still confused about primary fluid?

[Bud White]

you will get many different opinions on oil

i run 15w50 mobile 1
75-140 lucas non syth trans fluid shifting is better than with spectro as hard as that is to believe
and valvoline 20w50 motorcycle oil in primary designed for superior wet clutch protection

 

[Buster]

With any lubricant post you'll get a lot of different answers about what everybody uses with success for them. For me, I use only HD plus in all customers bikes without a failure ever. I don't tend to follow all HDs recommendations on lubricants but the + has worked for me so I'll stick with it without experimenting with something that may fail in a customers bike. Plus, if a product cost more, I want to see proof that it does something to warrent the additional cost.

 

[glider]

Plus, if a product cost more, I want to see proof that it does something to warrent the additional cost.

That's about the same as saying that "it works for me"

How about better shifting or less gear noise as proof?

 

[TQuentin1]

Just so I don't mislead talking 2 Bikes here .. My 04 Sporty which a Buddy now owns that has over 60K now still trouble free using Amsoil 20W50 for all .. And my 01 which had 8,000 on it when bought, first Oil Change put Amsoil 20W50 for all and now at 40K Has never seen any down time due to Engine or Tranny problems..

Engine oil in the engine is good (as long as it is a full synthetic 20W-50 vtwin oil). But there are better alternatives to engine oil for the tranny and the primary.

Tranny: Full synthetic, GL-5, 75W-90 or 75W-140 gear lube.
Primary: Fit-for-purpose chaincase lube for use with wet clutch (like HD Formula + or Spectro Primary).

TQ

 

[Jack Klarich]

I would strongly disagree with using auto trans fluid in your primary.
It is not and automatic tranmission not even close to one.
HD F+ will work fine so would Spectro primary oil or any of the for that madder.
I know many say not to use SYN in primary I have and do in one of my rides with no problems yet.

I agree, ATF is great for power steering pumps and automatic transmisions, I even use it in hydraulic jacks, but not on my bike. It is a hydraulic fluid

 

[harleypr]

I don't get why most on this site use 75W140. I've run 75W90 for 20 years with no trouble but we don't get a lot of days over 85 degree's. I can see it if you live in the south where you get lot of HOT day's but in the north I just think 75W140 is too thick for 40 degree weather. JMHO

It's important to understand what the numbers mean. I think there is some confusion here. If you have a 75-90 and 75-140 oil they should both start out with the same viscosity at the lower temperature. As temperature and stress both cause the oil temperature to rise then the viscosity improvers in the additive package will cause the oil to thicken to provide a greater level of protection. As an example, if you shake two containers of oil with the same lower number then heat these containers to 200 degrees then you will feel a viscosity difference with the oil with the larger 2nd number. The companies add more improvers to allow the oil to cushion and quiet the component parts at elevated temperatures. The advantage of the 75-140 is more evident at elevated temperatures and it accounts for all the reports of why Spectro 75-140 is superior, or any comparable oil also. Ask yourself why 15-40 or 20-40 oil is preferred in cold climates for engines. It's because they don't increase in viscosity as much as 20-50.

 

[NEWHD74FAN]

Great oil debate on primary fluid...if you are really concerned about what fluid to put in, consider oils that are not 100% Synthetics because they have friction modifier additives which will damage the clutch. I would use HD Formula + OR an MA JASO approved motorcycle oil (if thinner oil is your plan) as they are made for Metric sportbikes where everything is lubed via one oill...Engine, Trans, Chain and Cluth...how UGLY is that? :newsmile040:

ATF Automatic Transmission Fluid was not made for lubricating primary chain or be slung all over the interior of as it is pretty thin (a specialized hydraulic fluid made to pass through the shifting throttle body with very tight tolerances). Some are Ethylene Glycol based which is designed to swell seals a bit as well, but likely at a different rate than petroleum based gear lubes. Your ride, you decide...! :s