I just changed oil in my 1977 XLCH Sportster (kick start). I emptied tank, then screwed on plug & filled about 1/4 with kerosene, shook bike a bit & drained thoroughly. Then refilled with 20-50 harley oil. Was this correct way. I pitched bike to drain all kerosene out of tank, but worried about residual kerosene. Also, no oil filter. DidnĀ“t they originally have one?