I got tired of my CR5 and sold it wanted to try something different after owning 5 cr500 in the past 10 years. I was liking the fact the K5 has a power valve
So I found a 2000 K5 on craigslist for $2600 too much but it had lots of goodies on it so I looked at it. I found it had a tired top end and shot chain and sprockets and smashed up stock pipe. So I offered $1400 and took it home gave it a new top end new carbon reed petals and torque spacer and new FMF Gnarly and chain and sprockets
this is how she looks now after $1850 in her now

I broke the engine in today wow this thing has a nice broad power band it just keeps pulling for days unlike the CR5 which comes on hard and blows through the gears quick AKA No powervalve The K5 is awesome. I am already looking at 1999 to 2003 KX 250 chassis think I may be doing a conversion
I had a CR 500 AF but hated the vibes in the aluminum I bet this engine in a steel frame KX250 is the ticket I am happy and cant stop grinning when I ride it