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On my new KDX200 I know they run pretty rich out of the box....so if i lug it around oil drips from mid section of pipe where the silencer and expansion chamber connect....is this bad for it?

Ill probably rejet it once i get in the mood and have a little cash but for the time being is this hurting the bike?

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On my new KDX200 I know they run pretty rich out of the box....so if i lug it around oil drips from mid section of pipe where the silencer and expansion chamber connect....is this bad for it?

Ill probably rejet it once i get in the mood and have a little cash but for the time being is this hurting the bike?

Raw oil "spooge" coming out your exhaust has NOTHING to do with jetting. I am betting you are mixing your oil and gas at 32:1? That is the main problem. 32:1 is sickly rich, and only recommended by Kawasaki from a relibility standpoint. Mix at 42:1, or 50:1 and do some good long WOT runs to burn out all the raw oil, and you bike will run WAY better.

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Alright...will that affect the longevity of the top end or if i lug it around will it foul?

I guess ill just run the rest of the tank and then when its empty switch to 42:1?

Am i going to have to re-jet though?

I absolutly suck with carbs and have been afraid to take one apart since ive had a bike haha. If i had a step by step thing with pictures i could do it....but none of my friends know how to either...

Im almost willing to take it to dealer to ge it re jetted... :thumbsup:

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No it won't affect the longetivity of the top end, it will just change the amount of oil that comes out of your pipe. Run your tank dry and your carb dry too. Then switch to 42:1. You won't have to rejet unless you still have oil coming out of the ipe or you decide to put some mods on. Don't take it to the dealer and get it rejetted because they'll charge you up the ass for a 10 minute thing. Post in the jetting thread if it really needs to be done, but I don't think it will.

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Raw oil "spooge" coming out your exhaust has NOTHING to do with jetting. I am betting you are mixing your oil and gas at 32:1? That is the main problem. 32:1 is sickly rich, and only recommended by Kawasaki from a relibility standpoint. Mix at 42:1, or 50:1 and do some good long WOT runs to burn out all the raw oil, and you bike will run WAY better.

How can this have nothing to do with jetting??? You run your fuel/oil mixture at whatever ratio you wish as long as you jet your bike for that ratio. Trying to mix your fuel/oil ratio to match your jetting is the wrong way to go, it should be the other way around.

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Hurricane is correct -- you 1st pick a ratio that you plan to use, then jet your bike for that ratio. 32:1 is no problem, by the way. If you jet your bike properly, there won't be any dripping of excess oil with that ratio (I use 32:1 with no problems, and it gives great protection). But you could certainly use less oil than this if you want -- I personally wouldn't go as low as 50:1, but plenty do, without problems. On a 500cc bike, these low oil ratios make more sense, since the motor is running at much lower rpms.

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Hurricane is correct -- you 1st pick a ratio that you plan to use, then jet your bike for that ratio. 32:1 is no problem, by the way. If you jet your bike properly, there won't be any dripping of excess oil with that ratio (I use 32:1 with no problems, and it gives great protection). But you could certainly use less oil than this if you want -- I personally wouldn't go as low as 50:1, but plenty do, without problems. On a 500cc bike, these low oil ratios make more sense, since the motor is running at much lower rpms.

Listen guys, i've been racing and jetting bikes foir over 22 years. Like I said once, overly rich ratios, NOT overly rich jetting will gunk up an engine no matter what your jetting is. I don't know where your getting your "jet for oil/fuel ratios" theory, but all the experts I have talked with say mix at 42:1, and simply jet for weather conditions and fuel (pump or race), ambient temps, altitude, and humidity play a FAR bigger factor in precise jetting than fuel/oil ratios. (my comments are strictly from my experiences, you guys do what works best for you).

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No it won't affect the longetivity of the top end.

Mixing less oil than 32-1 WILL effect the longevity of the crank bearings and other bottom-end components like rod bearings.

There is no magic threshold for oil mixture. Generally speaking, the higher the ratio of oil, the longer the engine components last.

Is it a huge difference? No.

I ride hard, I use 32-1 like the book says.

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I run 32-1 with Yamalube 2R premix and I have the same problem. Should I run that same oil at a different ratio?

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Just a little hint, when changing your fuel mixture consider 40:1 koz if you mix 1/2 a qt of premix to 5 gallons of fuel it gives you a perfect 40:1 mixture. Plus jetting doesnt cost much, got an extra 10 or so bucks layin round? if so pull the carb off and throw a few new jets in it. packing lunch for a couple days is worth a good running bike.

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Mixing less oil than 32-1 WILL effect the longevity of the crank bearings and other bottom-end components like rod bearings.

Not nessecarily mixing 32:1 is just thrwoing a whole bunch of oil into your engine that it doesn't nessecarily need. If your an average trail rider you don't need that much oil. If your out pulling the shit out of your bike like a racer does then you need it.

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all the experts I have talked with say mix at 42:1
Your "experts" aren't experts at anything other than giving bad advice, if they told you that you fix spooge by reducing the amount of oil in your mix.

Any of you that believe that spooge is caused by too much oil in the mix are flat out wrong. If you know how to jet, you can run any amount of oil you choose, and have absolutely zero spooge.

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 and hard-headed 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. And there is also a very common belief that spooge is caused by too much oil in the fuel mix. 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. And spooge is caused by rich jetting.

When an engine is jetted too rich, the excess fuel leeches heat from the combustion process, causing the combustion chamber temperatures to be too low to effectively burn the oil, or even completely burn all of the fuel. The result is spooge and deposits. The spooge is nothing more than unburned fuel and oil passing out the exhaust.

If you have a spooge problem, you have a jetting problem. You don't get rid of the spooge by reducing the oil, you get rid of it by fixing the jetting. Correct jetting will produce an air/fuel ratio of about 14:1, which will produce combustion temperatures in the 1200 degree range. This will provide sufficient heat to consume the premix oil.

You don't choose a mix ratio based on "spooge", you choose the ratio based on the amount of oil your engine needs to provide sufficient protection and adequate ring seal. The common misconception is that mix ratios are "one-size-fits-all", when in fact nothing could be frther from the truth.The amount of oil that is correct for one rider on his bike may not be enough oil for another rider/bike, or it may be too much oil. It all depends on engine displacement, riding style, and how hard you push the engine.

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, and being distributed through the engine by the air currents moving through the crankcase. The main bearings are lubed by some of this oil dripping down through tiny "drip passages" in the cases above the bearing pockets.

People believe that the oil just rushes right through a two-stroke along with the fuel, but that just isn't so. It can take 90 minutes or more for the oil migration through a two-stroke to result in a complete oil exchange.

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.

Now we come to the issue of ring seal. Simply put, the rings alone can not effectively seal the cylinder. They also need oil to provide a complete seal against the bore surface. And up to a point, more oil will provide a better seal.

I have run Dyno tests on this subject, as a school project in Tech School. 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.

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Your "experts" aren't experts at anything other than giving bad advice, if they told you that you fix spooge by reducing the amount of oil in your mix.

Any of you that believe that spooge is caused by too much oil in the mix are flat out wrong. If you know how to jet, you can run any amount of oil you choose, and have absolutely zero spooge.

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 and hard-headed 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. And there is also a very common belief that spooge is caused by too much oil in the fuel mix. 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. And spooge is caused by rich jetting.

When an engine is jetted too rich, the excess fuel leeches heat from the combustion process, causing the combustion chamber temperatures to be too low to effectively burn the oil, or even completely burn all of the fuel. The result is spooge and deposits. The spooge is nothing more than unburned fuel and oil passing out the exhaust.

If you have a spooge problem, you have a jetting problem. You don't get rid of the spooge by reducing the oil, you get rid of it by fixing the jetting. Correct jetting will produce an air/fuel ratio of about 14:1, which will produce combustion temperatures in the 1200 degree range. This will provide sufficient heat to consume the premix oil.

You don't choose a mix ratio based on "spooge", you choose the ratio based on the amount of oil your engine needs to provide sufficient protection and adequate ring seal. The common misconception is that mix ratios are "one-size-fits-all", when in fact nothing could be frther from the truth.The amount of oil that is correct for one rider on his bike may not be enough oil for another rider/bike, or it may be too much oil. It all depends on engine displacement, riding style, and how hard you push the engine.

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, and being distributed through the engine by the air currents moving through the crankcase. The main bearings are lubed by some of this oil dripping down through tiny "drip passages" in the cases above the bearing pockets.

People believe that the oil just rushes right through a two-stroke along with the fuel, but that just isn't so. It can take 90 minutes or more for the oil migration through a two-stroke to result in a complete oil exchange.

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.

Now we come to the issue of ring seal. Simply put, the rings alone can not effectively seal the cylinder. They also need oil to provide a complete seal against the bore surface. And up to a point, more oil will provide a better seal.

I have run Dyno tests on this subject, as a school project in Tech School. 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.

:thumbsup:

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Yeah, I think you guys just got owned.

Awesome write-up, Chokey.

Edit: Sticky this. This question gets asked over and over again.

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If any of you are still wondering who's right, it's chokey.

"You can't swing a dead cat in the pits without hitting a bike that's running 50:1 and spewing more oil than the exxon valdeze" - Rich Roerich, engine tuner

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Interesting writeup.

I will say it one last time..... i've been racing and jetting for 22 years, i've raced 6 different KX's and replaced about 40 top ends........ I have only lost one crank, and lost one other top end from a blown head gasket due to my own stupidity, NOT the oil/fuel ratio. I do things MY way, and have my own opinions. Sorry I am "old skool" You young internet educated bred Motocrossers need to realize 20 years ago, there was NO internet, so you talked to the people who knew, and knew what worked. and it works for me. Like I said, theses comments are strictly my opinions, so don't get all internet pissy over my comments by saying "he's right and your wrong". There is NO right or wrong, just different internet opinions. I'm done with this thread.

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Run 32:1. They have been racing KX's since 1972, 1973 (whenever they were in preproduction). Since they are the one that has to pay for possibly burned up top ends, yes they will say 32:1.

Jet for your ratio.

Jet for your ratio.

Jet for your ratio.

You (everyone) needs to learn how to jet, then it won't be a problem.

To get more technical, richer means more gas, not more oil.

The oil DOES provide some lubrication (search for umpteen - I forgot to put oil in the gas and it seized posts) :-)

Chokey is no jokey.

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