2 Stroke Oil Makes A Big Difference

[Lomax]

I run Castor 927 seems to be pretty damn good.

I agree, Thats what i run through the 250R and I like it.

[hrc85250r]

i always always use klotz supertechniplate and it works awesome, and i mix it a bit richer than 32:1....it smokes a little bit but not too much and i have never siezed anything...i figure if im paying 8-9$ a quart it better not sieze or klotz will be paying for a rebuild...

[Troll 2]

I see two ways of thinking on pre-mix ratios. Just hard to pick which.....lol



I go by this theory;
Original post;
I found it here;
http://www.motocross.com/forum/topic.asp?TOPIC_ID=21626
/////////////////////////////////////////////


Pre-mix 101

OK, looks like it's time for a little pre-mix 101. I don't usually get into ratio discussions, because mix ratios are like religions to most people, and they tend to be closed-minded on the subject, but I'll put in my $.02 here anyway.

There is a prevailing myth that less oil is better, and that the oil in the fuel is what lubricates the engine. Both are wrong. The engine is lubricated by the residual oil that builds up in the crankcase. All the oil in the fuel does is replenish this oil.

The best way to determine if you are running enough oil is to check the level of the residual oil in the crankcase. If the ratio you run leaves enough residual oil in the crankcase to cover about 1/8" of the bottom of the crank wheels, then you are fine. If you don't have that much residual oil in your crankcase when you pull the top-end off, you aren't running enough oil for your riding style and conditions.
With that said, to have that amount of residual oil in the crankcase at 50:1 (a ratio made popular by magazines and oil bottles), you can't be riding very hard, or your bike is jetted richer than necessary simply to deliver enough oil. I arrived at 26:1 for my bike with my riding style because that is the amount that gives me the proper amount of residual build-up. Small-bore engines require greater oil concentrations than larger engines to achieve the proper amount of residual build-up, because they rev higher and have higher intake velocities. Along the same lines, someone that pushes the engine harder, and keeps the revs higher, also needs to use higher oil concentrations to achieve the proper residual build-up.

To understand why the residual oil is so important, you have to understand what happens to the oil in your fuel when it goes into the engine. While the oil is still suspended in the liquid gasoline, it can not lubricate anything. It has about as much lubricity at that point as straight gasoline. When the gasoline enters the engine, it evaporates, dropping the oil out of suspension. Now that the oil is free, it can lubricate the engine, but it must get to the parts to lubricate them. The way it gets to the bearings and onto the cylinder is by being thrown around by the spinning crankshaft. Some of the oil eventually makes it into the combustion chamber, where it is either burned, or passes out the exhaust. If the combustion chamber temps are too low, such as in an engine that is jetted too rich, the oil doesn't burn completely. Instead, some of it hardens into deposits in the combustion chamber, on the piston, and on the power valve assembly. The rest becomes the dreaded "spooge". The key to all of this working in harmony is to jet the bike lean enough to achieve a high enough combustion chamber temperature to burn the oil, but also still be able to supply enough oil to protect the engine. If you use enough oil, you can jet the bike at it's optimum without starving the engine of oil, and have excellent power, with minimal deposits and spooge. At 50:1, you simply can't jet very lean without risking a seized engine due to oil starvation.

With the high oil concentrations that I use, I tend to get far more life from my cranks and rings than most of my friends that run leaner oil ratios. The high oil content also produces better ring sealing, so more of the combustion pressure is retained.

One small point. No one ever broke an engine by using too much oil.

__________________________________________________ ____________________________________

Pre-mix Ratios and Horsepower Production

I have run Dyno tests on this subject. We used a Dynojet dynamometer, and used a fresh, broken in top-end for each test. We used specially calibrated jets to ensure the fuel flow was identical with each different ratio, and warmed the engine at 3000 rpm for 3 minutes before each run. Our tests were performed in the rpm range of 2500 to 9000 rpm, with the power peak of our test bike (an '86 YZ 250) occuring at 8750 rpm. We tested at 76 degrees F, at 65% relative humidity. We started at 10:1, and went to 100:1. Our results showed that a two-stroke engine makes its best power at 18:1. Any more oil than that, and the engine ran poorly, because we didn't have any jets rich enough to compensate for that much oil in the fuel. The power loss from 18:1 to 32:1 was approximately 2 percent. The loss from 18:1 to 50:1 was nearly 9 percent. On a modern 250, that can be as much as 4 horsepower. The loss from 18:1 to 100:1 was nearly 18 percent. The reason for the difference in output is simple. More oil provides a better seal between the ring and the cylinder wall.

Now, I realize that 18:1 is impractical unless you ride your engine all-out, keeping it pinned at all times. But running reasonable ratios no less than 32:1 will produce more power, and give your engine better protection, thus making it perform better for longer.




%%%%%%%%%%%%%%%%%%%%%%%%%%%

or this?


Another way of thinking found here; http://www.macdizzy.com/oil2gas.htm



If you get the opportunity to take apart an engine very often you may notice that the bottom end of a two stroke almost always has a substantial amount of oil laying in the cases. Even in engines that have been run at leaner oil to gas ratios (50:1 to 100:1) there is plenty of oil. The other internal parts of the engine also are well coated wet with oil. It doesn't matter if the motor is air cooled or liquid cooled - the internals of the engine are still coated. Much of this oil may accumulate at idle and during periods of low rpm running. Once you get the motor spinning faster and it is under load, that extra oil in the case may finally have a chance to become suspended again in the fuel and air mixture and perhaps be burned.

Many people will rev their engine to clear that oil (that plume of smoke they get at startup or after idle) and refer to it as "cleaning out" the engine. And that is exactly what is happening. That oil - which has become separated from the fuel has gathered in the cases and is standing by waiting for some serious turbulence to get it up the transfer ports and into the cylinder where it can finally be burned. Too much oil in the gas can lead to additional problems like carbon deposits on the piston crown and cylinder head, sticky rings, fouled plugs and wet drippy black gunk (unburned oil) coming out of the joints of the exhaust system.

It is probably best to avoid sustained periods of idle, or very low rpm running under no load. It is also probably better to choose a lower gear (for instance 3rd at 5000 rpm instead of 4th at 3800 rpm) and let the motor spin faster when driving at slower speeds since there in less likely a chance of the oil not finding its way to the combustion chamber. It is my opinion that if you use top quality oils (synthetics are the best) you are only throwing away money and making more smoke by running more oil through the engine than it needs. I have had good luck by always using the same oil to gas ratio and the same oil brand.


Anyway it's interesting.........

[The Goat]

bump for a good read...

[factoryX]

I agree with the bump, great info here. I run Klotz R-50 in my R and my Z before somebody totaled it... What is the best mixture? 32-1? or 40-1? I could never figure it out.

[The Goat]

from what this said the best mixture depends upon your riding style.

I'll be running 127:1 in the 350x thanks to Ronnie

[DixiePlowboy]

I settled on 32:1 20+ years ago and stuck to it....and I've never had a failure due to lack of lubrication.

[factoryX]

true... but the oil I have right now is better than what was made back then...no? ALso, how long does oil last on the shelf?

[DixiePlowboy]

true... but the oil I have right now is better than what was made back then...no?

Golden Spectro, Bel-Ray MC+1, etc.... now is the same as it was then. Your crank, rod bearings, piston need as much lubrication as they did then. Be careful not to buy into the "then-less/now-better" frame of mind.

I got 6+ years on the original topend and spark plug from my new '86 Tri-Z using "inferior"oils from the day mixed at 32:1, so I'll stick with that ratio though I'm now using maxima castor927 and Klotz R-50 depending on the season.

[ProCarbine2k1]

AWESOME READ!!! I've been cutting a LOT of wood lately, and from this read I will be changing some things for sure (only 2 strokes I have- chainsaws and bikes). Especially reading the difference in smaller 2 stroke engines vs. the larger 2 stroke engines. Again great info!

[factoryX]

okay... I agree with 32-1.

[Twilight]

32:1 for all my stuff. My Pilot, 350, Gyro, and trx250 all do great on it. I run all with amsoil. It makes for great plug chops and burn pattern reads.

[grandy]

Thanks guys, awesome read, I love threads like these, very informative for us newbies.

[Tri-ZNate]

AWESOME READ!!! I've been cutting a LOT of wood lately, and from this read I will be changing some things for sure (only 2 strokes I have- chainsaws and bikes). Especially reading the difference in smaller 2 stroke engines vs. the larger 2 stroke engines. Again great info!

We used Klotz Supertechniplate in our husky last weekend cutting wood (50:1). Ran alot better than when it was on 50:1 husky oil

[300rman]

i ran some iffy oil in my 3 wheeler, then i switched to KLOTZ and ran a tank of r-50. ran WAY better, and now i use Super Techniplate in everything. havent replaced a spark plug in ANY of my 2 stroke machines yet.

also, i ran it in my 80, and after about 150-200 HARD hours, the top end was still nearly perfect....no scuffing of the piston, and everything was tight. I will never use anything else, and to top it all off, it smells GREAT!