Royal Purple is the best stuff out there. I use it in all my cars and both bikes. Their gear oil for the cars makes them run significantly quieter. I would not trust any papers from Amway, . . uhh Amsoil, they taint everything toward themselves with no objectivity.


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http://shop.advanceautoparts.com/web...ci_sku=8070004

8.99 qt ITS WORTH A TRY YOU WONT GO BACK.

 

But the motorcycle oil is $15.19 a qt.
http://shop.advanceautoparts.com/web...T|GRP2046_____

 

bah, who cares? it's 20/50. you don't have to use 'motorcycle' specific oil in your harley. your primary and engine do not share the same oil, so you don't have to worry about friction modifiers making your clutch slip.

mobil1 15/50. used to get it from walmart for 23.00 for 5 qts (some reports say that it may be coming back ) but you can find it for 5 or 6 bucks a qt at autozone, napa, etc....

 

Motorcycle oil has more ZDDP. Very important. Was in car oil "forever" until they found out that it ruins catalitic converters, so now most car oils don't have it anymore or very little. It is still in motorcycle and diesel oil. If you are interested Google ZDDP. It is all over the web. The muscle car guys all look for it. Your bike needs it.

Now, from another perspective. . . . . . All synthetic motor oil nowadays is so good that you could get away with running car oil with minimal ZDDP in your bike. It's like feeding your three year old son nothing but Cheerios and M&Ms. Would he survive? . . . Probably, but why not give him what he needs?


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i did research it. the epa is making oil manufacturers lessen the amount of zddp in the 'fuel efficient' oils (ie 5w-20), which the higher viscosity oils like mobil1 15w-50 is definitely not in that category. however, there are additional friction modifiers in it that may actually be better for your engine than the vtwin stuff. the big sell for the vtwin stuff is that it doesn't have those friction modifiers in it so you can use it in your primary. well, since hd uses a separate sump for engine and primary, you can safely use the automotive oil in it. it will have sufficient zddp in it for our engines.

besides, if zddp is bad for catalytic converters, shouldn't we stop using it now that all touring bikes come with converters?

 

I was running Royal Purple, then my primary bearing went bad, so not taking any chances, I switched the primary back to Formula+, and Mobil 1 in the others. Never did see anything better running Purple.

 

..........and the "GREAT OIL DEBATE" lives on.

 

+1 I only use oil approved by N.A.S.A. that is able to cool down nuclear reactor melt downs, because off the shelf Castrol, or Mobil One will never be able to cool my engine as I race along at 70 m.p.h. and take hair pin curves on country roads at 45. Royal Purple is aptly named, kind of like the kool aid.

 

now that obama has all but cancelled the space program, you should be able to get that nasa oil at a huge discount!