More oil = less wear

[Eric K]

My data points with AmsOil...

At 50:1 ratio the top ring end gap increased 0.006" over 91 hours of ride time.
Compression was 195 psi at the start of this period and 198 psi at the end of this period.

At 38:1 ratio the top ring end gap increased 0.001" over 93 hours of ride time.
Compression was 188 psi at the start of this period and 204 psi at the end of this period.
Also note, early during this time period my water pump seal went bad and all the coolant went into the transmission, so the engine also experienced an overheat cycle.

[Fred1956]

Which Amsoil do you use?

[jostby]

Interesting notes, thanks.

I'm curious, did you use the same brand piston both times?
Did you change from "A" to "B" size or stick with the same piston size also?

I wish I had the drive to keep notes like this

[gasgasman]

Did you rejet for the different oil ratios?

More oil in the mixture leans out the fuel/air ratio.
So, in reality the motor was getting less oil.

[Eric K]

Originally Posted by Fred1956

Which Amsoil do you use?

Interceptor

Originally Posted by jostby

Interesting notes, thanks.

I'm curious, did you use the same brand piston both times?
Did you change from "A" to "B" size or stick with the same piston size also?

I wish I had the drive to keep notes like this

First one was a Wiseco, second was a Vertex.

Same size piston.

Originally Posted by gasgasman

Did you rejet for the different oil ratios?

More oil in the mixture leans out the fuel/air ratio.
So, in reality the motor was getting less oil.

I did not rejet since the engine ran fine. I can feel if I am off by one size on the pilot and a couple sizes on the main jet, which it was not.

I would like to see your math.

By my math, I am running 32% more oil per gallon of premix. Correspondingly, there is 0.6% less gas per gallon of premix, which has some small effect on the fuel/air ratio. There would also be some viscosity change, which maybe you have the formula for flow though a jet.

Taking it to the big picture level, I rode the same loops and get consistently the same fuel mileage. By my simple math, I am running about 1/3 more oil through the engine for a given ride.

[kendunn]

Originally Posted by gasgasman

Did you rejet for the different oil ratios?

More oil in the mixture leans out the fuel/air ratio.
So, in reality the motor was getting less oil.

You would be getting slightly less gasoline, and that amount more in oil. This will lean out the bike just very slightly, probably less than the jetting would be able to correct (in other words if you went richer it would be more rich now than it was lean from adding more oil). I am not using Amsoil now because of the temperature problems with full synthetic, but spring I will be going back at 40:1. Right now I am using Lucas Semi at 32:1.

[jostby]

Originally Posted by gasgasman

Did you rejet for the different oil ratios?

More oil in the mixture leans out the fuel/air ratio.
So, in reality the motor was getting less oil.

The fuel is less/oil is more to make a leaner "burn" ratio but there is more oil in the mixture which means more lubrication for the bottom end and cylinder wall

[skid jackson]

Originally Posted by kendunn

I am not using Amsoil now because of the temperature problems with full synthetic, but spring I will be going back at 40:1. Right now I am using Lucas Semi at 32:1.

I generally don't ride during the winter but ...
What are these tempeture problems that full synth has??

[kendunn]

Originally Posted by skid jackson

I generally don't ride during the winter but ...
What are these tempeture problems that full synth has??

I have heard that full synthetic doesn't like to mix well when it gets below freezing. Not sure how true it is, but figure it wasn't worth chancing and the Lucas semi seems to be doing fine. Come to think of it, I wonder if snowmobiles run full synthetic? Or maybe they are injected?

[gasser]

Originally Posted by kendunn

I have heard that full synthetic doesn't like to mix well when it gets below freezing. Not sure how true it is, but figure it wasn't worth chancing and the Lucas semi seems to be doing fine. Come to think of it, I wonder if snowmobiles run full synthetic? Or maybe they are injected?

I don't know about the other synthetic oils but I've used all 4 of Amsoils 2 smoke oils and they mix and work fine at below freezing temps. I ride all winter long in Tennessee and a lot of our winter ride days start out below 30F.