A couple of weekends ago my front brake line burst thanks to my poor installation of it causing the front brake rotor to wear a hole in it. I pulled out the stock brake line to fit temporarily but when I went to remove the master cylinder cap the screws were seized. This meant I stuffed up the heads so I tried to drill them out. Clearly I am a poor mechanic as I broke a drill bit in the screw hole. So I was left needing a new front brake master cylinder and a new brake line. The OEM master cylinder was going to set me back a hundred bucks or so

So I went off to eBay to see if I could find a used one from a bike being broken down. What I found was better! A brand new replacement front brake master cylinder with lever and electrical switch for a mere A$28 delivered! I was skeptical as to how good it would be but I have just fitted it and it works beautifully. If anyone is needing one look here: 10mm Front Hydraulic Brake Master Cylinder Right Hand Dirt Bike ATV Quad Bike | eBay
Seller is lesoel_leosel (eBay My World - lesoel_leosel)

FYI, the KLX has a 10mm banjo so you need a master cylinder that takes a 10mm banjo - I don't know what other sizes are available to be honest.

For the replacement braided steel brake line I looked locally in Australia again. The Goodridge I had before I got from the UK but it was a pain to get it here and the first one disappeared. This time I went with a Galfer line - custom green colour for A$65. Again, 10mm banjo fittings and it fits perfectly and has great feel. If you're interested: Galfer Front Stainless Steel Brake Line KIT Kawasaki 2008 10 KLX 250s ALL Colors | eBay
Seller is podiumsuperbikeinc (eBay My World - podiumsuperbikeinc)

 

You probably stuffed the heads of the master cylinder cover screws because what looks like Philips head screws on the KLX (& anything Japanese) are actually JIS which is just different enough that if those screws are at all beyond snug a Philips screwdriver will cause TROUBLE (as you've discovered). Glad it all worked out without being real expensive.