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Hi everyone,
As you all know, Coffee (Dean) passed away a couple of years ago. I am Dean's ex-wife's husband and happen to have spent my career in tech. Over the years, I occasionally helped Dean with various tech issues.
When he passed, I worked with his kids to gather the necessary credentials to keep this site running. Since then (and for however long they worked with Coffee), Woodschick and Dirtdame have been maintaining the site and covering the costs. Without their hard work and financial support, CafeHusky would have been lost.
Over the past couple of weeks, I’ve been working to migrate the site to a free cloud compute instance so that Woodschick and Dirtdame no longer have to fund it. At the same time, I’ve updated the site to a current version of XenForo (the discussion software it runs on). The previous version was outdated and no longer supported.
Unfortunately, the new software version doesn’t support importing the old site’s styles, so for now, you’ll see the XenForo default style. This may change over time.
Coffee didn’t document the work he did on the site, so I’ve been digging through the old setup to understand how everything was running. There may still be things I’ve missed. One known issue is that email functionality is not yet working on the new site, but I hope to resolve this over time.
Thanks for your patience and support!
fuel oil mixture 32:1 or 40:1 wr 250 83 ???
- Thread starter megagobby
- Start date
This subject always gets mixed responses. A lot of people swear by modern oils even in an older engine and say running at 50:1 is fine, then there are others who say you should use an oil which is similar to the old oils from back in the day and run at the typical 20:1 used back then. I personally use Putoline MX5 at 32:1 in my YZ125 and will also use this in the 390 Husky I am rebuilding. I had a 1984 CR250 Husky and it was also fine on this oil at 32:1. I think this is a good middle ground between the 20:1 some people prefer and the 50:1 others say is fine with modern oils.
The thing to remember is that the oil/fuel ratio will have an effect on the jetting, so if you decide to use a ratio of 50:1 the bike will run richer with the standard original jetting sizes recommended for 20:1. I am sure you know this, but if there is less oil in the fuel, there is more gas, so you will find you will have to go to a leaner jetting set up than if you run at 20:1.
Are you changing from a different oil at a different ratio, or is this the first time running the engine after a rebuild?
The thing to remember is that the oil/fuel ratio will have an effect on the jetting, so if you decide to use a ratio of 50:1 the bike will run richer with the standard original jetting sizes recommended for 20:1. I am sure you know this, but if there is less oil in the fuel, there is more gas, so you will find you will have to go to a leaner jetting set up than if you run at 20:1.
Are you changing from a different oil at a different ratio, or is this the first time running the engine after a rebuild?
tommie d
Husqvarna
AA Class
I went back to what the factory recommended. Bel-Ray at 25:1 I don't care what people say about "modern oils" or "oils have came along way since the bikes were made" WHY? because we had synthetic oils in the 70's like Bel_ray and Amsoil just to name a few. Just make sure you jet your bike correctly. Here is something you might want to read. http://articles.superhunky.com/4/194
I love oil threads.
I love oil threads.
Dirtdame;121446 said:Good modern full synthetics can be run in old or new bikes at 50:1 ratios or higher. I use Motorex at 60:1 in all my two strokes except for my Gas Gas trials bike which I use Motorex at 100:1.
Couldn't have said it any better.
It's like you took the words right out of my mouth.Hey DD I didn't know you have a Trials. Do tell.
endurokids
Husqvarna
AA Class
I've been racing my '83 XC 250 for 3 years now and have not replaced anything other than the clutch. I race H/S 1-2hrs minimum per event and even run the modern classes with it.
I've run Golden Spectro Oil in my bikes at 50:1 since 1983, and will continue to do so as long as the product remains as good as it's been to us.
I've run Golden Spectro Oil in my bikes at 50:1 since 1983, and will continue to do so as long as the product remains as good as it's been to us.
One of the Club locals was cleaning out his garage and had a very thrashed, sad 2001 TXT280 looking for a cheap date.HuskyDude;121502 said:Couldn't have said it any better.
Hey DD I didn't know you have a Trials. Do tell.
Old Geezer
Husqvarna
A Class
Well boys and girls, I've been 32:1 since way before I was 32. Call me old, call me old-school, call me paranoid about longevity when running thinner ratios. I'm probably misinformed in that regard. Heck, in the very early days right around when Kennedy was assinated, we ran 28:1 and felt really daring when we graduated to 32:1.
Old habits die hard. What works for you....works for you. Just make sure to get your carb jetting correct, especially when/if you start messing with the F\O ratio.
Old habits die hard. What works for you....works for you. Just make sure to get your carb jetting correct, especially when/if you start messing with the F\O ratio.
This is a very good article & may be of interest
http://articles.superhunky.com/4/194
BTW I will be using 32:1 in my '71 400..and I'm using Golden Spectro
http://articles.superhunky.com/4/194
BTW I will be using 32:1 in my '71 400..and I'm using Golden Spectro
tommie d
Husqvarna
AA Class
Hammer posted this over in the 2-Stroke section today. I thought I would repost it here just incase you missed it. I realy liked this as it follows along with my old school thinking.
--------------------------------------------------------------------------------
Here is something to think about
Spooge...
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.
--------------------------------------------------------------------------------
Here is something to think about
Spooge...
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.
