Re: Tools. What is absolutely necessary?
It really depends... if it's a small kit to keep with you while riding, a small tool bag, a set of screwdrivers, a folding allen wrench set (metric) small needle nose pliers, small slipjoint pliers, 4" vise grips, metric wrenches: 8, 10, 12, and 14mm, a handful of 6" zip ties, a small fix a flat kit, and a small tire pump. Everything should fit in this bag and the bag should be big enough to fit the tools you're carrying but not much bigger.
This is enough tools to get ya out of a bind and back on the road if something goes south and you're stuck in the middle of nowhere so you can ride home instead of pushing the bike home. If one plans on a longer trip, I'd add in some spare parts like a spare mag coil, spare cdi, about 6 feet of 14 gauge wire, some wire splices, a small container with enough 2 cycle oil to mix up a gallon of gas, a small can of WD40, an extra spark plug, extra hardware, an extra inner tube, more zip ties, and a small led flashlight. Basically just enough stuff in case you take a spill and crack a spark plug or all your gas drains out from being tipped over and you're 10 miles away from home etc... This is for those "do what you can to get it running" fixes to get ya home where you can do proper repairs.
This doesn't even come close to the tools to have at home...