Hi,
I'm new here on the forum.
I read a lot of interesting topics on this board, like the one I wanted to know about 'Peroxide in the gasoline', being written well before I ever thought of it, and thus know that some of you probably have more experience with my next question, than myself.
For a while now, I've been testing 2 stroke oil in my 4 stroke Honda Rebel.
This topic mainly will be about using 2 stroke oil in a 4 stroke engine, but aside from my Honda Rebel, I've only used it in my 1 cylinder, 150cc lawnmower engine.
So my experiences are towards these.
Rather than talking about the Honda Rebel, I'd like to talk more about experiences with 2 stroke oil in a 4 stroke engine. Perhaps some links to some good articles, some people's experiences with it, etc...
The first thing I read about 2 stroke oil in gasoline was, that it kept the gasoline stable for longer. Necessary, because my lawnmower can be sitting in the shack for 1 month or more.
When I added just a tiny bit of 2 stroke oil, I noted the increase in RPM in my lawnmower.
I became curious, and tested it out on my Honda Rebel.
I used deductive reasoning when dosing the oil.
A 4 stroke engine needs less oil than a 2 stroke, because it needs to lubricate less parts.
How much, is the question....
I started out with dosing 100:1, did some tests, and expanded my research from 75:1 to 300:1 doses, tested, and written down the results.
At 100:1 the bike runs butter-smooth. Vibrations are way less, and a small mid-range power boost (it accelerates much better to 9k RPM, as where without the oil, the vibrations would shake the machine too much to go much beyond 7k RPM, and I would shift before getting there.
I did some research as to why, and it appears on a 4 stroke, that the top end of the cylinder is the least lubricated, and the cause of an engine's greatest friction loss.
Every downward motion, engine oil is sprayed on the cylinder walls, and the piston glides over the layer of oil.
On the up motion (compression), a gasoline/air mixture is injected, and the cylinder glides over the layer of pure gasoline, which doesn't really work as well as lubricant.
After the "explosion stroke", the cylinder goes upward, without compression, exiting the exhaust gasses. At this point the cylinder does not receive any lubrication.
Luckily at this point, the lateral forces on the cylinder walls are very low; as less force is being put on the piston at this stroke.
So from 2 out of 4 strokes lubricated (the down strokes), and 1 semi-lubricated with regular fuel,
Adding 2 stroke oil to the fuel will make that half lubrication a full lubrication; and at an important part of the stroke as well (the compression part, where lateral forces of the piston on the cylinder walls are stronger). So 3 out of 4 strokes will be lubricated!
That's the theory behind it all...
And my results are showing me vibration reduction, and performance increase are closely connected.
The engine with too much, or too little 2 stroke oil, will either have too low performance, or too high vibrations.
High vibrations leading to lower performance as well.
So, there is a sweet spot!
On the Honda Rebel, and that's conveniently at a dose of about 128:1.
Convenient for the people using the US imperial system...
It means that for every gallon of fuel, they'd need to add 1oz of 2 stroke oil.
So the measuring works out easy!
That's a good starting point for any 4 stroke engine; but depending on engine to engine you might have better results dosing slightly higher or lower.
On a 2 stroke, generally doses of 50:1 are most optimal (sometimes 32:1); so I deducted that on a 4 stroke, a dose of higher than 50:1 is necessary, since the fuel doesn't need to lubricate anything below the pistons.
I also noted that plug fouling could happen on 2 strokes, with doses below 32:1; but at 50:1 doses, there was no real plug fouling seen, and the exhaust looked clear.
On my Honda Rebel, the following observations where true (it is a carbureted bike):
75:1 : Super smooth engine (vibration wise), lowered performance.
100:1 : Great performance, smooth engine.
125:1 : about the right balance of smooth riding, and good performance.
150:1 : Great performance at the cost of minor added vibrations.
200:1 : Almost normal performance (without additives), but still noticeable less vibrations.
300:1 : The effect of the 2 stroke oil is no longer noticeable in the fuel; both performance nor vibration wise.
The performance increased from between 100:1 to 200:1, compared to regular fuel. I don't know if it has to do with better sealing valves or pistons, or just better for my bike because of unique carb setup (and Air/fuel ratio is modified).
It may be very engine specific too.. Some may benefit, while others don't...
But here's my theory on adding 2 stroke oil to the gas:
Adding 2 stroke oil to the gas, does not only rev the engine smoother, meaning less vibrations, which results in less heat generation in the cylinder walls on the compression stroke.
Less heat results in a cooler running engine. Better sealing of the valves and cylinders, also results in a cooler exhaust resulting in a cooler running engine
Oil in gasoline means heavier gas. Heavier gas means slower burns. Slower burns means more performance at lower RPM, and cooler running bike.
All this extra low end torque can be converted to a higher gearing, to get a similar performance as before.
The lower RPM of higher gears, combined with the increase in performance due to slow burn, results in similar performance, at a lower RPM/higher gear, and conceives better MPG.
So far, it seems to me, that oil always was meant to be in gasoline, as I see how nature balances and gives a more efficient running engine applying this method.
After the readout I did some math on the fuel prices.
Adding 2 oz in my 2Gal fuelup each time, costs me about 8% more on fuel. This is using a cheap 5 quart 2 stroke oil jar, found on Amazon. If using the small bottles (of 6oz each), prices could rise by upto 16%. Instead I take with me a small, 8oz plastic container, and fill it up with 2 stroke oil from the 5 quart oil jar, and put a shot in the tank just about every time I fuel up.
This method is the cheapest, and results in 8% increase in fuel cost.
MPG results showed me a consistent increase of 5MPG with same gears (I get between 75 - 80 MPG before, and 80-85MPG after), same riding style, over multiple readouts.
The 5MPG gained equates to +8% of total MPG; So my average cost is completely offset by the increase in MPG I get per tank, and a cooler running engine, with less vibrations, which could mean a longer lasting engine.
Again, only benefits!
Financially I pay the same; but I can do more miles per tank, and I have a better, more efficient running engine.
All good in theory, but the only thing so far that's been suffering the heavier gears, faster top speed, and more power, is my clutch.
I just have to be cautious with the clutch, that it won't slip, but so far, it's a non-issue.
I mentioned my findings in some motorcycle forums, but had only negative comments.
On the other hand I challenged each individual to apply the same techniques which they didn't want to (or dare to) apply; to see for themselves the benefits of it all.
I also heard some negative remarks concerning plug fouling; and I'm all for doing the research when I can!
I asked the very simple question, if they had ever seen a 2 stroke engine using a 50:1 ratio of 2 stroke in the fuel, and if that engine had suffered plug fouling?
No one did.
The ratio used in a 2 stroke is 2,5x more, so the fouling in a 4 stroke should be 2,5x less than in a 2 stroke.
Others mentioned smoke, and pollution.
While I can not defend pollution (not enough research material to record the emissions), I can say that smoke is a non issue for a 2 stroke engine running a 32:1 ratio of oil in the gas, or higher.
The 2 stroke weed eaters blowing white and blue smoke and suffering plug fouling, often times run at ratios well below the 32:1 ratio (or having more than 1 measure of oil per 32 measures of fuel), oftentimes done by people who don't know what they're doing; or accidentally double oiled the gas...
Another benefit is the valves. Not only do they close better (meaning less exhaust leakage, and lower engine temps), they also benefit from lower RPM (when taller gears are installed).
Lower RPM means lower wear on the valves. The valves don't suffer from the increase in engine load.
Some people mentioned engine lugging. While I firmly believe engine lugging is a non issue on this bike (even with 50% overgearing), some people still hold on that engine lugging could occur.
My response was, that engine lugging is more connected to riding style, than gearing.
Any sane person will not open the throttle in 5th gear, when going 15MPH. The same is true for any gearing, both stock gearing and modified gearing.
Once the Rebel hits 2,5k RPM, that engine does not lug.
However, I have noticed with a 50% increase in gearing over the stock gearing (from 9k rpm top speed, to 6k RPM top speed), that the engine does use more fuel going WOT, than with less heavy gears. Increased fuel consumption could be an indication of lugging. So they might be right there. Out of safety, I only go WOT, in 4th gear (second to last gear) on my Rebel, running at 7,5K RPM, where the engine has increased MPG over in 5th gear doing 6k RPM.
On the low RPM side, engine lugging happens below 2,5k RPM, and I never go there.
It's easy to shift down when necessary.
Last benefit is the fuel itself. With 2 stroke added, the gasoline will not only last longer (evaporates slightly slower), but it also will be heavier, meaning octane rating might rise.
In the past, gasoline companies used lead to increase octane levels, but 2 stroke oil also helps a bit. You're not going to make your 87 oct gasoline into a successful premium blend, but I do believe that 87oct gas could get upto 88 or 89 oct weight, causing less pinging on high compression vehicles, or vehicles running in high heat weather.
I see only benefits in adding 2 stroke oil, with the only con being exhaust emissions.
I would like to hear more pro's/cons of using this method. And people's experiences with it..
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