Harley Davidson Softail Oil


Gday all.

Oil question…. Yup that question haha. Heard that Lucas oil is the go and to stay away from synthetic oils for a 103 motor due to bore glazing and early failure. Got this info from a mechanic that has done many harley rebuilds over the years (about 30 years) and has seen the damage first hand.

Question is i got myself a 20w50 for the motor and gearbox however went with the Lucas primary oil. With the primary oil do i just use this straight in the primary or mix it with the 20w 50. Know it’s a strange question but it says on the rear of the bottle it’s not a lubricant which seems a bit miss leading haha.

Anyone know what the go is?

Daniel 5 years 6 Answers 690 views 0

Answers ( 6 )

  1. Primary Oil goes straight in.
    Oil goes in Oil
    And probably change your transmission while your at it.

  2. Cool cheers mate, had me thrown by the (this is not oil) written on the back of the primary bottle haha. Using the 20w50 for the motor and gearbox

  3. I run nothing but Lucas synthetic products in my Fatboy, love their products! Good choice!

  4. Who ever told you syn oil will damage your motor is an idiot.

  5. Lol, he is actually a mechanic in his late 50s that’s been working on Harley’s his whole life and looks after a whole club. I’m inclined to listen to him after seeing damaged bores from glazing and clutches that burn out before their due. Showed me while i was in the workshop last. \n\nGotta ask the question why so many high k Harley’s that ran on dino oil are still about where as newer Harley’s with fewer ks are doing rings, cylanders, scoring and glazing ect. Most new bikes are running synth ;).

  6. Mobil 1 20w50… motor trans and primary

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