You do not have to remove the swing arm to change out the driveshaft.
You will have to do the following:
1) Remove the rear tire and shocks.
2) Remove the final drive unit by removing the 4 nuts.
3) Slide the drive unit out. The drive shaft will come out with the drive unit.
4) Remove the rear brake reservoir and bracket to gain access to the U-Joint boot.
5) Pop the boot off the motor and swing-arm and remove from the bike.
6) With the swing arm in the down position, thread the U-Joint out.
Installing the new U-Joint is the reverse. One gotcha though, lube the boot with a little grease, WD-40, or similar slippery substance to aid putting it back on.
Another gotcha, don't tighten the drive unit bolts until after you put the tire back on and tightened (not necessarily torqued). This will help align the drive unit with the wheel so you don't put the rear end in a bind.
Hope this helps.
Joe
P.S. Found this after I typed all this in...
http://www.rattlebars.com/mtz/ujoint.html Note: If you remove the shocks, you do not need to remove the exhausts. You can lift the wheel up to slide the axle out.
