Yup standard bit. Make sure you don't punch through anything on the other side that you don't want to.

Make sure the drill bit is sharp. Otherwise it will heat up and melt the plastic as you're drilling through.

Run the drill at low speed. You'll get a cleaner hole that way.

I use a step bit
I find they drill a perfect round hole and dont tend to grab like a standard bit

+1 They aren't cheap, but they make a much nicer hole, and aren't nearly as prone to cracking plastic.

as opposed to fairing plastics, you don't have to worry about the fender cracking or breaking. the plastic is quite pliable and very tough....which it has to be too stand up to rocks and road debris that might get kicked up by your tire.

with that said....go at it with whatever you have that will poke a hole through it. definitely don't waste your money on an expensive new drill bit. if all you have is a rusty old dull one, then use that. you can always clean up the edges with a sharp knife if you have to. basically, just do whatever it takes. aside from trying to poke a hole through it with a jack hammer, it is very unlikely you will be able to crack or break anything. and if the drill is dull and just heats up, well so be it....still ain't going to hurt anything. as long as you get the hole you want. with due respect to the others who posted advice, it is not as nearly as complicated or "fussy" of a job as they make it sound. I would suggest following Chris's advice though....just watch you don't drill through something you don't want to drill through.

I would suggest sticking a rubber grommet in the hole if you have one. if not, silicone the hole and around wire to keep water from getting through.

disclaimer: the preceding advice is based on the assumption that the 600 and 750 kats use the same basic pliable abs plastic found on every other bike fender out there. if by some chance the 600 and 750 kats are unique and use fenders made up of a different material, I am not responsible if my advice leaves you with a cracked fender. I am 99.999999999% they are the same as the fenders on the 1100 kats, which I am familiar with, but I will still use this disclaimer to cover my azz. :

Good point about the grommet, it's always nice not to have the plastic cut through the wire's insulation

yes, that is another thing. and kudos to you for catching that.

I got a "sale" on a set of three in case for less than $20
Didnt need them when I bought them but I still bought them

even on sale, $20 is too much for drilling a hole in a fender. hell, for $5 I will do it with an old manual drill and a wood bit. :

Like I said , bought on sale
I had used them before for work
A great addition to a tool box

actually they are handy to have. it's not every day that you need them, but they pay for themselves the first time you really do.

Thanks guys just used a standard bit it worked fine. Quite prowd of my wireing and will post picks. But right now bike wont IDLE properly. So i need to get that fixed