Purchase one Cometic Head Gasket
Take the small cover off the right side of the motor (if you were sitting on the bike) with a 7mm socket. Turn the pickup unit with a 19mm socket to TDC clockwise (your right) you will know the engine is TDC if you take a screw driver and insert it into the #1 piston spark plug hole and the piston is at the top of the cylinder, review the marks on the unit as shown in the picture. One last note on most motorcycles the pickup lines up with the edge of the pickup unit, this is not the case with the XN85 there is a second mark just after that is TDC refer to your shop manual for confirmation.
Remove your Cam Chain Cover with a 10mm Socket. The Engine should look like this. Don't laugh at how dirty this motor is it sat for over 10 years.
Review your Intake Cam timing mark. This is how it should look before and after project is over.
Review your Exhaust Cam timing mark. This is how it should look before and after project is over.
Another way and to do this but you have to be careful is to mark the cams with some red fingernail polish or a white marker of some kind. The be careful is make sure you don't let the chain slip on the crank or your marks will be void.
Remove your cams with a 10mm socket and fold the chain over the front of the motor, do not let it fall in!
Unbolt the head with a 17mm Socket and lift off to put on your work bench.
The engine should look like below now, take a break we are half done.
Ok now take some carburetor cleaner and clean all the surfaces real good. Here is my favorite cheat to do, take an old wire coat hanger and cut it about 16 inches long and bend the tip about 2 inches from the top. You will use this to fish the cam chain back up when you reinstall the head.
Install the head gasket and then reinstall the head while fishing the cam chain with the homemade tool. If you don't you will struggle with it getting stuck and having to take it all apart again to do it this way anyhow. Once you have done that use your favorite Cam Shaft Assembly Lube or if your cheap like me use some White Can Grease. This is done so you don't damage the journals when the engine starts for the first time with no oil up top.
Now reinstall you Cams the same way you took them out and remember the timing marks should look like the pictures above. Reinstall your Cam Chain Cover with the new gasket and some sealer and your done. If you don't clean your motor off regularly it might look like the dirt below when your all done. It took me 8 cans carburetor cleaner and 2 cans engine degreaser to get it all clean.
