50:1 VERSUS 33:1

[awac]

I found this article interesting and would be interested to hear views and if anyone has experienced problems similar and relating to the premix ratio.


Article at http://www.sweller.co.uk/mz/articles/mz_eco.html

A few years ago "Motorcycle Rider", (the British Motorcycle Federation magazine), ran a series of articles on the "Eco Worthiness" of various machines. I have reproduced the bulk of the MZ related one.

Stephen Kearney wrote:
The MZ Supa 5 (TS 250/1) came out in 1975. This was the first bike that got MZ accepted as a serious contender, at least as far as we are concerned. Before that their decidedly odd shape and apparent irrelevance seemed to sideline them to the more eccentric end of the bike market. While one might complain about the looks of the Supa 5 also, I find its functional style quite attractive. Maybe I'm just joining the eccentrics.
Although never having owned one, I have some knowledge of the Supa 5, having shared a flat with twin brothers who operated one apiece as dispatch riders for five years. Further, more information was offered by another DR with a 1989 ETZ 250, bored out to 300cc.

Road tests at the time generally reckoned that it was quite good for what it was and particularly commended its bright lights, despite being only six volts. One magazine said they were so good they didn't need 12 volts.
Over the next few years they gradually became more popular and by 1978-1979 they were considered one of the more serious dispatch bikes. But even then rumours were beginning to circulate about dodgy main bearings.

For reasons best known to himself, Twin No 1 decided to go dispatching and in 1979 bought himself a new Supa 5 for about £500: all black and chrome, just like a Vincent (ahem). It seemed like an excellent bike right from the start, and we couldn't believe how bright the lights were. The whole bike displayed a quality of functional concept and execution and was pleasurable to ride too.
It might have been simple but it was also refined.
If you need this point demonstrated, try a CZ 250 from Czechoslovakia, a country then operating under the same socio-economic system as the former East Germany. The CZ was of similar specification: 250cc two-stroke single, petroil mix, intended for rugged transport. You'd imagine therefore that the two machines would be pretty similar to ride: not a bit of it. The designer of the CZ clearly intended that nobody should ever get any pleasure out of riding it - and he succeeded!

Twin No.2 decided to follow the family career and bought an 11,000-mile Supa 5 for around £200. Both twins then dispatched merrily away.

At 14,000 miles the main bearings on twin 1's MZ gave up, signalled by a very noisy engine. So the rumours were true! Folklore at the time suggested that poor quality East German (some even said Russian) bearings were the reason. Mind you, I knew a chap who got all of 2,000 miles out of a brand new Norton Commando before its mains failed, in Paris.

We decided to try British bearings and these were duly installed. They failed at 16,000 miles; so much for folklore. We had to try something different.

The recommended petroil mix for the Supa 5 is 50:1, which is remarkably lean for a simple two-stroke. My old Bantam, for instance, used to run on 20:1 and smoked to prove it. A friend who used to run his Lambretta on 16:1 suggested 33:1 for the MZ, so this was tried along with another set of British mains. That set was still going strong when the bike was sold 60,000 miles later.

Twin 2 had a similar story. His mains failed at 13,000 and the selling dealer, an MZ agent, was baffled, particularly as the engine sounded so well at 11,000. New bearings were installed and a switch made to a 33:1 mix. No further bearing problems were encountered and the momentary piston seizures that occurred from time to time on the old mix ratio now disappeared.

Some suggested it was the West's pollution laws which forced the MZ factory into recommending such a lean mix, but when I checked in the MZ shop in East Berlin in 1982 they told me that the recommended mix for them was 50:1 too. When I recounted our experiences, they were stumped. They had never heard of dispatch riders, by the way.

For general running and dispatching, both Supa 5s were well up to the job, providing reliable service under rough conditions with patchy and amateurish maintenance.
The big weaknesses were the electrics and the front brakes. Despite the glowing (no pun) account above, the electrics were just not up to the job, providing weak lights and virtually no horn - an almost fatal combination for dispatching. I can only assume that a combination of continuous town running and accumulated dirt and corrosion in the wiring harness caused the lights to fade from their original brilliance.

The single leading shoe front brake wasn't strong enough for city dispatch work; in fact, both twins complained that it was downright dangerous. The Supa 5 remains, however, the most rust-resistant bike I have ever seen.

The shortcomings mentioned above have been largely overcome with the ETZ250, which boasts a disc front brake and 12-volt electrics. With over 30,000 miles, no main bearing faults were reported. It has an autolube system but I'm not sure if this is the reason.

[mark h]

exellent article, thanks. Although my ts 125 is only used for weekend rides and certainly not dispached, I think I'll stick to 33/1, as you cant over lubricate a bearing, and hope my spark plug doesn't get soiled.
Just a thought , but what was the quality of the 2 stroke oil in the late seventies, my kawasaki had an oil pump, similar to an ETZ, and mains going, and pistons siezing, wasn't unheard of on kawasaki 2 strokes.

[awac]

Hi Mark,

Very valid thought, the quality of oils. I know an ex Kawasaki dealer from the 70s so I will ask him about his experience when I chat to him next.
A very interesting article on http://www.dansmc.com/2stroke_oil.htm he does some great stuff on his web site, have a look around it. He is also questioning individual oil manufactures standards and the oils ability to dilute (this is all going to get very technical soon, I can see that...). I believe his reference is competition 2-strokes at 20:1.

2-STROKE OIL
I'll condense hours and hours of study and research to one statement. "You can run the manufactures oil at whatever ratio the manufacture says and feel safe. ANY other oil run at 20 to 1."(20 parts gas to 1 part oil) .In other words run Honda oil in Honda 2/strokes at Honda ratios. But if you run Honda oil in a Yamaha, run it at 20/1. Yamaha oil in a Honda? Same thing 20/1. They all say "Ours is the finest oil available." Trouble is they will not really tell you why.
FOLLOW THE ABOVE RULE

If You Don't.... It's OK.... I Don't Care.... It's Not My Engine!!!!
Now, I know a lot of you out there who feel you can run things much leaner. Like 32 to 1 or 40 to 1 or even leaner. No less an expert than Bob Greene recommended a 32 to 1 mix and no less an expert than Gordon Jennings recommended a 20 to 1 mix. A lot of people run lean and a lot of them get away with it... and a lot of them don't. So what gives ? I feel the problem is this. No one really knows at what dilution the 2-stroke oils are mixed at or exactly what additives are added. At least I don't, and I've tried to find out a number of times. They send you a bunch of specs but will only say "Ours is the finest available." They never say why their $3.00 a quart oil is better then the $5.00 a quart stuff. Here are a few ideas to consider.

Let's look at dilution. At least that's my word for it, and I don't really mean the weight of the oil either. Most say they are a 30w. I mean the ratio of the stuff that counts to the stuff they put in to make it look and mix good. That make sense ? Probably not ! Well, think of it this way. If oil "A" is twice as thick as oil "B" and you mix both at 40 to 1, oil "A" will really be 20 to 1, right ? Now think about the reverse. If "A" is half as thick as oil "B" and you mix both at 40 to 1. "A" would now be 80 to 1. A bit lean right ? I don't think the real dilution ratios, between different oils, are that big. I do think there is enough of a difference between 2-stroke oils to cause a problem. Especially when you consider the additive package.

What about additives ? I think the manufacturers match the additive packages to the metallurgy of the metals in their engines. I once went to a Lawnboy lawnmower school where they bragged that the Lawnboy oil had almost no ash in it. They said this was really good for their engines. Another mechanic at the school said he had been to a Sachs chainsaw school and they told him there that the Sach engine needed ash. Their oil had lots of ash. Seems to me he said at least 2-3 % of ash, yet Lawnboy likes almost nothing... Why ? What about the other additives in the package ?

Here are some more things to consider. Most 2-stroke, motorcycle engines have fixed carb jets. This means changing the ratios will change the air fuel mix as oil is not gas ! Change the ratios and you may need to rejet the carb.

I have noticed that as an engine wears out the quality of its combustion declines. In other words it does not burn the fuel mixture as good as it once did. ( Well Duh ! ) As oil does not burn as good as gas, your plug tends to oil foul. Also, a worn engine will have worn seals too, letting oil in from the transmission. Now, you tell me. Do you maintain your Race Bike ( and that CR, RM, KX, YZ, etc, IS a full blown Race Bike ) to factory standards ? Do you know what those standards are ? You know... new rings every 3 motos, and all that other stuff ? Hint... they are in your shop manual.

My point is this. With 20 to 1 you will get enough of what ever is needed to keep your engine running, no matter what the manufacturer wanted. When your buddies say run 40 or more to 1 on your oil, watch out ! They may mean well, but what will it do to your bike over the long run ? Are you running 40-50 to 1 ? I know of no scientifically run tests that show less oil is better for your engine. On the contrary, I know of several that show more oil, jetted right, in a good engine, gives more horsepower. If your engine does seem to run better on less oil, you just might need to rejet, rebuild, or retune. If you insist on running lean on the oil, you better have done your homework !

One thing I do know... the worst thing that's going to happen to your engine at 20 to 1 is a fouled plug and maybe your spark arrester screens plugging up. Too lean and...

Now, if any of you oil manufacturers care to enlighten me with some facts and tests, it would sure make me happy if you would do so.

[awac]

Cycle Magazine February 1978. Downloaded from http://www.bridgestonemotorcycle.com/do ... remix6.pdf

They test the premix theory, less is more and conclude "and it let us shoot a couple of big holes in less-is-more Miracle-Oil trendiness. Less, in the context of premix lubrication, isn't more; it's less, just as logic always insisted".

[awac]

Ok, let me take the study a little further, once you have decided on your ratio after reading Cycle's 1978 findings (do you know of any more recent reports?) you fill up at your local petrol station with petrol which now contains ethanol, how does that react with the 2stroke oil your mixing? At present many filling stations in the UK have 5-10% ethanol in their petrol, so you are probably using ethanol without realising it. This is called E5 (5% ethanol 95% petrol) or E10 (10% ethanol 90% petrol).

http://www.bp.com/assets/bp_internet/.. ... ochure.pdf
BP Australia 2-stroke fuel guide. "How to premix your own 2-stroke fuel".

While new BP Unleaded 91 with up to 10% renewable ethanol is great for most cars, we don’t recommend it for use in 2-stroke engines without first consulting with your engine manufacturer. This is because

• Ethanol-blended fuel contains higher oxygen content and some small engines, such as chainsaws and whipper snippers, aren’t able to compensate for the increased oxygen in the fuel mixture.
• Different engines have different fuel requirements and some older engines are not suitable for fuels containing ethanol. So, always check with your engine manufacturer before use.
• Ethanol-blended fuel is incompatible with some carburetted engines.
• Ethanol-blended fuel may soften plastic and fibreglass components in your fuel tank, causing them to leech
resin and damage filters and injectors.
• In marine environments, water from condensation may collect in fuel tanks. This water can cause ethanol to separate from
the rest of the fuel and sink to the bottom of the tank. This process, known as phase separation, can lead to poor engine
performance or breakdown.
• Spillage of ethanol-blended fuel onto your equipment’s paintwork may cause blistering

http://www.rotaxservice.com/rotax_tips/rotax_feed2.htm
Feeding your Rotax 2-Stroke Aircraft Engine
Certain fuels contain alcohols such as ethanol. These ingredients should be avoided since they absorb water which then creates corrosion inside a 2-stroke engine. They also have the effect of reducing the oil's lubricating properties. Rotax recommends avoiding fuels containing more than 5% alcohol.

[awac]

Attached a Study of bioethanol FYI.

Anyway in the last post did you notice the line
"Ethanol-blended fuel contains higher oxygen content and some small engines, such as chainsaws and whipper snippers, aren’t able to compensate for the increased oxygen in the fuel mixture"
Then
"Certain fuels contain alcohols such as ethanol. These ingredients should be avoided since they absorb water which then creates corrosion inside a 2-stroke engine. They also have the effect of reducing the oil's lubricating properties. Rotax recommends avoiding fuels containing more than 5% alcohol".
And I finish with
"At present many filling stations in the UK have 5-10% ethanol in their petrol".

"My dear Watson, I deduce a lean mixture with a reduction of lubricating properties, dam that foul Moriarty with his plan to eradicate all the classic vehicles with the millennium bioethanol bug!"

[awac]

Fuel additives.
Have you used them, do you find any difference? Where do you stick the extra bottle....? Here are some examples with information/claims.

Millers Oils VSPe Power Plus 250ml petrol additive
Millers Oils VSPe Plus is an all in one protection ethanol-lead replacement octane improver. It is recommended for all classic engines previously requiring leaded fuel.
Recommended for all classic engines previously requiring leaded fuel and now running on unleaded fuel. Adds up to 2 octane numbers to unleaded fuel. Prevents valve seat recession when used with unhardened valve seats. Prevents detonation, hot spots and running on. . Prevents fuel system corrosion/helps protect components. Combats the adverse effects of ethanol in fuel. Carburettor anti icing formula. Contains anti oxidant to improve fuel life.
It is one of three new fuel additives from Millers Oils launched to protect classic vehicles from rising ethanol content in unleaded fuels.

Eastwood Fuel Guard
Lawn mowers, chain saws and marine engines are examples of 2-stroke engines. In these cases, the moisture caused by Phase Separation, will compete with the blended oil for bonding to metal engine parts. The engine will be robbed of lubrication and severe damage could occur. Additionally, rubber and plastic fuel system components can be permanently damaged. “Ethanol blended in gasoline actually attracts water. This causes the water and gasoline to separate, producing Phase Separation. Phase Separation can create severe fuel system damage. Once it has taken place, it presently cannot be reversed,”

Bell Mix-I-Go Small Engine Formula
What's more, 2-cycle engine equipment users have found that ethanol blends draw water in the fuel, preventing the essential fuel-dissolved oil from delivered needed lubrication to critical metal parts that rely on the fuel-oil mixture for lubrication and proper functioning. This leads to equipment damage and small engine failure from lack of essential lubrication.

[awac]

In the discussion of the oil premix ratio, Phase separation has to be included. Could it be causing premature wear whatever your chosen mixture to a number of engines? Is it in fact just as important as the mixture to consider? Is there a 2 stoke oil which contains anti ethanol properties already mixed?


Fuel Phase Separation in Ethanol Blended Gasoline?
http://www.enertechlabs.com/fuel_phase_ ... thanol.htm
Courtesy of Scott Irwin
Did you know? In a 10% Ethanol Blend, it takes as little as 18 gallons of water in a 6,000 gallon tanks to cause Phase Separation. In a 2% blend it takes only 3.6 gallons to cause Phase Separation

What is ?phase separation?, and how do I deal with it?
If significant amounts of water are present in a fuel tank with gasoline that contains ethanol, the water will be drawn into the fuel until the saturation point is reached for the three-component mixture of water + gasoline + ethanol. Beyond this level of water, phase separation could cause most of the ethanol and water to separate from the bulk fuel and drop to the bottom of the tank, leaving gasoline with a significantly reduced level of ethanol in the upper phase. If the lower phase of water and ethanol is large enough to reach the fuel inlet, it could be pumped directly to the engine and cause significant problems. Even if the ethanol water phase at the bottom of the tank is not drawn into the fuel inlet, the reduced ethanol level of the fuel reduces the octane rating by as much as 3 octane numbers, which could result in engine problems.

The level at which phase separation can occur is determined by a number of variables, including the amount of ethanol, the composition of the fuel, the temperature of the environment and the presence of contaminants. It is very important (A) that the system is inspected for significant quantities of water in the tank before using gasoline with ethanol and (B) to limit exposure of the fuel tank to excess water. If phase separation has occurred, it is necessary to completely remove all free water from the system and replace the fuel before continuing operation. Otherwise, engine problems could occur.

Does ethanol affect horsepower or fuel-efficiency?
Ethanol has a heating value of 76,000 BTU per gallon, which is approximately 30 percent less than gasoline's heating value (which is approximately 109,000 to 119,000 BTU/gal). The result is E-10 gasoline should yield slightly lower mileage ? a decrease of approximately 3 percent. Fuels containing higher levels of ethanol will have a corresponding reduction in mileage. For example, E85 fuels produce mileage approximately 30 percent less than gasoline.

What are the characteristics of ethanol?
Ethanol is an oxygenated hydrocarbon compound that has a high octane rating and therefore is useful in increasing the octane level of unleaded gasoline. The EPA, the agency responsible for setting some of the requirements for all gasoline used in the U.S., has allowed the use of ethanol in gasoline at levels up to 10 percent as an octane enhancer and as an oxygenate to provide beneficial clean-burning combustion characteristics that help improve some emissions.

Ethanol is hygroscopic (it has an attraction for water) and will more readily mix with water than with gasoline. It has different solvency behaviors than does gasoline, which allows it to loosen rust and debris that might lay undisturbed in fuel systems. And it can more readily remove plasticizers and resins from certain plastic materials that might not be affected by gasoline alone. Loose debris will plug filters and can interfere with engine operation. Additionally, ethanol is corrosive to some metals, especially in combination with water. Although gasoline does not conduct electricity well, ethanol has an appreciable capability to conduct electricity and therefore can promote galvanic corrosion.

Two Stroke Engines

Phase Separation in ethanol-blended gasoline, however, can be more damaging than in MTBE blends and straight gasoline. When phase separation occurs in an ethanol blended gasoline, the water will actually begin to remove the ethanol from the gasoline. Therefore, the second phase which can occur in ethanol blends contains both ethanol and water, as opposed to just water in MTBE blends and conventional gasoline. In the case of two-stroke engines, this water-ethanol phase will compete with the blended oil for bonding to the metal engine parts. Therefore, the engine will not have enough lubrication, and engine damage may result.