Being the old persnickety coot that I am, checking and adjusting the valves on my Kawasaki FH580V v-twin has become a routine maintenance task that I actually look forward to performing usually in late October when it's cool outside. The specs are for .004" to .006" on all 4 valves. I've been setting the lash at EXACTLY .004" gap on all the valves for the reason of taking advantage of the maximum lift and duration of the cam lobe profiles thereby allowing maximum power output, plus, I find that this makes the engine mechanically very quiet with quick reliable starting. If it's hot outside, the engine will even start without the choke. It's a 2007 engine on an Exmark with 548 hours of hard usage. I do some repair mower work on the side and I have noticed that so far, every machine I've worked on had never had the valve lash checked. One relative brought me his 3 year old Craftsman lawn tractor with a B&S 24HP V-twin for me to replace both belts. After replacing the belts, I wanted to do a quick test to make sure everything was correct and the engine was hard to start and idled poorly once up to temperature. Without telling him, I checked the lash and found all the valves were out of spec, some worse that others. The lash specs are exactly the same as my Kawasaki so I set all valves at exactly .004" and the engine's issues were completely resolved. When he came to pick of the machine, I deliberately did not mention the valve adjustment. About 3 days later he called me and asked why changing the belts has such a profound affect on making his engine run like new, BETTER THAN NEW. When I told him that I had adjusted the valves, he admitted that he didn't know valves needed adjusting. That seems to be the norm.