Yup, own several impact wrenches,  both electrical and air.  

Still requires stopping the pulley rotation in a way that can take over 100 ft pounds of impact torque/rotation without damaging belt or rear wheel/spokes or gear clusters.

How did you do it?  

Looking for the different methods to figure out the best one to document.   Would also mention the bad methods and damage that has occurred from using them.

I use an impact wrench now,... 'cause I got one fer' X-Mas...

Before that,.. it was a 1/2" drive 2ft breaker bar with a cheater on the end (about 2ft additional for the cheater)... (PS.. I bent the breaker bar a little... These guys are on tight!)...

Do it in neutral, so's to not damage any gears,... and slide a bar or big wrench across the tops of the swingarm, through the wheel, to stop the back wheel from turning... (can't remember if I get it through the rear pulley or not, but I don't think so... no harm to the wheel yet, and I've done it many dozens of times...)...

The one time I had to do it, it was because the drive belt snapped.  (The belt will not slip over the drive pulley, so, you need to pull the pulley to install a new belt).  As such, the rear wheel was out of the equation.
I bought an impact driver just for this project.  Bike in neutral.  Stuff a bunch of rags in between the pulley and engine case.  And I mean a BUNCH, and wedged tight.  A couple "blaps" with the impact driver, and the nut spun off with minimal pulley movement.
I think it was versy who uses a socket between the pulley and engine case.. but I will let him speak for himself.
If I had heard of that before the rag trick, I would have done that, but with a rag wrapped around the socket.

It was a newbie working with his teen aged son trying to get his engine out of the frame, he started out in neutral but somewhere along the way his gearbox got jarred into gear and the forces jammed up his gearbox/shifter forks to the point he had to split the cases in an attempt to fix it.   Wound up scrapping that engine as I remember, it was several years ago anyway and he bought another bike (non-savage) rather than finish the repairs.






Here is my guesstimation at Verslagen's socket method.   He may loosen the belt some to allow the socket bulge to progress around a bit to hit the gear case itself to help transfer the loading but it will still make a pinch point or "point loading" that will localize whatever damage the impact wrench deals out getting the nut off to a particular small part of the belt.  That one particular tooth is gonna catch some "crush force" fer sure.

A bigger socket and some selective loosening of the belt would give you a good bulged stop point against that screw boss in the gear case.

Also note from this pic the worn in condition of a 7^o side tilt grinder job on the belt.  The belt makes very few and very little squeaks any more and you can see in detail the grind angle and the wear effects over time as the belt "angles in" to a seated position rather than squeaking its way in like a herd of demented mice all the time.  
The 7^o side tilt grinder job just does the sides of the teeth themselves, it does not involve the flat part of the belt at all.









Here is my guesstimation at Serowbot's method.  It uses a steel breaker bar (or other steel bar) to bridge over the top of the swing arm, installed to stop off the ID of the hole in the rear pulley itself and to intentionally miss involving any spokes in the stressed loaded condition.  

NOTE:   for sprocket safety have the steel bar resting against one of the 4 thick spokes, not the little skinny spokes.

There are like 4 places on the wheel where everything lines up to do this, but you have to put the bar in at a slight diagonal to make it work out right.  There is no crush or point loading in this method as the pulleys take the load over their normal seating diameters.




Learned the Hard Way

Electric impact wrenches simply lack the ass to get the nut off, much less put it back on good.   Justin had the skinny on using the air wrench -- short abrupt bursts off a fully run up tank pressure gives the most output torque off the wrench.

OF,... Yup,.. that's it... I just couldn't remember whether I was getting it through the pulley or not...  
You got it ,dude... ...

I haven't done it on this bike, but god knows I've done hundreds similar jobs, I know the best way to do it.
While in neutral simply turn the brake adjuster tight, or have your woman step on the brake while the impact wrench spins it off.
This way there is NOTHING that can get hurt.
If the belt was broke,......a different ball game.
But I believe I could wrap the broken belt around it, vicegrips it,.....whatever, and impact it off. It does not have to be held solid for an impact wrench to spin it off. Even if the pulley was slipping inside my glove, it would still come off,....only slower.

try just pulling the trigger for a second then letting off then doing that over and over till it comes off.


Thats the answer with an impact. The split second when the trigger is pulled is the hardest its gonna hit.,Once it drops the pressure in the hose on the other side of the Milton fitting, hydraulic losses are introduced & a slight drop in power is part of the equation. & if theres a dryer in the line its an obvious loss.,