A Fuel Question?

[kalbo]

Living in the Philippines, most of the forecourts offer a choice of either 91 regular or 95 premium. Some also have 97. All the fuel here has an additive of 10% ethanol. Unfortunately, they add a horrible red dye to the fuel which causes carb contamination problems over time. Since I have owned my Max I have been using 95 and occasionally 97 when I find it.
I was talking to a guy who has owned a couple of Max's over here and he has told me that the Max is better if run on 91, as that is what they were made to run on, mine is a 1986. I have just swapped to 91 and it seems to be running fine. Does anybody else agree with this guy? I thought higher octane=better performance?

 

[MaxMidnight]

Perhaps it would help if you understood what the octane number means.

As the air/ fuel mixture is compressed there can come a point where it will self ignite. This is not good.

To prevent this fuel, companies put additives in to prevent this happening; the higher the octane number the greater the resistance to pre-ignition.

One of the side effects of these additives is that the rate of burn of the mixture slows down.
This is not significant if you have improved the efficiency of the motor by raising the compression ratio.
However, if your motor is designed to run on (say) 91 octane then using a higher value would, in theory, reduce the power output.
By how much I know not but probably only a few percent.

Some of the higher octane fuels sold in the UK claim other benefits such as cleaner engines and better fuel consumption.
I'm guessing that this is due to other additives. On the few occasions I've used it in my bike I can't say I've noticed any benefit.

In summary, in a standard motor you will not get any benefit from higher octane fuel but it won't do any harm.
If the higher octane fuel is more expensive than the recommended fuel then it is your wallet that will suffer.

 

[davesax36]

It runs on 87...midnight knows his stuff.

Sent from my STV100-2 using Tapatalk

 

[caseyjones955]

I use the lowest octane rating I can find without ethanol, which here is usually 91. If I can find 87 pure gasoline it seems happiest, although I have no hard data to back that up. In SD we still have 85 at many pumps and I dont go that low on the bike although I had to put it in a couple times (thanks to an impaired cruising range) and it seemed to work fine.

Im not sure how US octane ratings coincide with those in the PI but i see absolutly no benefit to using "premium" in either my Venture or Vmax here in the US.

 

[Jan Bee]

I use the lowest octane rating I can find without ethanol, which here is usually 91. If I can find 87 pure gasoline it seems happiest, although I have no hard data to back that up. In SD we still have 85 at many pumps and I dont go that low on the bike although I had to put it in a couple times (thanks to an impaired cruising range) and it seemed to work fine.

Im not sure how US octane ratings coincide with those in the PI but i see absolutly no benefit to using "premium" in either my Venture or Vmax here in the US.

Higher octane fuel only helps higher performance engines.
Use the lowest rated possible fuel that will prevent knocking.
Yamaha actually says 89.

 

[D-Max2012]

The Clymer V-max 1985-2003 Service * Repair * Maintenance manual states regular unleaded with no higher than a 10% Ethanol rating.

 

[SpecOps13]

I have some vehicles that need higher octane and keep a supply of 91 octane Non-Ethanol here in cans. VMax's other than my high compression 89 will run on lower octane ratings just fine.

 

[KJShover]

Perhaps it would help if you understood what the octane number means.

As the air/ fuel mixture is compressed there can come a point where it will self ignite. This is not good.

To prevent this fuel, companies put additives in to prevent this happening; the higher the octane number the greater the resistance to pre-ignition.

One of the side effects of these additives is that the rate of burn of the mixture slows down.
This is not significant if you have improved the efficiency of the motor by raising the compression ratio.
However, if your motor is designed to run on (say) 91 octane then using a higher value would, in theory, reduce the power output.
By how much I know not but probably only a few percent.

Some of the higher octane fuels sold in the UK claim other benefits such as cleaner engines and better fuel consumption.
I'm guessing that this is due to other additives. On the few occasions I've used it in my bike I can't say I've noticed any benefit.

In summary, in a standard motor you will not get any benefit from higher octane fuel but it won't do any harm.
If the higher octane fuel is more expensive than the recommended fuel then it is your wallet that will suffer.

I love your posts, Its like a mini class in every one :clapping: