Wheres the drain plug for a 1989 harley davidson sportster 883

SOURCE: oil drain plug

Follow the hose that goes to the frame from the oil tank. Loosen the clamp and pull.

SOURCE: I have Harley Davidson 2000 Sportster 883. I

Neg cable corroded thru.
I bet you have 12v at the battery and less at the other end of the neg cable.
I had the same problem.

SOURCE: Throttle to engine problem on 1993 Harley 883 Sportster

 You either need to lube the cables, or adjust them. You adjust the throttle to have a 16th to an 8th inch of freeplay with the bars like youre riding straight. You adjust the snap back with the bars fully to the right. As far as the motor shutting off , you need to use the enrichner ( they call it a choke) until it will idle on its own without rapping the throttle.  Also , your idle may be set too low on the carb. The adjustment is made at the idle speed screw , right behind the air cleaner. 

SOURCE: how to set the timing for a 2003 883 harley

there is is no timing after static or set up timeing your ignition module controls timing and advance

SOURCE: where is oil drain plug on Harlry Davidson 1995

Bottom infron of centre kick stand