Maybe this subject has been covered in different ways, but I'm hitting it anyway. My '07 Exmark has a Kawasaki FH580V engine that began showing signs of needing a valve adjustment by making a 'clicking' noise and declining power. After acquiring the manual online, I read over the procedure and decided I know a better and more precise way of making this adjustment. I used a piston-stop bolt from Summit Racing, and a homemade degree wheel made out of a simple paper picnic plate, some duct tape, a fine tipped marker, dial caliper, and the right tools...plus a set of replacement valve cover gaskets. Took me about 4 hours to do the job, mainly because of meticuously cleaning the old gasket material off without damaging the mating surfaces for the new gaskets so that oil wouldn't leak. The actual adjustment time was only about 30 minutes per cylinder. The result; the engine has like-new power.....is now very quiet and smooth...starts easier with little choke and will idle smoothly even if I turn the choke off right after starting even if it's 30 degrees outside. It didn't run this good when brand new. The manual says to use a flat spot on the coil pick-up as the TDC reference but using the piston stop and degree wheel is much more precise....in my opinion. This is probably the most overlooked and/or avoided maintenace task on any engine, espeically mowers/tiller/generators/...etc. If you perform this task after about 70 to 80 hours of operation, you can probably then extend the hours to about 200 after that because of the break-in period. If you are not knowledgable about how a 4-stroke engine works, don't try this yourself or you could destroy your engine by not understanding about how to set your engine at TDC(Top Dead Center of compression)....not knowing how to have that 'feel' using a feeler gauge. We're talking ONE THOUSANDTH'S of an inch measurements here. If you set the lash too tight, you run the risk of a valve not closing completely thereby allowing either air/fuel not being contained in the combustion chamber, or..exhaust gases flowing backward into the intake. I'm saying that these are PRECISE measurements and you should have a good working knowledge of how a 4-stroke works. This engine was fairly simple to work on as I have experience with 4-stroke motocross engine tuning. The FH580V engine utilizes a simple 2-valve per cylinder/pushrod configuration with manual rocker style lifters. This is about as simple as it gets. Hope this helps someone. BTW...set valve lash at .004" intake and .006" exhaust. The exhaust lash is larger because it runs hotter and the metal expands more than the intake. The intake runs so much cooler because of not only the air/fuel mixture entering, but because of the intake vacumn.