Okay guys, recently bought a 76 Harley SS 250 low mileage second owner, the back has set for 25 years I get it home and drop all of the old oil and flush the motor numerous times until finally clean. I´m ready to fill the back back up with 20w50. So after I fill up the oil in frame reservoir how much do I add to the crankcase??? Also can anyone tell me the spark plug gap along with any other tips and tricks you guys may know, thanks in advance much appreciated