M6 socket screw with T40 head?
 

I'm trying to fit a magnetic speed sensor for a digital speedo to the back wheel of my '97 XT600. I would like to replace the M6 hex bolts that hold the back brake disc in place with M6 socket screws that have a head with a torx or allen key fitting big enough (T40) to accommodate the 6mm diameter sensor magnets. Does anyone know if these are available? (I have tried fitting the sensor to the front wheel but there doesn't seem to be any way to fix it in the right position).

That will be difficult

Another way?

Make a bit of metal that bolts to 2 of the standard disk bolts ... and then mount your magnet to the bit of metal - keeps the standard disk bolts.

Great idea! Thanks Warin. That's a much easier way of doing it.

Some people epoxy the magnet disc in a corner of the front disc, the magnet basically holds itself and the epoxy confirms it won't move . I've always just used the magnet tipped disc bolts and made mounts one way or another for the sensor, has always been possible. Lots of way to mount those sensors and various sensor shapes so I like to look into another sensor that may fit better for my particular application.

I always buy a small neodymium magnet. They're much more powerful than the ones that often come with the kits.

Rough up the disc where you want to place it and dab on some Araldite epoxy resin to further secure it.

You'll need a chisel and hammer to remove it.