Remove them with some WD-40 and some vice grips.
3 turns out..
Use a socket wrench. Mine are stripped too (that is the Phillips screwdriver part). but a socket will work
To adjust the carburetor on a Yamaha badger is really simple. There will be two screws one is a slotted head and the other is a four way. To adjust the carburetor you have to turn the screws clockwise until the engine idles fast.
Good luck removing a stripped screw from plastic. There are ways, but I'm not going to discuss because you'll probably burn your house down.
The seat on a Yamaha BW80 motorcycle is removed by taking out the retaining screws under the lip of the seat. It can then be raised up and detached from the hinges.
You could use larger screws.
Hopefully you stopped once you realized it was stripped. If you did then your best option is to use a T7 driver and first tighten it (turn it clockwise) so that it can grab onto the un-stripped portion of the head. Then turn it (anti-clockwise) to loosen. Hope this helps. I tried this on my stripped screw on the Juliets and it worked. If it is stripped real bad and you went at it a few times then ideal would be to walk into an optical store and see if they can do it for you. cheers!
(2) 10mm screws on the front of the motor. Tke them out and pull out starter, disconnect wire.
There are three screws that go into the door and affect the lock. These may have been stripped and fallen out. Just needs new screws.
You need to re-bore the existing holes or drill new holes. :) Simplest solution: Use self-threading screws slightly larger than the original screws.
The Yamaha 250 series of motorcycles has the oil filter on the right hand side of the motor, and between the two cylinders. There will be plate with three screws that says "Yamaha" on it. Once the cover is removed you will have access to the oil filter which can be removed and replaced manually.
the Yamaha symbol underneath your headlight is your fuse box, remove the two screws and there they are. there are also some relays underneath your seat if you havn't already found those.