Uh....I don't think anyone is advocating running two stroke oil in their four stroke for extended/normal everday operation. A tankfull of premix for prepping the engine for storage was the recomendation and is an excellent way to "fog" the motor with oil. It coats the intake valve, piston, walls, exhaust port and exhaust valve stem and even the inside of the pipes a little if you run it long enough.
I have been prepping 4 stroke engines with two-stroke premix oil in them for over 30 years and it has always worked excellently. I have had none of the problems mentioned as a possible negative of the two stroke oil.
I have put 4 stroke motors away for as long as 5 years at one point and they were perfect inside from being prepped with two-stroke oil. I have NEVER had a carburetor problem with two stroke premix prepped engines. Never. Plus, I have never had any problem with the fuel "souring" or generating excess peroxides (that is what you smell when the fuel breaks down and sours and smells like crap) when it has two stroke oil in it.
Granted the oil in the gas will not necessarily "stabilize" the gas....but guess what....neither does Stabil no matter what their marketiers say. If you run an engine with Stabile and tear down the carb or fuel system months later you will find the oily residue of the Stabile. Just like you will find the oily residue from the two stroke oil if you had used that. The whole purpose is to prevent deposits from clogging things up...not "stabilize" the fuel. It will evaporate regardless of Stabile or pre-mix so you have to protect against the deposits.
The whole point is to provide a residual oil film on parts where the gas evaporates so as to prevent any varnish or deposits from the gas evaporating from sticking or clogging orifices. The residual oil does exactly that from the pre-mix. The residual oil film also provides protection against corrosion on any steel or aluminum parts, injector orifices, valve stems, etc....
Since many two strokes inject the oil into the crankcase directly instead of into the gasoline going into the carb it is even necessary to mix up some premix for most two strokes and put it into the tank to adequately prep them and protect the carbs. Part of the myth why people think the two stroke oil won't work as advertised. They don't realize that the carbs are running straight gasoline and not protected by the oil unless you run premix thru the tank.
The little bit of oil from the premix will not hurt the cat. Oil poisons the catalytic converter (theoretically) because of the phosphorus in the anti-wear additive package. It doesn't "clog" it or necessarily cause it to run too hot or anything. It just slowly poisons it. Slowly....like....if your engine used a quart of oil every 1000 miles you might start to notice the catalyst efficiency would start to drop after 100,000 miles. It is NOT an overnight or low mileage type of failure. Trust me, I have seen LOTS of cats run with varying levels of purposeful oil consumption and it takes a fair amount of constant oil consumption to hurt a cat. Besides, all that happens is that it starts to emit a tiny bit more. It doesn't restrict the flow or anything. If a cat melts it was from something other than oil consumption. I saw one test recently where over a gallon of oil was added to each tankful of fuel for a thousand miles. The car would smoke on startup and oil residue was actually dripping from the tailpipe. It took almost another thousand miles for the smoke and residue to clean up. Afterwards, the cat was fine and the vehicle passed emissions fine. The heavy dose of normal SM grade, non-synthetic did no harm at all.
Synthetic oil would have killed the cat and plugged it up entirely, however. Just kidding.
As far as two stroke oil "gumming up the rings...." Hmmm..... Wonder why I have never seen this one any of my (many) engines prepped with pre-mix. Wonder why it doesn't "gum" up the rings on a two stroke if it is so bad?? Fact is it doesn't and it won't. Two stroke oil is blended to be burned and thus has specific detergents in it to prevent ring belt deposits even if you ran a steady diet of it.
It is a fact that adding two-stroke oil to the gas will displace some gas and make the engine run a bit lean. We are talking about prepping the bike for storage, right, not adding premix for a track day or a run at Bonneville or something. For the purposes of prepping the bike having the mixture 4% lean with a 25:1 premix ratio will not hurt anything at all. Besides, if your O2 is hooked up and working then it will compensate while you motor along on your prep and there is no worry. 4% lean is nothing to worry about anyway unless you are running the engine at WOT continuously....and then premix is not recommended anyway.
The description of the two stroke is pretty close right up to the part where it mentions "the mixture is pushed to the top of the piston through the transfer ports where it fires. By this time it has very little oil left in it. What little oil that is still in the mix is still not a good thing even in a two-stroke motor." If the mixture has very little oil left in it by the time it gets to the chamber WHAT HAPPENS TO ALL THAT OIL? Think it just builds up in the crankcase and stays there? Of course some of the oil falls out of suspension in the crankcase due to mixture motion and centrifugal force. But the mixture picks up an even amount of oil and carries it right to the chamber where it is burned and goes out the tailpipe. The chamber is always seeing the same pre-mix ratio as the gas has in it or that the oil injection is delivering. Otherwise you would have to stop and drain the oil from the crankcase occasionally.
I just took my snowmobile engine apart with over 9000 miles on it. It is a two stroke and I run a fairly "rich" oil mix on the injection setup. It averages about 35:1 over the long haul. (oil is cheap....pistons and crank bearings are a PITA to replace) The pistons looked fine. Clean, rings perfectly clean and NOT "gummed up" or stuck or anything. Very little carbon on piston or in the chamber of the head. Totally clean exhaust port valve (mine has the RAVE system). Totaly red herring to say that two stroke pre-mix will cause a problem with deposits even in a four stroke.
BTW....warsw needs to read up on the latest in two-stroke technology. They are not the dirty pollutors described. The latest of the two strokes run fuel injection injectors in the transfer ports so no fuel is put into the crankcase and the fuel is only added to the intake charge AFTER the exhaust port has closed. No HC being pushed out the exhaust due to overlapping flow from the inlet. Plus, since the crankcase mixture is not diluted by gasoline the amount of oil needed is miniscule. The oil is injected directly into the crankcase and crankcase bearings for maximum effect. Part of the crankcase main bearings are packed with grease and sealed so they are not even lubed by the pre-mix anyway. Very little to no smoke and excellent emissions and fuel economy. What is not to like? You'll see them around for a while yet in the powersports industry as they are hard to replace for power, low mass and simplicity. Especially now that they meet the 08 and 09 emissions standards for such engines.
