Not to be rude, but there are quite a few things that need to be torqued to spec with this application. You can find a manual online that outlines everything you need to know. You'd likely have your answer in much less time than it takes to post a question here again.
A stock exhaust with the baffles still in it should do the trick.
The Yamaha Warrior 350 is a 4 stroke.
if the 87 is a warrior yes
No, Yamaha only made the Yamaha Warrior 350, nothing else.
a 2009 Yamaha warrior weighs in at 396lbs
A Yamaha Warrior has a horsepower of 350. The Yamaha Warrior is an off-road all terrain vehicle and has been around since the 1980s.
Yamaha stopped making the Warrior in 2004.
No, the plugs are different.
yes the crankshafts are the same
what are the torque specs on a 1989 yamaha 350 quad
No, you can not.
Yes It will but you have to use motor mounts off of the warrior