You will need to remove the "rocker box" from the top of the cylinder head.
-Remove the large plug in the center flywheel cover to allow the use of a socket the correct size for the flywheel to rotate the crankshaft. The plug will be an extremely large common screwdriver slot
-Remove smaller plug in the same flywheel cover to expose timing sight hole and note the timing alignment mark in the side of the sight hole itself. Again, another very large common screwdriver slot although not as large as the first.
-Remove cam chain tensioner found on the side of the cylinder near the base of the cylinder. (You may want to leave the tensioner in place for checking timing, but it will need to be removed to change timing if necessary)
-With the rocker box removed, the camshaft is now visible. Rotate the engine forward until both cam lobes are facing the piston, kind of like an inverted "V".
-Note that on the side of the cam gear that faces outward, there are two timing marks. With the cam lobes down in the inverted "V" position, both of these marks should be aligned parallel with the rocker box mating surface of the cylinder head. This is the position the cam should be in for timing.
----------------------------------------Now to check timing---------------------------------------
-While looking into the sighting hole on the flywheel cover with a small light, if the cam is timed correctly you will see a "T" mark etched into the flywheel that aligns with the timing mark in the side of the sight hole. This alignment mark in the sight hole is usually a line cut into or near the threads for the sight hole plug. If the "T" mark is not aligned with the timing mark in the sight hole, or at least visible in the sight hole, you need to correct the cam timing.
----------------------------------------To correctly set cam timing------------------------------------
-Using the appropriate size socket, extension, and ratchet, turn the crankshaft via the flywheel nut until the "T" mark is aligned with the timing mark in the sight hole. Note the position of the cam timing marks in relation to the rocker box mating surface of the cylinder head.
-Keeping in mind that the cam lobes must be down in the inverted "V" position, note which direction you must rotate the cam without turning the crankshaft in order to attain proper timing.
-Remove cam chain tensioner to release tension on the cam chain allowing timing to be adjusted
-At this point, you should be able to manipulate the cam under the cam chain, rotating it to the correct timing position. I'm trying to explain it.... In a way of speaking, "walk" the chain around the cam gear using the slack present in the chain from removing the chain tensioner.
-Once you have the cam timing marks now parallel with the rocker box mating surface, verify that the "T" mark is still aligned with the timing mark in the sight hole. Sometimes during the course of adjusting the cam at this stage, the crank is scan be moved by mistake.
-Once both marks are confirmed to be in alignment, you can now install the cam chain tensioner and verify that timing is still correct with the cam chain properly tensioned.
------------------------------How to re-install cam chain tensioner, IMPORTANT!------------------------------
-In the end of the cam chain tensioner assembly that is furthest from its mating surface (base) there will likely be a third bolt. This bolt plugs the hole allowing access to the tensioner, facilitating retracting the plunger for installation preventing damage to the tensioner assembly.
-With this bolt removed, insert an appropriately sized common screwdriver into the hole. Once you seat the screwdriver, rotate the screwdriver (usually counter-clockwise to retract) and retract the tensioner plunger. Think of this as a spring loaded screw you are keeping the spring from turning by holding it with the screwdriver... because that is about exactly what it is..
(There is a special tool available retracts and holds the tensioner plunger in place while you reinstall the tensioner assembly on the cylinder. I have found that I can just hold it with the screwdriver and get the bolts started with the other hand, YMMV)
-The bottom line here is that you want to avoid bolting the tensioner in place with the tensioner plunger fully extended. This will damage the automatic tensioner.....
-Have your ratchet handy for the 2 tensioner assembly mounting bolts, and while still holding the screwdriver that is keeping the plunger retracted, snug the two mounting bolts.
-Once the mounting bolts are snug, pull the screwdriver out, releasing the tensioner plunger. You may hear it take up.
-Now that the tensioner is in place and the cam chain is tight, reconfirm cam timing is correct.
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Now, clean the sealing surface on the rocker box and the cylinder head. I like to use a clean rag soaked in carb cleaner or brake cleaner. Honda does not use an actual gasket in this application, they use sealant. I use Threebond, just like what many of us use on our saws when we do a base gasket delete...
I hope this proves helpful to you.
