Damn, is this a hard forum area to get a solid recommendation, LOL.

So, I've got Mobil1 20W-50 to go in my '16 FLHTK. Going to to do primary and tranny too. I've read that the M1 product can be used in all three holes. However, HD has new 80-140 Heavy Duty Syn Gear oil. So my question, Does Mobil1 make a product that compares with the new HD 80W140? If HD is suggesting this, I would imagine there is a reason, and hopefully not just marketing etc., and trying to make $$.

Is there a better M1 product for the primary too other than the 20W50. I'd like to stick with the same brand for all three holes, but want the best product designed for that specific application.

 

What`s the best color for a Telecaster?
What`s the best flavor Ice Cream?

 

Pick your poison. Many companies offer quality oil products for all 3 holes i.e. Amsoil, Bel-Ray, Motul etc. I use Spectro Oil Products myself.

https://spectro-oils.com/products/

 

M1 75-140 gear lube in my trans. Slick stuff, smooth shifts.

 

I just ordered this kit. Showed up the next day. Awesome reviews. Some reviews even said it was better than Amsoil. I was sceptical not knowing the brand but resarch shows its a great oil company

 

The gear lube and primary lube in that kit are dino oil, not synthetic. Fine, if that's what you want.

 

Mobile v-twin 20w50 crank case. mobil 1 racing 4t 10w-40 motorcycle oil Primary, Red Line Severe gear in Transmission.
Any combination with those specs with the oil you are comfortable with will work. 40% oil 60% peace of mind.

 

This is a hard place to get solid answers because the questions are vague. Almost everyone waaaayyyyy overthinks oil.

- There is nothing wrong with using Mobil 1 V-Twin in all 3 holes.
- An approximate equivalent oil to HDs new gear oil would be Mobil1 Synthetic Gear 75W-140. This would be just fine in your trans.
- Almost certainly the HD HD gear oil 80W-140 will be JASO rated to be clutch safe. HD generally won't put these things on the bottle but rather tell you what they are recommended for. Mobil1 makes no such assertion for their gear oil so it's use in the primary may be somewhat sketchy. Likely you will have no issues with it, and it will be fine with the clutch, but I cannot make a definite assertion to that point. Mobil1 does not have a primary specific oil. Clearly they feel such in unnecessary as their V-twin fills the need. Amsoil only just recently released a primary specific oil, not because it is needed, but because customers kept asking for it.

It's important to remember, in all of this, HD only just released a gear oil for the trans / primary. People have been riding their bikes for years with Mobil1 V-Twin in all 3 cases without issue. There is no need to begin a hunt for something better if you are satisfied with what you have. Mobil1 is top shelf oil and the likelihood of ever having an oil brand / type related failure while using Mobil1 V-Twin is so remote as to be non-existent.

 

Same here, been using this combo for years.