Gas Mileage?

[redbirds_imp]

I contemplated starting a new thread, but since this thread already has some good information, I figured I'd just add to it.

I was consistently getting between 40 and 42 mpg on my 2014 Std 6 speed.

I weigh about 230 lbs and do mostly suburban driving, ie., average speeds between 35-45 mph but a fair amount of stop signs and lights.

This Spring I changed the oil out from Honda "dino" 10w40 and went with Rotella T6 15w40 full synthetic. My gas mileage immediately improved to 46-48 mpg... And it's been consistent.

Until last week... Yesterday I measured 52 mpg!

That's both by pen and paper and the built-in mileage calculator.

I have another bike that was acting like it had dirty fuel injectors, so I got some Techron injector cleaner for the other bike and it cleared things up.

I had half a bottle of Techron left over, so I dumped it in the CB1100 with a fresh tank of gas.

I had absolutely no apparent issues with the fuel injectors on the CB1100, but it seems like the Techron did some good. 52 mpg is an all-time high for me, and we'll see if it remains consistent.

FWIW, The 15w40 makes the valves a bit louder compared to the 10w40, but I did experience about a 10% mileage improvement immediately following the change to Rotella 15w40.

I know, correlation does not equal causation, and the slightly noisier valves are making me consider a Rotella T5 10w30 for next year, but I'm fine with the T6 15w40 for now.

I have used Shell Rotella T6 synthetic 5W-40 in all my bikes for years now, including an ST1300, Bonneville, Tiger 1050, 2 V-stroms, 2 CB1100s and now 2 NC 750's. The greatest difference noted was in a CB1100 that constantly balked on 3rg gear engagement; I had been using the Honda synthetic 10W-30 during the warranty period and thought that getting it broken in would clear it up. After switching to the Rotella the 3rd gear problem cleared up immediately.

I see a lot of people here have used the T6 5w40, but after a visit to the "Bob is the Oil Guy" forum, I decided to go with the 15w40 due to its resistance to shearing.

From my understanding, the downside to using oil that's too thin is premature cam wear, which won't show itself until it's too late.

I'm absolutely convinced that the 15w40 is the correct weight and viscosity for my VT750 Shadows, but it does add some valve noise to my CB1100.

I'm considering the Rotella T5 10w30 for my next oil change interval, but since the T6 15w40 seems to be giving me good results otherwise, I plan to leave it in for 4k miles.

Rotella was designed to prevent "shear" in diesel motors and is not dependent on oil weight. Motorcycle oils are similarly formulated since most share oil to the gears. I like Rotella 5W-40 because it allows maximum lubrication at startup but has all the properties of a 40W when warm thus it delivers the best of both worlds.