Intruders-Alert

What I do is reduce octane until pre-ignition ping occurs, then bump it back up to the next level.

I have never run anything but 87 in my RSTD and have 60k on it. I also run Seafoam occasionally and the bike runs great. It is completely stock other than Harley pipes. It makes 100 hp and doesn't need any jets or mods. If you have a Jap bike and are running anything but 87 your wasting money but it's your money to waste.

Hunter wrote: If you have a Jap bike and are running anything but 87 your wasting money but it's your money to waste.

Makes sense to me ...
I also agree about the sea foam.

if you run premium in a vehicle that requires regular , all you are doing in building up carbon in your engine.

many small planes do not require 100 octane...so at run up you lean the crap out of the engine and run it for a while to burn the carbon off of the plugs. ( most of that is due to students scared to lean the engine above 3000 feet )

I cant buy shit fuel here in Thailand its either 91 or 95 or E20.

The 1400 does not like E 20 back fires like a bastard on start up, --but my suzi 110 2 stroke loves it.

The 1400 must have its 91 but it does like a bit of paraffin wich is what Seafoam is. Well a bit of Jet fuel A 100 too a very detergent fuel which cleans your finger nails great.

High octane is not high explosive its the other way round, the higher the octane the higher compression ratio you can run because the fuel will not explode until the spark.

High octane was doped with lead but that is not allowed any more. The old Dakota's used 110 octane, ran great in my Jag.

Over here we can get real naphthalene mothballs. Running 91 ethanol and 4 balls (ha ha) every few fill ups and the bike runs great. Carbs are real clean and no carbon build up on the piston crowns and rings. I just fitted new head gaskets to my old girl, '85 750, damn I was so surprised at the lack of black crap in the bang department.

[emoji41]

Fred wrote:I cant buy shit fuel here in Thailand its either 91 or 95 or E20.

Is that the same as the European standard rating? In the US, the numbers are from the equation (R+M)/2, so our numbers are always lower than EU numbers, as they use the R by itself. Typically, the US rating is 3-5 points lower than the EU standard.

WintrSol wrote:

Fred wrote:I cant buy shit fuel here in Thailand its either 91 or 95 or E20.

Is that the same as the European standard rating? In the US, the numbers are from the equation (R+M)/2, so our numbers are always lower than EU numbers, as they use the R by itself. Typically, the US rating is 3-5 points lower than the EU standard.

I have no Idea ;IDunno:

Lechy wrote:Over here we can get real naphthalene mothballs. Running 91 ethanol and 4 balls (ha ha) every few fill ups and the bike runs great. Carbs are real clean and no carbon build up on the piston crowns and rings. I just fitted new head gaskets to my old girl, '85 750, damn I was so surprised at the lack of black crap in the bang department.

[emoji41]

Engines just don't coke up like the old days, de coke ing is no longer heard of. leaded fuel used to smoke black(soot) ever tried it in a petrol lighter,--it would smoke like hell and your cigarette would be black-- Thats why you had to buy lighter fluid.

Fred wrote:

WintrSol wrote:

Fred wrote:I cant buy shit fuel here in Thailand its either 91 or 95 or E20.

Is that the same as the European standard rating? In the US, the numbers are from the equation (R+M)/2, so our numbers are always lower than EU numbers, as they use the R by itself. Typically, the US rating is 3-5 points lower than the EU standard.

I have no Idea ;IDunno:

I just Googled it, and, according to Wiki (always correct, no? ) Thailand uses RON, the R in my equation, so your 91 is about equal to our 87 (more or less).

Leckbass wrote:My buddy and I were going to ride quads this weekend, he refused to put regular gas in this quad, so we wasted an hour looking for race fuel, then he settled on Ultra 94.

I told him that he's being ridiculous and that the quad should run on 87.

So tired of arguing this "premium" gas myth.

run a higher octane then needed...you are building carbon deposits in your engne.


airports have 100/110 low lead gas. Many small planes do not need that high octane...( also students not leaning engine when at altitude ) so at run up ( as instructor taught me ) would lean the crap out of the engine to burn carbon off of the plugs. you get it so lean that the engine is running rough..then as carbon burns off, she starts to smooth out .

there is a reason the company gives an octane rating for engines...

After owning diff models of Bikes and the Forum debate about octane. I came across a great article, now I can't find it. HERE IS WHAT I REMEMBER. all engines with 12.5 COMPRESSION RATIO. use premium fuel. 96 with Advance spark due to the slower burn of the fuel. my 98 caddie said so on the fuel CAP. I RAN 87 Octane all the time. the onboard computer changed the timing so it ran fine. I bought a 2005 Busa that the salesman took to fill up with gas for me. came back and he said he went to Sunoco and filled it with 100 Octane racing fuel. I insisted they drain the tank and fill it with 87 O.

NOVEMBER 2001 BY FRANK MARKUS
Regular or Premium?
There's no shortage of opinions on who is to blame for gas-price gouging. One thing that's certain is drivers tend to economize at the pump during extreme price rises-they buy cheaper, lower-octane gas.

In the old preelectronic days, cars would protest such parsimony by pinging like a pachinko parlor, but most modern cars don't complain audibly, so maybe they don't mind. Or do they? And conversely, is there any benefit to be had by springing for the expensive stuff when you're feeling flush?

To find out, we ordered a fleet of test cars-some calibrated to run on regular, others that require premium-and tested them at the track and on a dynamometer.

But before we go into the results, let's go to combustion school. When a spark plug fires, it does not cause an instantaneous explosion of the entire cylinder's charge of fuel and air. The spark actually lights off a small kernel of air-and-fuel mixture near the plug. From there, a flame front expands in every direction, gradually igniting the rest of the air and fuel. This takes some time, as much as 60 degrees of crankshaft rotation.

Meanwhile, the air-and-fuel mixture that the flame front has not yet reached is experiencing huge increases in pressure and temperature. If any part of this air-and-fuel mixture gets heated and squeezed enough, it will explode spontaneously, even before the flame front ignites. This self-ignition is called detonation, or the dreaded "knock."

Now for the chemistry lesson: Oil is a hydrocarbon fuel, meaning the individual molecules contain carbon and hydrogen atoms chained together. Modern gasoline is blended according to various recipes, the active ingredients for which include about 200 different hydrocarbons, each with a spine of between 4 and 12 carbon atoms. One of them, isooctane, consists of 8 carbon and 18 hydrogen atoms (C8H18) and is exceptionally resistant to exploding spontaneously when exposed to the heat and pressure found inside a typical combustion chamber. Another, n-heptane (C7H16) is highly susceptible to such self-ignition.

These two compounds are therefore used to rate the knock resistance of all gasoline blends. A gasoline recipe that resists knock the way a mixture of 87-percent isooctane and 13-percent n-heptane would is rated at 87. Racing fuels with octane ratings over 100 resist self-ignition even better than pure isooctane. The octane ratings for regular-grade fuel range from 85 to 87, midgrades are rated 88 to 90, and 91 and higher is premium.

Mind you, premium fuel does not necessarily pack more energy content than does regular. Rather, it allows more aggressive engine designs and calibrations that can extract more power from each gallon of gasoline.

An engine's tendency to knock is influenced most by its compression ratio, although combustion-chamber design also has a large effect. A higher ratio extracts more power during the expansion stroke, but it also creates higher cylinder pressures and temperatures, which tend to induce knock. In supercharged engines boost pressure behaves the same way. That's why the highest-performance engines require higher-octane fuel.

If you feed such an engine a fuel with insufficient octane, it will knock. Since it is impossible, for now, to change an engine's compression ratio, the only solution is to retard the ignition timing (or reduce boost pressure). Conversely, in some engines designed for regular fuel, you can advance the timing if you burn premium, but whether this will yield additional power varies from engine to engine.

Knock sensors are used in virtually all new GM, Ford, European, and Japanese cars, and most DaimlerChrysler vehicles built today. According to Gottfried Schiller, director of powertrain engineering at Bosch, these block-mounted sensors-one or two of them on most engines and about the size of a quarter-work like tiny seismometers that measure vibration patterns throughout the block to identify knock in any cylinder. Relying on these sensors, the engine controller can keep each cylinder's spark timing advanced right to the hairy edge of knock, providing peak efficiency on any fuel and preventing the damage that knock can do to an engine. But, noted Schiller, only a few vehicles calibrated for regular fuel can advance timing beyond their nominal ideal setting when burning premium.

For the 1400...in a word. Regular.