OK here's the finished product (I think).
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Honda Foreman 500 Valve Adjustment
1) Flat head screwdriver
2) Phillips head screwdriver
3) 10mm box wrench
4) 10mm socket with extension
5) 24mm socket or box wrench (not a perfect fit, but it works)
6) Feeler gauge
7) spark plug wrench
In order to get to the valves you must remove the gas tank and all those plastic shrouds and covers..
The first step is to remove the seat and the stock intake snorkel. There is one plastic Phillips head screw you remove and the snorkel just pulls out of the airbox with a tug.
Next you need to pull off the rubber heat shield over the carburetor. Use the blade screwdriver to pull out the 2 plastic rivets (circled in red), and then pull the cover off the tab (in blue).
The next step is to pull off the gas tank shrouds. Pull out the plastic rivets with the blade screwdriver again, there should be 4 on the right side and 5 on the left. Leave the two rivets on the back of the gas tank shroud in place, it will be easier to remove and reinstall the fenders. There are also two 10mm bolts you must remove. Rivets in red, bolts in blue.
When you remove the fenders the gas cap needs to be removed, also there is a plastic tab you must pull out of a rubber grommet. It’s very hard to pull out, so be careful not to bend or break it as you are removing it.
Moving along now, the gas tank is ready to be pulled out. Pull off the two rubber straps located at the rear of the tank, one on each side:
Then remove the two 10mm screws from underneath the headlight pod:
Now there are two hooks on the front of the gas tank that are holding wires, bend them out and remove the wires. Lift up on the tank slightly and pull it back a few inches. Now you need to unplug the fuel level indicator wire located just in front of the accessory outlet (circled in red). Pull the small tab outwards to release the plug (in blue):
Now you can turn the gas tank around and set it on top of the airbox.
Remove the plastic cover underneath the gas tank by pulling it up and moving the throttle and choke cables. There are two rubber pieces attached to this that are attached by a tab on each side. Also be sure to release the zip tie on the right side framerail.
Finally we can see the engine! By now it’s time to take a break and stare at the beauty of it, after all this is really the only time you can easily see all the major engine components of the new Foremans:
Use the large 24mm socket to remove the valve inspection covers.
The next step is to remove the spark plug. This is to relieve the compression in the engine when you get it to top dead center.
Once you have the engine at top dead center it is finally time to check those valves. Using the .006in or .15mm size insert the feeler between the valve spring and the rocker arm. It should slide in fairly easily with just a slight drag. Most likely it won’t though.
Using a 10mm box wrench loosen the small nut.
Insert the feeler gauge and with the blade screwdriver turn the adjuster slightly to the right to tighten, or the left to loosen. It should barely have to move. While you slowly twist it wiggle the feeler gauge until you feel it start to drag. Again, you should just feel the metal dragging very slightly. I could not do this and take a photo at the same time. Sorry!
The next step is to tighten that nut back up. Make sure to keep a screwdriver on the adjuster and hold it steady as you tighten the nut. Afterwards check the clearance again with your feeler gauge.
Now repeat the process on the other valve.
Replace the two covers for the inspection holes and start the ATV. If it sounds good then start putting it back together, if it ticks than something is loose