My technique was to put it in neutral, get the front tire up against the wall, stand on the brake, get the breaker bar in a horizontal position forward of the nut, pull up and grunt like hell.

 

Correct. NGK even warns on their website not to overtorque spark plugs when using anti-sieze. And I second the cheap Harbor Freight impact wrench idea. There's no way I could have got the sprocket off my Wee-Strom without one.

I'll be using it on the KLX soon as well.

 

That's one tough nut to bust!

 

Or $40 depending on current "sale". Either way it is well worth it for this and things like fork bolts that need thousands of tiny hits to break loose.

 

A little well-placed heat goes a long way too.

 

Borrow the tool.
You'll only need it that one time on the bike.
Well maybe twice, if you ever need to loosen the engine mount bolts.

 

Did the front sprocket on my WR250F last weekend and needed the air impact wrench/gun.

Was looking fairly impossible without it!