i have a 90 zx7 and i put 93 in it

 

The most you should need to run is 90, not sure exactly what your year/model requires.

 

yeah I don't have the owner's manual for it, only the service manual, but I didn't find anything about it in there

 

mine is an 07 and manual says 91!

 

When it's hot outside, you might need a little more octane.
Bikes get such good mileage. Does it really matter to save a buck on regular vs. premium?

 

I have a 2006 636 and it has a sticker right on the tank that says, warning
90+ octane only, Any use of lower octaine fuels may result in engine seizure and damage. Your bike is high proformace machine not a ninja 250 you should only be using high octaine fuels and 100% synthedic oils. Don't put cheap crap in ur bike. I always put into the highest octaine in. the most it ever cost me like $11.00 your tank only takes 4 gal of fuel

 

I'm not concerned about the cost. I bought it about a month ago and just didn't think of it until now, never had anything nice that needed btter fuel. And just changed the oil yesterday, went full synthetic.

There's about half a tank of low octane in it now. Do I have to do anything special or just let it run down then fill it with high octane?

 

Don't even think about. Just fill it up when you need to. Busier gas stations have fresher gas. notice the crown of the concrete close to the pump. sometimes it can have the bike leaning the wrong way and going downhill when you put the bike on the kickstand. having a bike roll off the stand when your back is turned can ruin your day.

 

even if there is a 50 cent differnce between them and you fill up thats a savings of only $2 at 4 gallons usually there isnt even that much of a difference so everyone can afford 90 its not much cost difference run the good stuff

 

Put whatever makes it run the best and get the best mileage. I have been running hi-test even though the manual sez regular. The same guys who tell me I'm wasting money claim non-ethanol fuel makes more power and better mileage. You can't have it both ways. The Blue Whale starts easier and gets better mileage on primo, so maybe it runs better, too. It's worth the extra pennies per gallon to me. And some name-brand premiums have the sort of additives we all like to buy by the expensive can full and brag about how well we take care of our motors and fuel systems.

 

I use the highest that Shell carries...I think it's 95 or something.

 

I'm excited to fill my tank next lol thanks guys

 

filler er up with 91 today, it was the highest the gas stations around here had.

 

WHAT?
In europe you cant find ANYTHING under 95 anywhere!!!!
I use 98 in my bike, its better for the engine.

 

I think Euro numbers are MON (motor octane number) while in the U.S. it's RON (research octane number) which shows a lower number here for the same thing.

 

It was Shells highest stuff, their V-Power or whatever

 

Some of the local Sunoco's sell the 100 octane unleaded around Tampa and St. Pete. There's supposed to be a dedicated pump for this. I think it's around 5 or 6 bucks a gallon. I haven't stopped at a sunoco station in years. I may give it a try. Seems like a waste of money unless there was a turbo installed or race compression pistons.

 

Your last sentence says it all man. Waste of money unless you have above stock cylinder pressures and pre-ignition (spark knock) is an issue.

 

have a look at this. this will help you make a descision: http://www.daytonamotorcycletraining.com/Motorcycle-Gas.htm

 

Recently I have been putting 94 octane in I really don't think the bike needs that but I just wanted to see if there was any kind of noticable difference betwee 91 and 94.. the only thing I've notice is my exhaust seems to backfire or "pop" a few times when decelerating without gear change from high rmp at low speed. for example, I'll be revving at lets say 5-8k rmp in first gear and if I just kick off the throttle she will pop quite a bit. I never noticed this on 91 oct I'm not sure what the relation is if any. If anyone has insight I'd love to hear it.

 

The higher the octane #, the slower the burn and the cooler the fire. High-compression motors need high octane to compensate for the heat created. Heat and pressure are interchangeable (basic thermodynamics) so a motor whose compression produces more heat needs slower, cooler burning fuel to keep the combustion chamber from overheating which causes detonation (premature ignition before spark). Your decel pop is likely caused from a combination of things such as a richening of the mixture as the throttles slam shut (lack of air for the air-fuel mix), valve overlap (amount of time or degrees of crank rotation when both intake and exhaust valves are open ( straight blow-through of a fresh charge) and over-advance spark timing from the sheer rpm at which the pop occurs. Big overlap is necessary to produce high rpm power and most modern high perf motors have quite a bit. The lower octane fuel probably burns a bit quicker and the pop, while still there, is a little more subdued because it occurs farther back inside the motor.

 

I noticed when riding in Montana last year that the range of available octane was lower. Normal regular here is 87 while there it was 85. Maybe less octane is required at altitude?

 

that is correct.

Wait... Wouldn't higher octane burn cleaner, there for your carb wouldn't be as dirty when it sits?

nope

Well as usual you are absolutely right RR! Low octane fuel burns much quicker, so if the engine is designed for 87 octane, you actually lose performance and mileage by using premium fuel! Premium fuel should only be used in high compression engines to prevent pre ignition!

correct again.

so i have been running 93 in my 7. but last tank i put 89 in it it seems to be doing a little smoother... does anyone know what is recommended for this bike?

ive been running 87 in my 05 for years now.

its listed in the manual.




a short read....

Octane rating

Righto, so this tends to come up a bunch (especially in the Spring-Summer when a new crop of riders come along) and I am sick of repeating myself over, and over, and over, and over, and over again. People have all sorts of ideas as to what octane rating correlates to, lots of wives tales are out there, and frankly after enough B.S. saturates the social fabric who knows what’s right and wrong anymore. Quick Summary: Octane has no correlation to power. I don’t care what your Uncle Rick or your best friend whose worked on cars since the 1930’s has told you. They’re 98.7% wrong and you’re all gullible for believing the hype.

It’s my belief that a large portion of people that are stuck on things like octane having any ties to engine power will likely cover their eyes and click wildly until the browser closes then to read what I have to say, because ignorance is bliss… If not:

Part of the problem with people’s misconception of octane rating lies with how fuels are named. The fuel companies don’t advertise “87 octane” or “92 octane”, they advertise “Regular”, “Plus” and “Supreme” gasoline. Naturally if I wanted the most out of an engine I’d lean towards something labeled “supreme” over “regular”… Talk about a scam…

So allow me to back the truck up a wee bit and explain what octane rating means. Allow me to proffer a little “concept check” if you will. There are two common ways to “test” a fuel’s octane rating. A special test engine is used which can run a variable compression ratio. The engine is then tested with isooctane (a type of additive used in gasoline) which is determined to be 100 octane. Under a variety of controlled circumstance the engine is run. Then using a grade of gasoline to be tested, its results run in the same conditions as isooctane are compared. This “percentage” of knock resistance as compared to isooctane is its “Research Octane Number” or RON…

Hold up a minute: Knock resistance? You mean power right? No I don’t. Power has no bearing to octane rating. None. Nada. Zilch. The fuel being tested is only tested to it’s resistance to knocking, or detonation. That is ALL AN OCTANE RATING IS. I’ll elaborate to where power comes into play, and why higher octane fuels are desired in a minute.

So the RON rating is used pretty extensively throughout the world. The lowest “octane rating” you’ll see in most of the world is 91 octane. Take a look under your seat where Kawasaki recommends the type of fuel to be used: Its 91 RON… So here’s a big point of confusion: In the USA the RON system is not used. Instead the AKI rating (Anti Knock Index) is used. Instead of simply using RON, the formula is (RON + MON)/2. Ie: it’s the average of the RON rating of a fuel and the MON rating. MON ratings are much lower than RON ratings as the testing is a little more “realistic”. Instead of the test engine testing the knock resistance of a fuel at 600 RPM, with MON the speed is increased to 900 RPM, with a pre-heated fuel mixture, and variable timing. Compared to isooctane fuels will most always demonstrate a lower MON rating then RON.

So perhaps a fuel is tested at a 91 RON rating and the same fuel tests at an 83 MON. In Europe that would be advertised as 91 RON. In the USA it would be sold as 87 octane (the average of RON and MON). READ THE PUMP if you think I’m pulling such ideas out of my ass.

That (R+M) is short for (RON + MON).

It has literally been right in your face forever. If you’re in Europe you’re not getting higher octane gas when you buy 98 octane, you’re getting 93 AKI rated fuel by the way. If you brag to your American buddies that you’re getting higher octane fuels, then you should feel foolish.

Righto, so with any luck that should clarify the 2 fuel ratings used around the world and should shed light onto the “91” octane required for your motorcycle is really 87 octane AKI in the US. For the performance aspect, this just never sits well with people: Use the lowest octane fuel you CAN for MAXIMUM performance. What does octane do for fuel’s performance?

Well, the higher the octane the SLOWER the fuel burns. How come high performance vehicles use slower burning fuel? Good question:

The more you compress air/fuel (high compression ratio engines, supercharged engines, turbocharged engines, etc.) the more volatile the charge becomes. When an engine reaches a certain RPM the timing is advanced so the spark fires long before the piston reaches TDC (Top Dead Center) on its compression stroke. The reason for this is it takes a moment for the chain reaction of ignition to take place. Once the charge really starts firing the piston is usually just past TDC on the downward “power” stroke. The closer you can get explosion to TDC, the more complete of a burn you’ll get and the more the power you’ll create… So if you crank up the cylinder pressure with boost or higher compression ratio, the previous ignition specs might be wrong. With the higher cylinder pressures there is a greater risk that the charge will ignite and hammer back down on the piston while it’s still trying to move upward. This is a tremendous amount of heat energy we’re talking about which has no where to go, but to transfer to the piston (bad news bears), wreaks hell on performance, and will frankly kill an engine in short order. High performance engines therefore can run lower octane fuels, but have to back the timing off a bit to prevent detonation.

So “high performance” engines run into the problem where they could back off timing, but fast burning (lower octane) fuels will burn up even faster (due to the high cylinder pressures) and you have less time to which this is happening (power loss). Higher octane fuels allow the timing to remain advanced, but they aren’t as liable to detonate when the piston is still on its upward path. So it’s actually harder to get them TO fire, but will be able to burn for longer once they do fire. It’s a fine juggling act which higher octane fuels allow the end user to walk the fine line of detonation and yet get the greatest burn and consequently maximum power.

Here’s where the concept that octane = power comes from. So high performance engines use higher octane fuel, so its GOT to be the fuel that’s the secret to the added power. Simply dumping in higher octane fuel will actually LOSE you a bit of power as the slower burning charge takes longer to get ignited and won’t burn nearly as completely on a lower performance engine. You can get a bit of power if you advance the ignition timing to allow for a more complete burn, but you still won’t get as complete of a burn with the lower cylinder pressure as you would with a lower octane fuel. Then with higher performance engines the higher octane fuel isn’t allowing an engine to make more power per se; it’s allowing the engine to run safely while making maximum power. The computers on a lot of them will retard the timing if the wrong fuel is used and so lower octane fuels in those applications will lose power (as that’s not how the engine was ideally designed to run), but they will tolerate it. So remember that: Use the lowest octane fuel as recommended. This way you can push the detonation envelope and make the most amount of power. If your engine was tuned for a higher octane rated fuel, then use that octane rated fuel as to not lose any power.

Here’s an interesting Fifth Gear segment where they tested octane boosters. This is an unbiased test and the results were uniform… Uniformly bad news for octane boosters

 

I never pay attention to the octane i just chose premo at every gas station

 

some of the stations around here don't even say the octane on them, they just say supreme and regualr and such, which pisses me off. I'll spend an extra 5 or 10 minutes driving to somewhere that says the octane before I put the stuff withput an octane number in. I'm stubborn like that I guess

 

I think the common misconception with fuels is that people see "premium" and think it means "more", "better", "higher quality", as if it's a satellite TV package with more channels. Once again, Hammer hit the nail on the head.
You're fine with what the minimum rating your manual calls for unless you've done major work to your motor and increased compression. My manual calls for a minimum of 90 or 91(forget). I have 87, 89 and 93 available. I would be fine with 89 but I have full timing advance in all gears so I just go with the 93. Depending on how long it's been sitting, it's probably not 93 anyway.

 

run what makes the bike run the best... no ping is the biggest thing to listen for... my zrx looses MAJOR power with 97 in the tank... higher octane slows burn rate which in turn kills power .. simple as that.... if your bike needs the high octane then thats what ya run....

 

if your bike needs the high octane then thats what ya run....

I think most people don't know if or why they would need it. And most probably don't. They just see "premium" and think it must be triple filtered with and extra 5% of racing "stuff" in it.

 

I love "Octane Wars" threads. Always get a good kick out of them. Seems like few are very informed of when and why higher octane is needed. To all those that know, keep spreading the word. And for those that dont listen,ill continue to laugh when yur putting 110 octane in your tank, that is unless you have a turbo setup pounding out 15 psi of boost, then im gonna envy you.!!!

 

Where do you get 110? I need some for my Norton with its high-comp motor and old-fashioned hemi combustion chambers.

 

Most dragstrips usually have it. The 1/8 mile track i used to play at with my GSXR1k sold lots of it,but not to me. There was always several guys on stock bikes waiting to get sum of the "good stuff" lol.

 

I use 93 octane Sunoco, Shell, Marathon, or BP.