My latest vehicle purchase ( a 2005 Kawasaki EX250 motorcycle) is once more reaffirming the rule of thumb that any used vehicle I buy will incur in the first two months of ownership, maintenance and repair costs greater than or equal to the purchase cost of the vehicle. In this case, the guy who sold me the bike had done his own valve adjustment a few months earlier. He apparently badly botched it, ruining the valves and valve seats (one cylinder had zero compression). Then offloaded the bike to me, saying that it ran rough because the carbs needed cleaning and it needed a $10 mixture screw. Sigh.