Engine oil.

[F6Ghostrider VRCC #32501]

At 175,000 miles, I switched to a full synthetic blend of oil. I have always used 10W-40. This time, I inadvertently ordered 5W-40. My question is, "Can I safely use the 5W-40 for this oil change and switch back to the 10W-40 at the next service?"
Thanks,
Jeff.

[Grandpot]

It shouldn't be a major issue.  You may burn a little when you start up cold, but it should run fine.  Just keep and eye on the level.

[Jess from VA]

With no scientific proof, but being on this board for many years, it's very possible the single most used oil in Valkyries is Shell Rotella T6 full synthetic 5-40.  I probably ran 15 gallon jugs of it my 2 bikes for many years with no issues.  And I never burned (or lost any) either.   

The imperative is that your synthetic oil not contain friction modifiers.  (with the wet clutch)

[h13man]

As mentioned, is the oil MC compatible would be my only worry. T6 Rotella 5w-40 is the only oil I used with with that 5w-40 specification safe to use in MC's.

[Chrisj CMA]

At 175,000 miles, I switched to a full synthetic blend of oil. I have always used 10W-40. This time, I inadvertently ordered 5W-40. My question is, "Can I safely use the 5W-40 for this oil change and switch back to the 10W-40 at the next service?"
Thanks,
Jeff.

Does it say energy conserving at the bottom of the info circle or is it blank? Blank is what you need!

[rug_burn]

Well, it's going into winter, so that's a good time for thinner oil...
It's been Mobil 1  15/50 for me, no complaints for 184 K  miles

[Gideon]

At 175,000 miles, I switched to a full synthetic blend of oil. I have always used 10W-40. This time, I inadvertently ordered 5W-40. My question is, "Can I safely use the 5W-40 for this oil change and switch back to the 10W-40 at the next service?"
Thanks,
Jeff.

Jeff, Many on this forum use Rotella T6, 5-40 Synthetic Oil and a Purolator Pure One PL14610 Oil Filter.

[Bighead]

I personally like 3 in 1 machine oil

[Jess from VA]

I personally like 3 in 1 machine oil

I do too, but Vaseline is a bit more hygienic.   

[Madmike]

This article gives a basic description of how VI improvers function in lube ols.

https://www.machinerylubrication.com/Read/1327/viscosity-index-improvers

5/40 is a bigger spread than 10/40 so there is marginally more possibility of shear is my thought but I wouldn't be concerned personally.  It is winter so you may get a bit better cranking with 5w oil as you may have cooler temps.

Big thing is the friction modifiers that they add for the "energy saving" oils that can help create trans slippage problems.

[jnicks01]

Layman's terms...

5w or 10w is pretty much irrelevant as that is the cold starting weight.  If you live in a cold climate you would want lower for better turn over when starting.  The viscosity (second number) is what you want to focus on.  "40" is recommended and will be fine.  I myself, run 15W-50 Mobil 1 full synthetic and it protects just fine.  At least I think so seeing I have no metal in my oil changes.  As others have mentioned, just NO friction modifiers, etc. 

Others may provide some more scientific information but that's my experience. 

[F6Dave]

Several years ago Sport Rider magazine had an extensive 2 part article about oil.  It included an analysis of 19 brands, mostly MC specific but a few automotive like Mobil 1.  A big surprise was that about a third of the oils included that dreaded friction modifier, MOLY!  They even found some in Honda's HP-4.

The article is still available on the Cycle World website.

[98valk]

Several years ago Sport Rider magazine had an extensive 2 part article about oil.  It included an analysis of 19 brands, mostly MC specific but a few automotive like Mobil 1.  A big surprise was that about a third of the oils included that dreaded friction modifier, MOLY!  They even found some in Honda's HP-4.

The article is still available on the Cycle World website.

moly is not a problem until it gets into the 200-500ppm range and at elevated temps. the original slippage report was the starter clutch and NOT the engine clutch.   I have the SAE report.  Mobil has moly in their m/c oil, as do other m/c oils.

[F6Ghostrider VRCC #32501]

Thank you for your personal experience and opinions. Puts my mind at ease. I'm just going to run what was sent to me and switch back on my next oil change. The vendor refunded my money on the 5W (much appreciated and certainly not expected) so I'll take his refund  and purchase the 10W from him.
Thanks again
Ride safe and keep the rubber side down.
Jeff.

[Led]

Spec's on the engine say 5w/30.........

I have been using the 5w/40 Mobil 1 Diesel oil.  Even comes in the PERFECT 4 quart jugs!

No problems with that at all.........

Since the Valk oil also services the tranny......a "little" more heavy duty cannot hurt??

https://www.walmart.com/ip/Mobil-1-Turbo-Diesel-Truck-Full-Synthetic-Motor-Oil-5W-40-1-Gal/17128879

[98valk]

hope they mean 10w30 based on 1988 oil specs up to 90F.

never ever was 5w30 spec'd for the GL1500 engine.

[Chrisj CMA]

I'm on my last gallon of 20/50 vtwin motorcycle specific Mobile 1. I like it a lot I may go to the bike shop and pay more for it than car oil at Walmart.

I'm at 1,000 miles after oil change and it's exactly at the same level it was at day 1. Barely touching the tip of the stick when screwed in on the side stand

All good.

[mello dude]

I'm on my last gallon of 20/50 vtwin motorcycle specific Mobile 1. I like it a lot I may go to the bike shop and pay more for it than car oil at Walmart.

I'm at 1,000 miles after oil change and it's exactly at the same level it was at day 1. Barely touching the tip of the stick when screwed in on the side stand

All good.

Walmart sells that too... I like the 4T 10w-40 Mobile 1 motorcycle oil and typically Walmart has the best prices for that....

[Chrisj CMA]

I'm on my last gallon of 20/50 vtwin motorcycle specific Mobile 1. I like it a lot I may go to the bike shop and pay more for it than car oil at Walmart.

I'm at 1,000 miles after oil change and it's exactly at the same level it was at day 1. Barely touching the tip of the stick when screwed in on the side stand

All good.

Walmart sells that too... I like the 4T 10w-40 Mobile 1 motorcycle oil and typically Walmart has the best prices for that....

Cool. Thanks. I'll look