should i be worried i changed the oil in my drive and have fuzz on the magnet. there is about 70hrs on the drive.
i change the oil every 15hrs.

I bought a brand new XR last season. When it was taken out of the box, it had fuzz on the magnet.. Jeff Wurl

a little fuzz is normal, the key to look for is chunks where the gear starts pitting.

+1

When i check the fuzz on magnets rub between two fingers if it dissovles like cam lube drive should be ok,if it is chunky good idea to open up drive and inspect gears,after the pits get too deep gears let go making a big mess,always cheaper to replace before explosion

Fuzz comes from two sources.. one is when the net forged gears are new and are breaking in. They give up metal.. ends up as fuzz or powder on the magnet. That should be gone by 25-30hrs.. Good to change the oil often during that time.
The next source is from the thrust washer in the upper pinion bearing stack. It will spin and start to wear. It lets the pinion bearings loose their preload and eventually allows the forward bearing race to dig into the case snout. Too loose and the pinion gear tends to walk and things can fail.
As stated above.. rub the fuzz between your fingers gently and feel for chunks, then look for flakes. Flakes are an early warning sign.. Chunks are a later warning sign. Next is broken gears..
Dick

thank you for the replys.some very good info.