On the very top of the engine... and not easy to get to must pull off side cover to access also use tools that came in kit with bike they are the correct length to get at it
its inside the exhaust
0.070
BKR6E plug with 0.035 gap.
Sportsman 400 4x4 94-97 .028 NGKBR8ES
To change a spark plug you need to take off the seat and the side panel on the right side. After you do this the spark plug will be in front of the carb and on top of the engine block.
On top of the cylinder head directly under the fuel tank.
Just changed a plug this AM. Remove the right side panel. On top of the cylinder (top of engine) there is an orange or red rubber plug. Spark Plug is under this waterproof plug. Need a 5/8" spark plug socket and about a 3 inch extention to remove plug. Kind of a pain to get to. Tight area to work in. Good Luck!
Take the seat off , then the right side cover . The spark plug will be behind the ground cable on top of the motor . Should be a special spark plug tool in your tool kit .
the spark plug is located directly under the gas tank, If you pull off the left side pannel you wlll be able to see the wire.
buy the owners manual, the sportsman 600 & 700 should use rc7yc and they should be gaped at .035" (.90 mm)
if its water cooled you have water in the oil ie; head gasket or liner leaking.
on top up engine. below fuel tank. usually has red rubber cover.