You don't have to change the 2 stroke oil in the front tank just add to it. Most good synthetic injector or premix oils will be ok. Even walmart oil,Quicksilver,Penzoil if you wish. Synthetics cost more but usually lubricate better and may smoke a little less.No free manuals that I can find any more,but here's a good manual that can help on transmission oil changes and general maintenance and repairs.DOWNLOAD 1996-1998 Polaris ATV Repair Manual ALL MODELS - Download ...

 

Does that one have a counter balance that needs oil like later 400s? I think they're all alike.

 

Holds around 100 ccs of oil in the c/b cavity like the other models.The 400 engine didn't change from 94 until the last year model 2003 Trail Blazer 400.