Loosen the alternator rotor bolt.  Hold the rotor with the 36mm wrench and loosen the bolt using a 17mm socket.  I use an impact gun.  Some experts advise against the rattle wrench.  Seems there is concern about damaging the magnets in the rotor.  I have never experienced a problem, but who knows.  You’ll have to decide on your own which tool is best.  The bolt must remain in the crankshaft, don’t remove it completely.  Just back it off several turns so that there is at least a ¼” gap between the rotor and the bolt flange.

Remove the rotor using the special rotor puller.  Lubricate the jack bolt threads and tip before installing the tool on the rotor.  Thread the tool onto the M50 x 1.5 threads on the rotor, then install the jack bolt and screw it in until it touches the alternator rotor bolt.  You must be sure the tool is completely threaded onto the rotor before you install the jack bolt.  Back the body of the tool off about one-quarter turn, then hold the tool with a large crescent wrench while you turn the jack bolt in (clockwise).   It takes quite a bit of force to pop the rotor off the crankshaft taper.

The key fits tight in the keyway.  You have to break it loose.  Wrap the key with tape so you don’t loose it.  Then lightly drive the key straight in with a punch, as shown.  Use very light force, keep the punch off the crankshaft taper.  Tap just hard enough to move the key.

The taper is critical.  Don’t damage it.  Keep it looking like this, free of blemishes.

Install the special flywheel holder on the flywheel.  The two 8mm bolts screw into the tapped holes in the flywheel.

Remove the flywheel nut.  There is a Belleville washer between the nut and the flywheel.  The washer outside diameter edge goes against the flywheel.  The inside diameter edge goes against the nut.  Make sure it is oriented correctly when you reinstall the washer.

Ready for reassembly.  The new flywheel doesn’t take up much room.

How does it run?  Just fine.  Starts right up, idles smooth, revs about the same.  With the gearbox in neutral, snap the throttle open and everything seems the same as it was.  Vibration levels feel about the same.  Noise is the same.  Clutch action seems about the same, might take a little more finesse to get underway.  Very surprising, you would think this thing would really snap, but there’s no perceptible difference.

Time for some acceleration tests.

Let’s look at the setup.  Stock engine with DR 650 cam and 3” flywheel, stock cylinder head, stock piston, stock bore & stroke, stock compression ratio (8.5:1), modified airbox with K&N RD-0710 cylindrical filter element, PWK38 carb, stock exhaust header, LCGP high flow muffler.
 
The flywheel isn’t going to affect air/fuel ratio, so I left the jetting as-is, a #35 pilot jet, #145 main jet, and the needle clip in the fourth groove (rich).

Second Gear 4K to 7K: 2.92 seconds            0.05 seconds faster than stock flywheel (a wash)

Third Gear 4K to 6.5K: 5.13 seconds            0.11 seconds faster than stock flywheel

Third Gear 4K to 7K: 7.53 seconds            0.12 seconds faster than stock flywheel

Fifth Gear 3.5K to 5K: 5.04 seconds            0.02 seconds slower than stock flywheel (a wash)

Fifth Gear 3.5K to 5.5K: 7.96 seconds      0.21 seconds slower than stock flywheel