[Howie]

07 iron barrel here at early break-in with british exhaust:  I've been using the highest octane available at good old BP.  Tail pipe is a slightly sooty, spark plug is chocolate brown. I haven't had any problems transitioning from moderately cool weather to cold, meaning no coughing or real hesitaition at the throttle.  Am I ok? H

[mrunderhill1975a]

That sounds like you have everything just right.  Keep up the good work.

[Ice]

 If you have no back fire, popping, stumbling knocking or pinking then it sounds like your tuning in the ball park as so to speak. congrats 

[pushrod]

07 iron barrel here at early break-in with british exhaust:  I've been using the highest octane available at good old BP.

What is the octane rating of the fuel? I would think if you have the stock compression you would not need high octane fuel.

[Rick O'Shea]

Roger on Pushrods thought. I thought the idea of low compression on these bikes was to allow the use of low octane fuel. Doesn't high octane burn hotter? Seems extra heat would be potentially detrimental especially during break in.

[bullethead63]

I've been burning 87 octane for the last 500 miles,in my 2002 Iron Barrel Bullet,with no ill affects...and I add 1 ounce of Marvel Mystery Oil per tankful of gas as well...if anything,I think that may LOWER the octane rating a bit...

[ace.cafe]

Roger on Pushrods thought. I thought the idea of low compression on these bikes was to allow the use of low octane fuel. Doesn't high octane burn hotter? Seems extra heat would be potentially detrimental especially during break in.

High octane burns slower to resist detonation by having octane additives in it.

I think that running higher octane than 87 can help, even in the low compression Bullet.
It probably doesn't need to be 93 octane, but 89 might be a good middle ground.
The Bullet has poor mixture atomization in the chamber, and this results in some raw fuel pooling in some areas, and other areas in the chamber are left lean because of that.
The lean areas can light-off earlier, and this uneven burn rate can cause heat build-up.
I have gotten good results using 93 octane fuel in my Bullet, even though it appears that the low compression wouldn't require it. In practice, it does seem to help.
It may vary from bike to bike, because each one is a little different.

[ScooterBob]

Good points, ACE - especially about the lazy mixture distribution in the combustion chamber. The biggest single problem that I have found with the crap they call motor fuel in THIS country is the fact that it is NOT a product of the distillation column - but rather an azeotropic mix of paint thinners, alcohols, vaguely flammable toxic waste and tars and asphalts. None of this crud will really bond together or vaporize very well in a combustion chamber that is not of truly modern design.The fuel is OK in a new modern and wonderful high-swirl, EFI motor. In the Bullet, however, you have a phenomenon call "cracking off" in the combustion chamber due to the lazy flow of the reactible gas in the chamber. The lighter aromatics will separate from the heavier tars and asphalts and actually "re-refine" from the heat in the chamber and light off spontaneously, causing detonation. This can occur with even premium fuels in our beloved Bullets. In India the 60 octane poop they run the bikes on is a "single molecule" distillate - right out of the distillation column and it will "stay together" in the combustion chamber just fine. It will also, even after after MONTHS in the crate, run the bikes just dandy. OUR pump fuel won't do that as the lighter aromatics boil off seemingly overnight, leaving sludge to foul the carbs and eat the o-rings and seals.

Long story short on all that jazz - shop around for a fuel BLEND - not necessarily the octane - that will not detonate in your bike. My experience tells me that BP fuels are EXCELLENT - especially those with "Invigorate" in them. They return higher mileage and offer the best "feel" under the throttle hand. 

[1Blackwolf1]

  Personally I agree with Scooter Bob..I run either BP or Sinclair 93 if I can find the later, I'm really a happy camper.  Citgo 93 is like ca-ca, and won't mention the swill Kwik-Trip advertises as 93.  And the occasional shot of MMM hasn't seemed to hurt anything.  Will.

[Edward]

I was very surprised to read these post. I live in the Isle of Man and the lowest I can buy is 95 octane. 97 and 98 is available freely also at the pumps.

[ace.cafe]

I was very surprised to read these post. I live in the Isle of Man and the lowest I can buy is 95 octane. 97 and 98 is available freely also at the pumps.

The highest that I've seen in the US for many years now is 93 octane, unless you go to an airport or a race track.
I'd love to be able to go to a station and fill up with 98 octane!

[Blue Ridge Wheeltor]

I was very surprised to read these post. I live in the Isle of Man and the lowest I can buy is 95 octane. 97 and 98 is available freely also at the pumps.

They measure it differently over there.

[Edward]

Hi Blueridge
I don't know how they measure it here but they put RON behind the octane number whatever that means.
Regards
Edward

[ace.cafe]

RON is "research octane number".

If a RON number is used in UK, then this method gives a higher number to a fuel rating than the other measuring methods.
A MON (motor octane number) is a method of rating the fuel that gives a much lower number, because of a much more rigourous set of tests. The MON number is usually 8-10 points lower than the RON number for the same fuel.
In the US, and some other countries, we use a PON(pump octane number) which is the average of the RON and MON numbers, and generally gives a number about 4-5 points lower than RON.
PON = (RON + MON)/2

So, a fuel that is rated 98 RON, is going to be rated about 93 or 94 PON here in the US.
This means that the 98 RON in the UK is about the same rating as the 93 PON here in the US. Maybe a touch better, perhaps.

[Howie]

Thanks so much for the feedback.  What a tremendous resource this forum is.  It's viery reassuring to have this weath of knowledge at a rookie's disposal,  Howie

[Rick O'Shea]

thanks for the info Ace & scooter Bob. Ive been running 87 without ethanol in my 04 iron barrel since new thinking the non ethanol fuel was the critical element. figured the low compression would warrent the low octane. I just got schooled on combustion chamber physics tonight though. I have access to 93 without ethanol ; maybe give that a shot? My bikes geared taller, up 1 tooth, and I recorded nearly 82 mpg on a recent 55-60 mph cruise. Seems unusually good. Maybe speedos off? Anyone else getting 80+?

[Ice]

Sounds like you have found a source of good gasoline.

 Ethanol blends and oxygenated fuels return 10% 15% less fuel economy than straight gasoline.
 I clearly remember the furor it cuased when this crap was foistered off on us.
My fleet manager at the time started eating malox like they were candy.

[sqf]

I can't get anything without a sticker on the pump reading "may contain 10% Ethanol".  Perhaps it is location (the NorthEast) but where can you find no ethanol fuel in the US?

[Blue Ridge Wheeltor]

Fortunately, in our area, just out of reach of Uncle Ernie, we have a Texaco chain that has 100% gas, no ethanol.
If you get 10% better mileage with non ethanol (I did an experiment with the Toyota and I do get 10% better) then even if you paid 10% more per gallon you are better off because you don't have that rubber damaging ethanol to deal with.
Another thing to consider is while pumps show 3 grades of gasoline, most stations have 2 grades in the tank-regular and premium. The mid grade is mixed at the pump. I used to assume it was 50/50 but have heard it is now weighted more heavily towards the regular. usually the premium carries less ethanol, or so I have been told. For less than a buck more a fillup, I would use the good stuff.

[Rick O'Shea]

Oconee County South Carolina, 93 octane non- ethanol @ $2.69/ gal.

[Blue Ridge Wheeltor]

Oconee County South Carolina, 93 octane non- ethanol @ $2.69/ gal.

South Carolina always runs 20 cents a gallon cheaper than NC. Asheville/Hendersonville is always higher than the rest of the state.

[ace.cafe]

I have an independent gas station near me that has ethanol-free gas, and I use the 93 in my Bullet.
Last time I bought it, it was about $2.69 also.

[single]

I wanna live in S.Carolina.When my mother leaves the nursing home,I'm comin'.And I may get there with nuthin' but the RE and whatever I'm wearing.Well,tools,of course.And the 70 Dodge pickup.And the 66 Fairlane my uncle bought new.Get all that in the truck and on the trailer,an' I am gone.See you then.

[1Blackwolf1]

  I personally want all Sunococ products back..98 Ethyl (rocket fuel)  CAM II racing oil.  That was good stuff.  You actually got what you paid for..heck you even got good gas with Shell 98 Ethyl then.  Will.

[Howie]

Remember Sunoco, dial your own octane? H

[1Blackwolf1]

  Yes sir..cost a lot more but you knew the difference.  Will.

[Chuck D]

Old farts gettin' all weepy and nostalgic over vintage gas. Sheesh! 

[ace.cafe]

Old farts gettin' all weepy and nostalgic over vintage gas. Sheesh!  

Some people may refer to us as "old farts", but we  prefer to think of ourselves as "vintage".
 

[ScooterBob]

Old farts gettin' all weepy and nostalgic over vintage gas. Sheesh! 

You whipper-snappers are just jealous because you've never actually seen gasoline evaporate ...... ! The old "Blue Sunoco" was the same as 100LL AvGas and would make my old Mercury Marauder FLY! .......

[Chuck D]

Some people may refer to us as "old farts", but we  prefer to think of ourselves as "vintage".
 

I'm in the old fa...er, vintage category myself. 48 this past saturday. I still sometimes say "high test" only to get a blank stare.

[1Blackwolf1]

  I say Ethyl and kids think I'm talking about my Aunty.  98 Sunoco was all my 67 LTD police car would run on.  Unless I had a few $ extra and cranked her to the sky.  No ping no pop.  Great stuff.  Will.

[ScooterBob]

  I say Ethyl and kids think I'm talking about my Aunty.  98 Sunoco was all my 67 LTD police car would run on.  Unless I had a few $ extra and cranked her to the sky.  No ping no pop.  Great stuff.  Will.

390 or 427FE? That old pig iron would RUN, wouldn't it? Heeheehee!! A Hyundai Exel with a coffee-can muffler on it just ain't the same ...... 

[1Blackwolf1]

  Only had the 390 w/monster weber carb.  Was a prior detective car.  Loved the rear heat and that the cage was still in her (as well as siren).  Could really roast off a pair of tires.  Passed anything but the gas station.  Ah what memories.

[Ice]

 My Chrysler Lazer XT Turbo,heavily modified for bracket racing ran like a scalded dog using this  http://www.elektro.com/~audi/audi/toluene.html

[1Blackwolf1]

  We used to call that making still fuel.  Guys did that in dirt track racing back in the 70-80's after you couldn't find Sunoco/Sinclair 98 octane fuels.  Another guy I know used to drop a handful of mothballs into his gas tank to raise the octane coefficient.  He overdid it one day and burned the vavlaves the mix was so strong.  Did that on his Moms Polara with a 440 police under the hood.   She was less than pleased.

[ace.cafe]

The prices of Toluene and Xylene(another booster) have risen considerably recently, and I doubt that many people will want to pay for what they cost now.
And you have to carry some with you, or if you need to fill up and don't have any with you, you're sunk.

Unless you're racing, I don't think it's worth the hassle or the cost. On a normal bike, life's much easier just filling at the pump.
You can get plenty of power from a Bullet on 93 octane pump gas.
If you plan to race, set it up for methanol, and drain and flush the fuel system after every outing right away.

[pushrod]

 I Googled "Octane" and found all kinds of things. apparently there are two ratings, one is research and the other is motor.
http://en.wikipedia.org/wiki/Octane_rating

[Cabo Cruz]

Well, brothers and sisters, it's been nothing but Amoco (BP) Ultimate, 93 octane in Perla (1), my 2004 Sixty-5, in 12K miles, as well as 1 oz. of Sta-Bil with each tankfull.  The results?  Absolutely outstanding!!!

Note 1:
500cc, K&N Pancake Filter, 34mm Mikuni carb, free flowing header and Goldie muffler

[Bullet.wagon]

 I envy you guys   to find such great gas,we only have ethanol mix and uh... exploding refineries in my area.

[Motor]

Yes, what a co-incidence.  The plant explosion on the other side of my county was........      Toluene!

Motor