Regular fuel vs Premium fuel?

[Bounce]

https://bfy.tw/K3HH

 

[Gitbox]

Philter, I don't think your rattling is due to pinging but more likely just that the revs got too low.

 

[hppants]

But I am curious (definitely NOT stressing) about Philter's condition - what exactly is that rattle he describes? We've all done that before - I've done it on many motorcycles. We don't have "hills" down here, so it usually happens for me when I'm trying to start in 2nd (or 3rd) gear instead of 1st. You'd think I'd have the common sense to glance down at the gear indicator, but I don't...

I thought it was a chain rattling (mechanical noise), but that can't be now that I think more about it.

Is that pre-ignition ping or detonation?

 

[feejerbkb]

To the O/P, the FJR engine is timed (retarded) to take advantage of the faster burning quality of regular grade gasoline. If the engine were designed to run on premium it would likely have a higher compression ratio and slightly advanced timing over what we currently have. Being that things are what they are with the FJR engine, you may actually see slightly less performance/mileage from premium because the peak combustion pressure will be less than if running regular.

Save your $ and run regular but don't buy the cheap brands. Stick with tier 1 brands (Chevron, Texaco, Shell, etc.). One of the gurus over on the cog-online forum says he can tell if somebody has been running quality gasoline or not based on what he sees when doing an engine teardown.

 

[bigjohnsd]

<blockquote class='ipsBlockquote'data-author="Pterodactyl" data-cid="1406240" data-time="1537840936"><p>

If you use premium your FJR will accelerate much quicker, add 20 MPH to its top end, handle like a MotoGP bike and get 75 miles per gallon. Your acne will also clear up and that all too often sexual impotence just may go away.</p></blockquote>

Good to know you speak from experience. I'll take your word for all but the MPG.

 

[deagle]

Original poster: Everybody says (and the manual) that regular is fine. I many times put premium in because it gives me a warm and fuzzy feeling. I also use motorcycle specific Mobil 1 and the OEM oil filter for the same reason. If I'm throwing away a little money while doing something that I really enjoy then I really don't give a sh*t. My bike is for fun time, not a commuter.

I also don't put on tens of thousands of miles annually like some do.....so your savings or spending on gas may vary.

 

[FJRPittsburgh]

Hi everyone.

Hi BlueSky!

I am a relative newbie to this forum as I am to my newly acquired 2013 Gen 3 FJR.

Excellent! Congrats!

Any opinions on the bike running regular vs premium fuel?

Yes.

Bike calls for regular.

Correct.

Will premium have better performance?

No.

Any adverse effects with premium?

No.

A waste of money?

Yes.

Comments?

Yes. Enjoy that bike, run regular unleaded gasoline, and save your money.

Welcome aboard!

Do some searches on the forum for any information you desire.

Attend as many rides as you can and meet some of these fun folks.

Don't take any of the ribbing here personally.

 

[mech 1 twa]

But I am curious (definitely NOT stressing) about Philter's condition - what exactly is that rattle he describes? We've all done that before - I've done it on many motorcycles. We don't have "hills" down here, so it usually happens for me when I'm trying to start in 2nd (or 3rd) gear instead of 1st. You'd think I'd have the common sense to glance down at the gear indicator, but I don't...
I thought it was a chain rattling (mechanical noise), but that can't be now that I think more about it.

Is that pre-ignition ping or detonation?

It's neither. It's caused by lugging the engine pistons and rods are loaded hard causing the noise. Not really a good thing. Fuel octane won't change the problem.

 

[BlueSky]

Thanks everyone for all your opinions. As a new member to the forum I find this thread quite humorous; also as a new member I now realize this subject has been beaten to death. My general thoughts now is 'regular' 87 octane is the way to go.

Thanks again!

BlueSky

 

[bigjohnsd]

You will notice increased mileage if you buy gasoline without ethanol in it, more BTU's per gallon. That said, the price difference usually makes it more economical to accept the lower mileage of the ethanol fuel, except when you are going to be storing your bike for a while.

 

[RossKean]

Summer vs winter (no ethanol) gas is a little less than 2% difference in energy density (BTU/gal). 10% ethanol has maybe 2.5-3% lower energy density than summer gas - not very different from winter formulations which contain some lighter hydrocarbons.

The energy content of regular vs premium gasoline is very small but improved thermodynamic efficiency in a higher compression engine may yield more power and/or improved fuel mileage. This is ONLY true for an engine specifically designed to operate under these conditions. The improved performance is a function of the engine design, not the fuel (it just needs the "premium" fuel to avoid detonation).

The whole point of premium is to have a fuel that resists auto-ignition in the cylinder before firing the spark. Common issue with high compression engines - more heating during the compression stroke and the more easily ignited "regular" burns too soon. There are some reports that the "flame front" travels more slowly with premium fuel and some have suggested that this may result in greater carbon formation due to unburnt fuel. I haven't seen this and I have only heard anecdotal evidence - It would surprise me if "premium" is sufficiently less flammable to leave significant residues in the cylinder or around exhaust valves... (I would appreciate an authoritative reference if someone has one.)

I fill with premium gas exactly two times per year. The last two tanks before putting the bike away for the winter. In New Brunswick, premium fuel is generally ethanol free. I would rather store the bike with fuel that is less likely to absorb water.

 

[hppants]

It's hard to imagine that the connecting rod bearings on either or both ends have enough play in them to cause that sound? I'd buy piston slap, possibly.

But it doesn't sound like a knock. It sounds like detonation....

 

[bigjohnsd]

Pants, "knock" is the sound resulting from "detonation" also known as "pre-ignition.

 

[Pterodactyl]

I thought that was a ping. Well just as long as it is not a splat or kerplunk.

 

[NBB]

Ok, if you can get non-ethanol premium then there would be a benefit if the bike were to be stored.

Just my 2cents

 

[wetwolf]

Knock and ping are the same thing, but they are both detected with a knock sensor. I think in the motorcycle industry it is mostly reffered to as ping, auto industry as knock. Both are detonation/pre ignition.

 

[Pterodactyl]

I have run premium in my FJR quite a bit. Almost all my riding is done with Spousal Unit and until recently she rode her F800GS most of the time, and that bike requires premium. In our well practiced refueling routine we share a pump. I'm just too lazy to change and use a different fuel. This past year she has been riding her R1200GS and that requires 89 octane, so guess what the FJR gets.

A common misconception is that higher octane equates to more energy in the fuel; that is not the case. Higher octane means the fuel is more resistant to ignition under high compression, which means higher compression can be used in an engine and more power can be produced. Using higher octane without the benefit of higher compression accomplishes nothing of note,

 

[hppants]

To be clear, I'm questioning the actual noise that is heard when you overload the motor at low RPM. Try to start out in 3rd gear for example. I don't think what we hear is anything that is coming from mechanical parts slamming against each other unnaturally.

I think it's pre-ignition ping, detonation, or whatever term we want to use.

But then again, I was wrong before....

 

[Pterodactyl]

The ping from pre-ignition is the sound of valves being slammed into there seats by the force of a premature explosion.... or so I think.

 

[Bounce]

My understanding is that the fuel ignites before the spark sets it off. The flame front from that slams into the flame from from the spark and can happen at points in the stroke that cause damage to the piston and associated bits.

Now lets see what the pros say.

https://www.contactmagazine.com/Issue54/EngineBasics.html