Actual Fuel:Oil Ratios

[rotax]

Just wanted to give an update on oil usage since I had my engine rebuilt, and oil pump turned up [quite a bit].

I can't say exactly what I was getting before, but I was using very little oil each ride.

The one "before" number I have is at 45:1 before [adjusting pump].

I'm now pretty consistantly ~37-38:1 after [turning up the pump] (last 6 rides were 37, 38, 37, 38, 38)

The more WOT the more oil usage.
I had one ride in summer/spring like (setup) snow conditions, 90% road/trail riding, doing a belt break-in; where I had 55:1 and 9.67 MPG. I didn't go beyond 1/2 or 2/3 throttle more than a few times that day..

Anyway, was just curious what others are seeing for properly/accurately calculated fuel-oil ratio.

Calculation I'm using:
[gallons of fuel] *128 = ounces of fuel
[ounces of fuel] / [ounces of oil] = ratio

ex: 5 gallons * 128 = 640 oz of fuel
640 / 20 oz of oil = 32:1 ratio

 

[barkbuster]

I put 900 miles on my 12 Pro 163 this year and measured every drop of oil and fuel that went in. Ratios ranged from 45:1 to 48:1 for off trail riding. I had one trail only ride at 55:1. My pump setting is stock, and right on the marks.

 

[Reg2view]

Pump turned up 4 turns, no threads left, stock was just above the line, now way above the line. I don't believe it could be turned up more.

After adjustment:

Lotz of trail, 43:1.

Pinned in the deep, 36:1.

Was very precise in the most recent measures, both fuel, and oil, filling oil from a pre-mix oz cup.

Stock, it had to be 55:1 or more, even pinned. I never measured precisely, but would say it uses 1.5-2x the oil it did stock. Zero fouling issues. Using E3's.

 

[joshkoltes]

i had readings of 52-56 stock turned it up to 42 ish

 

[rotax]

Great feedback. Looks about par for what I've seen stock vs turned up.
Hopefully its the key to longevity in these engines...

 

[mike_s]

I think it will be one of the keys, but not the only one. There is an inherant design flaw in these engines, we commonly call short rod syndrome. There are bandaids you can do to help it (fix it kit), but will never be quite right.

 

[IQRIDR]

I think it will be one of the keys, but not the only one. There is an inherant design flaw in these engines, we commonly call short rod syndrome. There are bandaids you can do to help it (fix it kit), but will never be quite right.

Rod to stroke ratio plays a large factor in rod bearing life, piston life. The compact design of the 800CFI leads to a motor that is nowhere close to "square" and that leads to a myriad of other problems..

 

[knifedge]

800cfi is same bore stroke as cat 800. Cat 800 wrist pins are offset so no issues with skirts. Cat 800 uses oil so crankshaft is happy also. I believe RKT kit does this for CFI 800 drop in kit.

 

[knikflyer]

I am driving a 2011 144" SBA with factory oil pump setting. Ratio came out to 52:1 with a fair amount WOT doing some hill climbs and running wide open across some rolling hills. Conditions were 12"-18" of fresh on top of good base. Got 7.5 miles per gallon doing it. Basically 80 miles is all I can go and make it back to the truck with 1 gallon left in tank under those conditions

 

[NWBackcountry]

My oil pump is set up just below the center of the mark. When running mostly half throttle, becasue of crappy snow, the ratio is around 50:1. When running wide open all day in good deep snow, the ratio is 32:1. I also put an ounce of oil per gallon in the fuel tank. I might stop putting the oil in the tank since my ratio from the pump seems pretty good. I am running a 14:1 head and 96 octane non-ethanol.1550 miles.