Mayot running problems with Brazilian fuel (30% alcohol) - HELP

[*Touring Ted*]

Does anyone have experience of running brazilian or alchol rich fuel ?????

Im currently in Brazil and having major running problems with my XT600E

It was running fine until I got here and started using the fuel (which is 30% alcohol)

The bike keeps cutting out and feels like its being starved of fuel. It will cut out when I open the throttle to accelerate or overtake trucks.. Sometimes it will just cut out in town and I have to wait a few minutes before it will start again.

Im travelling with 3 other bikes who although they are feeling the effects with poor starting and less power, they are not having problems like me.

I have just stripped the carb in my hotel room and all the jets, pipes clear and diaphrams in great shape (the bike only have 12000 miles). I have also changed the plug and the filter before hand which made no difference.

I am also getting 30% better fuel economy so my guess is that the alcohol is making the bike run very lean.

Im going to change the clip pósition on the jets and try and richen her up top see if it makes a difference.

Im all ears to suggestions.

[bacardi23]

I've heard of people putting more octanes in their fuel...duno if it is a good ideia or not...

How was Buenos Aires?

[bruken]

I have no experience of Brazilian feuls.

I have some experience of Zimbabwe alcohol rich feuls. But there if you could just get fuel you were made; so...

Firstly you dont want to add octane boosters. Alcohol / Ethanol tolerates much higher compression levels than fossil fuel.

Ethanol burns much hotter. (Timing may be of issue) For once praise to fuel injection over Carbs :-(

Ethanol will probably eat your rubber components. Ethanol is highly corrosive that way. Tolerance of rubber to EU or common standards is only 10% mix.

Brazil runs "Flexifuel" vehicles. Your bike is probably not.


The calorific value of Ethanol is 55% lower than fossil fuel. Running a "richer mix" is probbly your best answer alongside a hotter spark plug. Watch your engine temp.

[bruken]

some more info.

Quoted from Alcohol for Motor Fuels

Blending Alcohol and Gasoline
Mixing alcohol with gasoline produces gasohol. Advantages of fuel blends are that alcohol tends to increase the octane rating, which is particularly important in unleaded fuel, and reduce carbon monoxide (CO) emissions from the engine.

The primary disadvantage of mixing methyl and ethyl alcohol with gasoline is that under certain conditions these alcohols may separate from the gasoline. An engine adjusted to burn gasoline efficiently will produce less power from alcohol should it separate from the gasoline. Separation is caused by the polar nature of the alcohol molecules and their tendency to absorb water, also a polar substance. Methyl alcohol is the most likely to separate, butyl alcohol the least likely. The tendency for separation increases as the temperature decreases, the quantity of water absorbed increases, and the quality of the gasoline decreases.


Figure 2: Gasoline engine full throttle exhaust emissions using ethanol fuel blends.

The effect of using a blend of alcohol and gasoline in an engine adjusted for gasoline is to "lean out" the fuel mixture. This is illustrated in Figure 1 for an engine burning blends of ethanol and gasoline. A mixture of 10 percent ethanol in gasoline produced more power when the carburetor was adjusted for gasoline. Increasing the ethanol content to 25 percent reduced the power output. The test results in Figure 1 were obtained at an elevation of 5,000 feet where an engine adjusted to operate on gasoline is expected to run rich. The 10 percent blend produced a leaner and better air-fuel ratio; the 25 percent blend was too lean.

Because of its higher stoichiometric air-fuel ratio, butyl alcohol can be mixed with gasoline in higher concentrations without affecting performance. Similarly, because of its low stoichiometric air-fuel ratio, only a small quantity of methyl alcohol can be mixed with gasoline without affecting performance. In other words, a fuel blend containing 20 percent methyl alcohol requires modification of the carburetor fuel jets to optimize power output, whereas a 20 percent blend of butyl alcohol does not.

The effect on exhaust emissions of increasing the ethanol concentration in the fuel is shown in Figure 2. The primary effect of ethanol is to reduce the CO emissions. It should be noted that the same effect was obtained using straight gasoline and carefully leaning the air-fuel ratio.

[bruken]

Further reading

Adapting your engine for ethanol

[*Touring Ted*]

Thanks for the info....

The bike actually runs much worse in the wet too here.

So, iv richened up the secondary carb and ill post back my results...

Working on carbs in a hotel room in tropical heat with a limited tool kit is surprisingly difficult and frustrating

[*Touring Ted*]

Thanks Bruken, loads of useful infor there to help me sort this !!

[yhprum]

Did it run better with the choke on? That would enrichen the mixture, at least for troubleshooting.