I bought a tire changer recently (Nomar manual changer), so I've been practicing tire changes on my own bikes. Well my 03 600RR (street bike) needed a new rear tire and I had an extraset of Bridgestone BT-002's so I popped my RR on the stands and went at it. The bike came with a 45 tooth Vortex sprocket but still had the stock chain and front sprocket. Well I happened to notice the part number on the sprocket was the same as on my F4i sprockets. Here is the catch, my F4i has 520 chain and sprockets so... problem. So I get out a set of dial calipers just to be absolutely sure and yep, I've got a 525 chain and a 520 sprocket!

luckily, I had my F4i's stock sprocket in a box of old parts, so I've got a something that will work for now (its 46 tooth which is one tooth larger than the Vortex I took off). Since I've got plenty of 520 rear sprocketsfrom my F4i, I'm just gonna get a new front sprocket and chain (chain needs to be replaced anyway)

so anyway, moral of the story is ALWAYS check sprocket size before ordering, trust me on this, it will destroy a sprocket if you order the wrong size!