Petrol and ethanol

[MR BIKER]

Hi All: I just made a surprising discovery which if you google, my founding is actually not new. Because of economy, I like almost everyone go JB to fill up. Have you ever wonder why we must fill up only 97 by the authorith there?? Well, I just found out that , there is almost a high chance they add a high amount of ethanol (alcohol) into their RON 97. Say if you fill 20 litres, you pay that amount but get the same volume but lesser fuel because ethanol which gives the volume, doesnt actually push the bike far and powerfull enough. NO wonder my bike get very low fc.

 

To test this, I fill full RON 92 with same company but here in Singapore. I get better mieage. QUESTION: WHICH ON TO GO??? JB LOWER PRICE BUT LESS MILEAGE AND BUT POWER OR SPORE MORE MILEAGE BUT LESS POWER. YOU DO THE MATHS. OH i think this apply more for class 2 or big bikes.

[BLACK COMET]

Nope. The last round I check their composition, they still use MTBE.

Petrol with alcohol is know as Gasohol in USA. Marketed as e85, e90,e95.

Meaning:

 

e85 = 85% petrol, 15% ethanol. 90 is 90% petrol. and etc.

 

Most oil company will need to declare this as e85 is not suitable for all engines. The first thing to go will be seals and fuel lines.

 

I think alot the vehicles in whole of SE asian is not design to run any of the alcohol and gasoline mix.

 

Their reason why foriegner is not allowed to buy 95 and below is that they don;t want to subsidies foriegners. simple as that.

 

The reason for u r poor fuel consumption.

 

Are u using 92 most of the time and occasionally 95?

 

If yes, Just try the following

 

try to pump a 50% 95 and 50% 98.

Then do a full servicing, Carb wash, air filter change, oil change and carb tune.

 

Then chances that the 97 JB fuel will give u better economy.

 

But after doing that, ur bike will perform poorly

on 92.

[Pandoras Kitten 3]

Heard that in Thailand they are using gasohol almost exclusively since early last year. Bad news for owners of older machines as the e series fuels may be corrosive.

 

Benzene must be used for older vehicles there and it's getting rarer and rarer.

 

Sent from my hong kong gangsta phone using Tapatalk

[KeraKing]

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If yes, Just try the following

 

try to pump a 50% 95 and 50% 98.

Then do a full servicing, Carb wash, air filter change, oil change and carb tune.

 

Then chances that the 97 JB fuel will give u better economy.

 

But after doing that, ur bike will perform poorly

on 92.

 

good info on the fuel.

 

anyway can explain why the bike will perform poorly on 92? thanx.

[yc86]

Ethanol has a relatively high octane number, if I'm not wrong it's around RON105. But it's disadvantage is it's specific energy content, which is something like 28MJ/kg compared to ard 44MJ/kg for petrol. So the higher percentage of ethanol u have, the lower your mileage will be. But u will be giving off less harmful emissions per km than using petrol.

[MR BIKER]

Good expalanation. And depending on the bike and heat dissipiated by it and its nearness to the engine, ethanol will vapourise much faster compared to petrol , so after going the same distant but if have more stops because of traffic lights or jam, the one with more ethanol will cause our bike to go to the petrol station more often.

[BLACK COMET]

good info on the fuel.

 

anyway can explain why the bike will perform poorly on 92? thanx.

 

This one is personal experience.

 

First bike needs 95. But I only pump Vpower all the way back then. So never notice about that. But it was the first bike that I learn abit of carb tune. First bike idle too high. tune it donw it will back fire. so I learn how to tune the pilot screw from friend. anyway, that bike is famous for that. design flaw. only the second batch of bike that they solve the problem with a different exhaust.

 

The next bike 1 got is using a cvk24. as usual, brand new bike idle is high. but since I know how to tune. So tune it as according. inital idling was 2K. alittle high. so tune it down to 1.6K. pilot screw is at 2 and 1/8 on 98. Vpower is also around there. very minute diff.

 

Then the period where petrol price rise from 1.4 to 1.8. I use 95.

Upon using that, I notice engine not as smooth and FC goes down abit. retune the carb for 95. I need to set at 2 and 1/4 turn.

 

As petrol rise to 2.5 back then I switch to 92. This is the worst I have exprience. Althou my bike can take 92.

The throttle responds and smoothness was horrible. I have to retune again. for 92. it have to be 2 and 1/2 turn.

 

All this means that all petrol grade need slight changes to the carb tuning.

 

Assuming ur bike is stock. U have to make sure the tune state is right. too rich or lean will affect ur fc.

 

other variables like chain, tire pressure, batt condition indirectly will affect it.

 

Also carb tuning in day time and night time will be diff also.

[Pandoras Kitten 3]

Also carb tuning in day time and night time will be diff also.

 

Yep, I always have to resort to explaining how to fly a piston engined aircraft * to get people to understand how to tune their carbs for that sweet spot

 

Suffice to say bike is never tuned correctly in the shop, even if it starts and idles well enough - the engine needs to be warmed up before any carb tuning is done for it to run best.

 

* = the more simple piston engined planes have manual air/fuel mixture controls. Mixture settings are different if a/c is at takeoff power, cruising, hot or cold ambient temp etc.

 

Speaking of 92 octane - I have no idea why but my Yamaha 125Z seemed to run best on Esso 92. Could it be the super low compression ratio of 6.5:1?

[BLACK COMET]

Yep, I always have to resort to explaining how to fly a piston engined aircraft * to get people to understand how to tune their carbs for that sweet spot

 

Suffice to say bike is never tuned correctly in the shop, even if it starts and idles well enough - the engine needs to be warmed up before any carb tuning is done for it to run best.

 

* = the more simple piston engined planes have manual air/fuel mixture controls. Mixture settings are different if a/c is at takeoff power, cruising, hot or cold ambient temp etc.

 

Speaking of 92 octane - I have no idea why but my Yamaha 125Z seemed to run best on Esso 92. Could it be the super low compression ratio of 6.5:1?

 

6.5:1? 2 stroke?