I have a 250sx 85 clocked it at 55mph
Factory plug is NGK DR8ES-L
On the bottom side of the cases either in the center or at the back (towards the rear wheel side of cases).
Start the bike up and ride it or let it idle for a few minutes to war the oil up in the engine. Then kill the engine and loosen the drain plug on the bottom of the engine. Let all of the oil drain out and replace and tighten (careful to not overtighten) the drain plug. Remove the filler plug and add your oil.
If you mean the oil drain bolt it is on the left side on the bottom of the engine its a big bult when it comes out there will be a spring and oil filter
Drain the old and add the new...use SAE 10-40
13 ounces
50/1
Eng oil capacity 1985 Honda 200 m atc?
using to much oil in the gas
Motorex, SAE 15W-50
09 250sx has 47 hp