2010 Harley-Davidson Road King Classic

The first 2010 FLHRC review

Oil, Oil, Oil

with one comment

Hello! Long time.  Hope everyone’s well!  I have been getting a few hundred page views a day, so I figure I better feed the animals.

First up, I am never going to make that post about installing header pipes.  All I have to say is to remember to change your head gasket.  Be gentle getting it out and use lube to get it in.  Michael Scott to the white courtesy phone, please.

Next, I have been continuing on with the oil research game and I wanted to present my notes to anyone else in the situation I was in not too long ago.  That’s what the rest of this will be about, so if you aren’t here for the oil discussion, then I wish you safe rides and please continue to message/comment if you have questions – I still get the comments and will reply by email or by reply post.  I say this in case it’s another few months before I post again ^_^



Here’s my short answer for anyone googling for what to use to change the oil in their 2010 harley davidson touring bike (road king, road king classic, electra glide, street glide, or ultra glide): 20W50. Put in 2.5 quarts and adjust the level slowly if more is needed. Don’t buy the cheap stuff, buy a brand you’ve heard of before.

We’ll talk about that in detail below.

The dino v synthetic dispute will never end.  Let me just say that for motorcycles, it’s a different ball game than for cars or trucks.  Yes, they’re internal combustion engines, but no, they are not identical in terms of needs.

Let’s take the pieces one by one.


20W50 is the best weight oil to use in your 96-cubic-inch air-cooled 45-degree V Twin if there’s no snow on the ground.

This is a summer-ish blend which will protect your bike in ambient temperatures up to 96 degrees.  If it’s hotter than that, on your ’10 tourer you will need to switch into parade mode (rock the throttle forward to kill one of the pistons).  Or better yet: don’t ride! 96 is good weather to hit the beach until sundown.  If you live someplace where it’s that warm, you need different oil and you need to not listen to me.

20W50 is also good down to about 30 degrees, so again, don’t run this weight if you are in a place too cold: see above, ignore me.

Now if you’re in the standard north american climate, 20W50 will do you right.  It’s a thick-film oil that will keep your bike’s guts sloshing around nice and pretty.  No grinding, no damage, just smooth-as-butter operation.  This is what you want, a thick oil to withstand all the heat that will build up on your air-cooled ride.  Long stop lights and blistering pavement will make you happy you used the hearty stuff.

10W40 has often been the common choice – maybe that’s just a hold over from what you’d put in your car.  10W40 is inappropriate for motorcycles as bikes have a wet clutch – the engine oil flows through the transmission.  The problem is that the stress of shifting is much worse than the regular stress of circulating in a hot engine.

Oil is made of “stuff” (can get into it later) and that stuff will break down under too much stress.  10W40 is fine to use in a regular, non-wet-clutch engine, because it will keep its integrity up to a few hundred degrees (normal operating temperatures within the cylinders).  When you start running oil through the clutch, the oil then has to deal with extreme pressure.  10W40 cannot cut it. It thins out and you’ll get grinding.  You will know your oil is unsuitable if, when changing it, it is significantly darker than it was going in OR, worse, if you can detect metal fillings in the oil.  That means you’re grinding up your gears and you will start to experience slippage and ultimately a dead transmission unless you can identify the problem.  Using the right oil is the first step.

15w50 is also sufficient and at times preferred – such as if you have mornings that are in the 20’s but afternoons in the 70’s (which could be anywhere with the way the planet’s climate has been these last few years).

I’m not making this stuff up.  20W50, or 15W50, are both measures of different types of “additives” and the same type of oil.  The first number is low-temp viscosity and the second number is high-temp viscosity.  Note that for both of my recommendations above, the high-temp viscosity is 50 SAE.  Again, a thicker, high-viscosity oil is better for the hard life of an air-cooled V twin. The first number applies to the engine when it’s been sitting (off).  If you have a 20-degree morning and your bike’s been sitting, the lower your low-temp viscosity number, the better.  Unfortunately, the lower it goes, the more frequently you have to change your oil as the lower its viscosity the more easily it breaks down.

Now let’s talk about those additives.

Synthetic vs Fossil/Dino/Organic

What would you say if I told you that many “synthetic” oils are not man-made? It’s true.  Amsoil is one of the only truly lab-created synthetic motor oils.  It works like a charm, and it’s not much more costly than the other synthetics.  Is it better? Yes.  Do you need it? No.  Or, to be more precise, no you don’t need it unless your engine is old and you want to ensure the maximum life out of it.  Thanks to a court case from about 10 years ago, the word “synthetic” is a marketing term and does not require an absence of organic bases.  So what’s the difference?

Ask a scientist.  I’m only interested in the short answer and I hope that will suffice.

Other than Amsoil, when you buy a “synthetic” oil you are actually buying a highly-reformed dinosaur oil.  It’s pulled from the earth and broken into all its pieces.  Then they save the “stuff” that works best in engines and add some “stuff” that makes up for what they took out.  What they add is generally superior to regularly-refined dinosaur oil.  It can help your engine stay cooler and run more smoothly, plus it’s cheaper to make than pure synthetics like Amsoil.  It’s win-win.

So what is regular dinosaur oil? Petroleum and wax.  Seriously.  Synthetics were invented by the Air Force during WWII to help those badass newfangled radial engines from blowing themselves up.  Not to get into molecular chemistry, but the “base” of the oil, the “stuff” that oil is made of, is classified by a Group.  The Group II oils are petroleum and wax (literally paraffin); Group III are petroleum with newer, better additives.  As such, any Group III dino oil is roughly the same as a pure synthetic.  You won’t be able to learn the Group # of an oil you pick up at the store unless you google it.  Or if you check here, since I know a few and I’ll mention the alternatives* I’ve found to AMSOIL.

Synthetic Oils for Bikes

–Mobil 1 [Delvac or regular]

–Shell Rotella

*I only bothered looking up alternatives to AMSOIL as I needed oil right away and could not wait a week for shipping.  That’ll learn me for not stockpiling it!

Notice what is NOT on the list: Valvoline.

What if you want to use regular dino oil (Group III)?

Dino Oils for Bikes

–Mobil 1 [Delvac or regular]

–Shell Rotella / Helix


Still not on the list: Valvoline.

Don’t ask me why, but vavoline oil breaks down far before its rating should suggest.  It’s shit.  If you take nothing else from this article, take this: valvoline sucks.

The Wrap-Up

Get a multi-oil with weights that sit where you want to sit on the trade-off spectrum.  If it’s summer, go 20W50 and change it after 3k miles.  If it’s winter, maybe 5W50 and change it after 2k miles.

Don’t use SAE 40 (xxW40) in your engine.

Don’t use paint bucket liners to hold spent oil, that shit will melt ’em and bleed all over the floor. http://www.youtube.com/watch?v=d-oxmolHtEc


One Response

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  1. “Be gentle getting it out and use lube to get it in.”

    Sage advice for so many situations.


    March 4, 2011 at 3:29 pm

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