I'll look up the stock jetting and get back with you.
If you are happy with the way the bike is running then don't change anything.
I do agree with #42 if you have a chance you might re-pack the silencer as I'm pretty sure it's soaked.
The next thing that usually follows is the packing falling apart and into and or through the pipe.
We could work through this if you like, just remember it will take time to clear out the whole system.
I wish I was smart enough to have written this all by my lonesome.."Chokey" or "Spanky" is the original author. I have attempted to take some of the "sting" out of the paper. As it is not my intent to offend anyone, least of all a poor chap actually trying to find answers, and do what's right.
Chokey's post on the subject here: 3rd post down
http://twostrokemotocross.com/forum/index.php/topic,59.msg2468.html#msg2468 Spankys jetting guide:
http://www.kawasakimotorcycle.org/forum/kawasaki-motocross-offroad/17227-spankeys-jetting-guide-info-2-stroke-riders-must-have.htmlAnyone that believes that spooge and plug fouling are caused by too much oil in their Pre-mix May have been misled.
If you know how to jet, you can run any amount of oil you choose, and have absolutely zero spooge.
You may not be old enough to remember, however I never saw any drooling on any factory mx bike, or for that matter any factory race bikes.
There is a prevailing myth that less oil is better. This simply isn't the case.
While true,there isn't a magic "one-size-fits-all" mix ratio, and it is possible to use too much oil for your conditions, generally speaking, more oil is better, within certain limitations.
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.
It may leak from the exhaust flange at the head pipe/expansion chamber,the joint at the silencer to expansion chamber and right out the silencer tip onto your fender. The exhaust valve may be fully engulfed as well as the silencer packing.
A spooge problem, is 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 6000F range and exhaust temperatures in the 1200F range. This will provide sufficient heat to consume the premix oil.
And,by the way is where expansion chamber producers build their pipes to operate at.
The same goes for plug fouling. Rich jetting does two things. First, it promotes incomplete combustion of the fuel and the oil due to reduced combustion temperatures. The incomplete combustion of the fuel and oil promotes deposit formation inside the engine. Second, rich jetting reduces the combustion temperatures, which in turn reduces the engines ability to burn off deposits. Combine increased deposit formation with reduced ability to burn off those deposits, and what do you get?
Spooge,plug fouling and a carbon seized exhaust valve.
Choosing a mix 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 farther 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.
A trail rider on a 500 that never reams the bike out (Me!)is probably fine on a mix of 50:1, where a super-fast up-and-coming future pro that screams an 85 'till the dogs howl the entire time he's on the track might not get a full day of racing out of an engine on less than 30:1.
Your engine's oil needs are determined by displacement, rev range, and the loads you put on it.
When you shut your engine down and let it sit, much of the oil drains down into the crankcase and forms a puddle in the bottom. The depth of this puddle is your indicator of whether you are running the correct amount of oil for your engine's needs. Ideally, you want this puddle to be between 1/8 and 1/4 inch. If it's less, you need more oil in your mix. If it's more, you are running more oil than you need for your 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 40: for my bike with my riding style because that is the amount that gives me the proper amount of residual build-up, good ring seal,and a small peace of mind factor and all with out the spooge.
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 mix ratio 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 to precipitate on to or into something, just like water on the outside of a cold glass in warm weather.
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.
The oil mist is distributed throughout the engine by the spinning crankshaft and the moving air currents to coat all the internal surfaces.
The oil moves through a two-stroke along with the fuel, true; but at a much slower rate than people think.
It can take 90 minutes or more for the oil migration through a two-stroke to result in a complete oil exchange on a slow trail ride, and even as much as 5 minutes for a full-throttle 20 minute moto.
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 in a small-bore engine, you simply can't jet very lean without risking a seized engine due to oil starvation.
The bottom line?
Choose a mix ratio that is adequate for your needs, and jet accordingly.
You don't remedy plug fouling and spooge by adjusting your mix ratio alone,
however it does play a part in tuning your engine, to your riding style & conditions.
These are an interesting read that also supports "more oil is better" claim.
http://www.bridgestonemotorcycle.com...oilpremix6.pdf
And this is a good article as well:
http://www.maximausa.com/technical/l...summer2001.pdf
