Valvoline pro v Karting oil

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strange. Do racers put 2 stroke oil in 4 stroke fuel for some reason? If so, then that may explain since it is a speciality oil obviously.
But I really don't know
 
I've heard of people using 2 stroke oil in the crankcase of 4 strokes quite a bit, I mean if you think about it the 2 stroke oils must be some pretty stout oils to be capable of protection at ~50:1 ratios thinned with gas so full strength in your crankcase should work just fine. I think I remember reading that this Valvoline karting oil was capable of being used in the sump of the Animal or flathead motors as well as mixed with gas for your 2 stroke engines.
 
I notice on 2-stroke dirt bikes that use pre-mixed gasoline, a line of
engine oil dripping from the exhaust pipe.
With better oil, the line becomes thicker and the blue smoke less.
Also with better 2-stroke engine oils, it seems that I could use
28:1 instead of 40:1 without an increase in blue smoke, but the line
of oil from the exhaust pipe increases.

I'm guessing that somehow the oil is separated from the gasoline
during operation. The higher the RPM, the better.
Would this indicate that high RPM 2-stroke engines can
tolerate a higher oil ratio than low RPM 2-stroke engines?
 
Originally Posted By: used_0il
And mixes with alcohol too!!
Nothing like a couple of drinks
before hitting the track to
lose the fear-factor.


And bowel control.
 
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Originally Posted By: used_0il
And mixes with alcohol too!!
Nothing like a couple of drinks
before hitting the track to
lose the fear-factor.


Now that is funny
laugh.gif
 
Originally Posted By: used_0il
I notice on 2-stroke dirt bikes that use pre-mixed gasoline, a line of
engine oil dripping from the exhaust pipe.
With better oil, the line becomes thicker and the blue smoke less.
Also with better 2-stroke engine oils, it seems that I could use
28:1 instead of 40:1 without an increase in blue smoke, but the line
of oil from the exhaust pipe increases.

I'm guessing that somehow the oil is separated from the gasoline
during operation. The higher the RPM, the better.
Would this indicate that high RPM 2-stroke engines can
tolerate a higher oil ratio than low RPM 2-stroke engines?


In the 2-stroke dirtbike world, excess unburnt oil leaking from the silencer or exhaust flange area is commonly known as 'spooge'.
You never ever cure this by changing the premix ratio, you have to re-jet the carburation for the ambiant conditions: temperature, elevation and humidity.
The choice of oil also affects this, 'racing' type oils with very high flash points used in non-racing condition never get hot enough to completely burn properly.

A 'perfect' carburation setting on a dirtbike can tolerate at most a 10°F to 15°F temperature swing before it requires re-adjustement to keep it in tune meaning
a change in one or more of the carburator's metering circuits: air screw, pilot jet, needle, needle clip position, main jet.

Mix ratios,
it's been dyno tested that more oil makes more power (at the expense of throttle response) due to better piston ring sealing.
High-revving 125cc and smaller (12500rpms) motocross engines run in the 28:1 to 32:1 range,
while lower revving 250cc and larger or, enduro / off-road type bikes can safely run in the 40:1 to 60:1 range.

On my YZ125 dirtbike, it can mean starting off the day in cooler weather and having to
re-jet the carburator by lunchtime to keep it in ideal tune, due to temperature rising.
 
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The problem I have is with elevation change.
On a single day the bikes may see 7,000 ft
between Pemberton and Lillooet BC
down to sea-level at Squamish.
Jetting is always a compromise.

Another variable is pump gas compared to
dyed marine premium that contains no alcohol.

The fuel injected snowmobiles are thankfully far more
forgiving than the carburetors on dirt bikes.

The new machines are far more fuel efficient as
a result of fuel injection.
 
Originally Posted By: johnnydc
Thanks for the input folks. I always thought that 2 stroke and 4 stroke oils were vastly different.


It is a race only oil, so it has very little or none of the detergents or other additives that would muck up a 2 stroke.
 
I see this often regarding 2T bikes. I wonder how 2T outboards react to different ratios? My Yamanha says 100:1, my Mariner 30 says 50:1.
Will they produce more power at say 30:1?
The Mariner is 26.3 cu in (430cc) and wot at like 5000 rpm.
(?)
The Mariner run "dry" and quite well with 90:1 Amsoil, good throttle response, fells snappy, as said. But maybe it will have more pull with more oil?

Originally Posted By: mlatour
Originally Posted By: used_0il
I notice on 2-stroke dirt bikes that use pre-mixed gasoline, a line of
engine oil dripping from the exhaust pipe.
With better oil, the line becomes thicker and the blue smoke less.
Also with better 2-stroke engine oils, it seems that I could use
28:1 instead of 40:1 without an increase in blue smoke, but the line
of oil from the exhaust pipe increases.

I'm guessing that somehow the oil is separated from the gasoline
during operation. The higher the RPM, the better.
Would this indicate that high RPM 2-stroke engines can
tolerate a higher oil ratio than low RPM 2-stroke engines?


In the 2-stroke dirtbike world, excess unburnt oil leaking from the silencer or exhaust flange area is commonly known as 'spooge'.
You never ever cure this by changing the premix ratio, you have to re-jet the carburation for the ambiant conditions: temperature, elevation and humidity.
The choice of oil also affects this, 'racing' type oils with very high flash points used in non-racing condition never get hot enough to completely burn properly.

A 'perfect' carburation setting on a dirtbike can tolerate at most a 10°F to 15°F temperature swing before it requires re-adjustement to keep it in tune meaning
a change in one or more of the carburator's metering circuits: air screw, pilot jet, needle, needle clip position, main jet.

Mix ratios,
it's been dyno tested that more oil makes more power (at the expense of throttle response) due to better piston ring sealing.
High-revving 125cc and smaller (12500rpms) motocross engines run in the 28:1 to 32:1 range,
while lower revving 250cc and larger or, enduro / off-road type bikes can safely run in the 40:1 to 60:1 range.

On my YZ125 dirtbike, it can mean starting off the day in cooler weather and having to
re-jet the carburator by lunchtime to keep it in ideal tune, due to temperature rising.
 
Popular opinion suggests that better 2-stroke engine oils can tolerate a higher fuel/oil ratio such as 100:1 instead of 50:1.

Perhaps the opposite is true.
 
Depends on the application, a weed-wacker, chain saw or even some outboards engines can tolerate 100:1
Good selling points: cheaper to operate, 'better' for the environment but not ideal in the interest of better engine life and performance.

In a dirtbike, even 60:1 ( low speed off-road/enduro bikes) is pushing it, as an example in a high-revving application:

A 12500rpm 125cc 2-stroke 200lbs. race ready motocross bike puts out around 37hp's,
that is equivalent to an output of about 300hp per liter.

Even at 32:1, the service manual suggests replacing the piston and ring every 15 hours of operation
simply to get optimal performance and avoid component failures due to stress.

In between teardowns, due to ring wear I loose about 1.5-2psi of engine compression per hour of use.
 
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