A question for members of the mechanical brains trust...

[Sparti]

Ever since getting speedy, I've run 15w-50 oil, and more to the point Mobil 1. Then I changed over to Motul 15w-50 and found it to be very good, especially with smoother gear change. So then for this oil change I continue with Motul but this time go with a 10w-40.

Here's the question. Would a 10w-40 oil make the bike run noisier and even cause more engine vibration to be felt.

These are two things I've noticed since my last service and I'm pointing the finger at the oil. What do you think?

[Brrapp]

yes

The oil is thinner and offers less cushioning.

Normal practice would be thicker oil in summer, not thinner you big silly!

[Martin_R]

You can definitely hear more clatter from the top end with the thinner oil. But to get major vibrations sounds a bit worrysome. There must be some out-of-spec tolerances somewhere, if you need thick oil to take up the slack. People usually use unnecessarily thick oil in their run-to-the-ground sloppy loose cars, just before trading them in.

Easy & cheap enough to try, if going back to 15-50 changes anything? You could doublecheck the old oil at the same time for metal shavings.

What were all the things you did to the bike on the service where vibrations appeared?

[Chewie.]

What were all the things you did to the bike on the service where vibrations appeared?

[2doggs]

I could have answered that.

[rnexussix]

+ 1 on more noise from engine on 10-40 then 15-50. But here is a funny twist;
With 15-50, the bike would burn about 1/2 qt within 3000 miles. With 10-40 less then 1/8 of a qt. (both weights same Mobil 1)

[Sparti]

The vibration can be felt through the pegs and at the waist of the bike where you hug the bike with your legs. It's not a violent vibration, just a slight increased tingling. It's just that my bike hasn't felt like that before so I noticed it.

I definitely think its the thinner oil.

[Sparti]

[Sparti]

+ 1 on more noise from engine on 10-40 then 15-50. But here is a funny twist;
With 15-50, the bike would burn about 1/2 qt within 3000 miles. With 10-40 less then 1/8 of a qt. (both weights same Mobil 1)

My bike burns no oil at all, never has.

[antisocial]

you sure you didn't get your chain too tight? I run nothing but 10W40 in mine, and it's smooth. 10W40 seems quieter to me