I have a 2003 yamaha raptor and the crank is makin some really crazy noise and the local shop told me to get a new crank. On ebay I saw a 720 stroker kit, is that a good idea or not. what should I do or look into doing?
First thing you should do is find out why the shop thinks you need a new crank. I can see some bearings going bad in the crank or the rod breaking but the crank itself is quite durable. If it's gone bad likely that much of the reat of the engine could have been damaged in the process.
Assuming you do need a new crank, yes the stroker kits are a good way to go. I'd go with a vito's/Barker stroker over the hotrods kit becuase of the differences in piston choices but either way it's an upgrade from OEM.
If you're just looking for a cheap replacement you can find stock stroke hotrods crank and rod assemblies for around 250 bucks.