Before you guys hang me, I tried using the search tool to do research and everything under the sun just comes up in reference to this... I want some straight forward up to date answers from the gear monkeys that you are..

I live in Maryland where the summers are hot and very humid. My 48 (sportster 1200) is coming up on its 5000 mile oil change, also going to change the Primary oil while im at it. First oil change at 1000 miles, Syn3 was put in it and i just feel like theres better oil out there...

1. Which motor oil do YOU recommend for this hot and humid state?
2. Thinking about Redline for the primary, but which kind?

Pic for attention.

 

ready

 

Use the slippery stuff.

 

I use m1 15w50 in crankcase and formula + in primary. Change both at 3k mile intervals

 

3 thousand miles?
I go 9 to 10 thousand.
All good tho

 

Motul 20/50 full synthetic harley spec in both holes

Like those bars how do you extend the electrics

 

Syn 3 in engine, formula + in primary/tranny.
I live in Florida hot and humid the majority of the year. Can't go wrong with synthetic in the engine. Formula + has always worked for me in primary/tranny

That said it's a personal choice!!!!!! Everyone has an opinion on this subject. It is the pre-verbial can of worms.

 

Red Line recommends the 75w-90 diff lube for the current Sportster Primary/Transmission.

You could also use the Red Line 75w-90NS (without the limited slip friction modifier)
You could use the MT-90 manual transmission fluid.
You could use the 75w-110 diff lube, it is very close to the viscosity of HD Formula+.

I would suggest you not consider any of the "Shockproof" Red Line Lubes for the Sportster primary/transmissions. They do not work well with the clutch in the HD shared primary/trans of the Sportster but do work well in the Big Twin separate transmission.

 

I use Red Line 20W50 synthetic in the engine and Red Line 75W 90 GL5 gear oil in the trans.
Parrothead on the other forum has 206,000 miles using Harley SYN3 in the engine and Formula + in the trans so what can I say.

 

you get a pass on this one cus MD, selflessness, and fire trucks.

mobil 1 synthetic 20w-50 or hd synthetic 20w-50 are that go in mine. i used hd dino 20w-50 one and the bike noticeably ran hot otter and made more top end noise

K&N KN-171 (B or C) filters awesome and easy AF to get off, i refused them for years and feel stupid for it


don't waste time on oil. It's silly and that's why you are getting the "c'mon bro" type responses