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Discussion Starter · #1 ·
I have an 05 FXDWG, Stage 1 with modified SEII Pro exhaust (cuuently cut down baffle diverter, new ThunderMonsters on the way). A couple of the local club guys with similar set ups claim that their bikes run just as well if not better on regular gas vs. the premium specified by The Motor Company. (Where did TMC get this 91 octane recommendation anyway? Are we expected to mix premium 93 and mid-grade 89?)

I have been running my bike on regular as well for a couple of months and everything seems to be great. Does anyone know of any long term issues to running regular vs premium in a TC88?
 

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I run 89 in the winter , and 93 in the summer , nevr had any problems running 89 except it has just a bit less spunk. It starts a bit easier in the cold with the 89
 

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2005 Road King Classic
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nidan said:
I run 89 in the winter , and 93 in the summer , nevr had any problems running 89 except it has just a bit less spunk. It starts a bit easier in the cold with the 89
I'll have to try that today. I'm about ready to leave and it is 30 degrees out right now.
 

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Total Nutcase
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Lower ocatane will probably cause some denotation, which will be picked up by the spark knock sensors. They'll retard the timing to compensate, but the bike will run ok. You'll just have less power.
 

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That, and I gotta ask myself why.
If fifty cents to a dollar more per tank is gonna kill ya', maybe Wal-Mart's house brand of oil would save a few pennies as well?
And 91 is the minimum recommended octane.
 

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i've been running 87 for 20 years no problems.the only time i run higher octain is when it's real hot out or if i'm pulling a trailer with the bike.
 

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0043--Licensed to Doof!
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You can run regular in the winter, the engine likes it. Regular burns hotter than premium so you'll get up to temp if you ride in the serious cold like some do. It WILL ping under load and over 40-45 F. so keep that in mind.
 

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Run mid grade in mine.

I have a 99 FXD Twin cam with stage 1, 42Mikuni Flatside, Screaming Eagle coil pack and pipes. In our part of the world Reg is 87, Mid is 89 and Super is 91 to 93 depending on where you buy it. I run 89 as it is about a dime a gallon cheaper and I can't tell the premium runs any better. I haven't run 87 as I am sure it will make less power and probably ping under load as well as run hotter in hot weather. The mid is a compromise between and works fine for me, no ping, still lots of juice, save a buck or so a tank and it only takes 99 more to make a hundred. I run Syn 3 in all 3 holes, though I have thought about going to Mobil 1 if I could find a local source without having to go into Dallas after it. Also not sure if I could run it in all 3 holes, but that aint no real big deal. I would say if squeezing a few more pennies out is a consideration, try a tank or 2 of regular, if it don't work, go back to the rich stuff.
 

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texastooltime said:
I have a 99 FXD Twin cam with stage 1, 42Mikuni Flatside, Screaming Eagle coil pack and pipes. In our part of the world Reg is 87, Mid is 89 and Super is 91 to 93 depending on where you buy it. I run 89 as it is about a dime a gallon cheaper and I can't tell the premium runs any better. I haven't run 87 as I am sure it will make less power and probably ping under load as well as run hotter in hot weather. The mid is a compromise between and works fine for me, no ping, still lots of juice, save a buck or so a tank and it only takes 99 more to make a hundred. I run Syn 3 in all 3 holes, though I have thought about going to Mobil 1 if I could find a local source without having to go into Dallas after it. Also not sure if I could run it in all 3 holes, but that aint no real big deal. I would say if squeezing a few more pennies out is a consideration, try a tank or 2 of regular, if it don't work, go back to the rich stuff.
say what??????????????????????????????????????????????????/
 

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I run 87 Octane with a stock TC most of the time and no detonation. I can't tell the difference between 87 and 93. It's got 10% ethanol in it anyway so it's really hard to tell what it is.
 

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newultraclassic said:
I run 87 Octane with a stock TC most of the time and no detonation. I can't tell the difference between 87 and 93. It's got 10% ethanol in it anyway so it's really hard to tell what it is.
So how about the milage? Better? Worse?
 

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texastooltime said:
I run 89 as it is about a dime a gallon cheaper
At that rate after 3 fill ups and you can buy a coke with your savings.
 

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crash1292 said:
spend 20k on a bike then run the cheepest stuff you can in it????
hey maybe it will run in fuel oil too
Hey maybe. You never know.

Wait it is called a Hog. Would pig urine work? %[email protected]
 

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Doing time, behind bars!
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Use only gasoline with the octane recommended in your owner's manual.

A common misconception is that octane measures the quality or power capabilities of gas.

But octane is simply the measurement of gasoline's resistance to detonation or pinging.

So using higher-than-recommended octane gas is a waste of money, while lower-than-recommended octane will result in poor performance and increased operating costs.
 

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@gree: I still have yet to figure out why people are so hung up on octane numbers. It doesn't burn hotter or cooler for different ratings. If you are running higher compression ratios then you need higher octane to control detonation. Your system is not going to gum up running 87 and its not going to get cleaned out with 91/93. Be smart about it, run 87 if it starts to ping put 89 in. If it pings/knocks with 89, put 91 in. I bet if you talked to a MOCO engine designer or whoever came up with the 91 min. its probably so they don't have to cover a warranty for someone that ran 87 and had detonation and broke the engine. %[email protected] :beatdh:
 

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Discussion Starter · #18 ·
Thanks for the comments. The cost of a tankful has never been the issue- I was more intrigued by the other riders comment that they believe their bikes ran better on regular after opened up to breathe better. If that was so, why put something in it that it doesn't work as well? Plus a lot of my riding heads out into very rural country where gas is hard to find and a hillbilly shack station may have regular if nothing else.

But the points made in this thread are well taken. It's not as cold down here in FEMAland as in cheese country but is has been mostly in the 40s to upper 50s since I've tried running regular. I know about the heat produced but I couldn't tell any difference in perfomrance. No pinging.

It does get Satan hot in the summer- sounds like higher octane will be better under that condition. Thanks again.
 

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Then of course there is still the issue of just what octane gas am I getting when a pump only has one hose. I think this was a thread here quite some time ago.
 

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05 Ultra said:
So how about the milage? Better? Worse?
Mileage on 87 octane is usually 42-44 mpg. Can't tell any difference. Yes, I can afford premium, too.

Correct me if I'm wrong but I've noticed that some of you folks like to follow all of the rules of the MOCO. I notice that you:

1. Always use premium fuel. After all, it's a very expensive motorcycle and an expensive motorcycle should have the "best"and most expensive fuel....and premium is "better" for your bike, isn't it?

2. Always buy all of your chrome accessories and replacement parts at your local dealer. After all, they need your support to maintain their life style. It doesn't matter that you could get them somewhere else for 20% off with no tax and maybe even free shipping. Support your local dealer. They have your best interests at heart and you want them to be there for you when you need them. After all, they could go out of business if you don't support them. I've seen lots of Harley dealers go out of business, haven't you?

3. Always have your local dealer do the service and modifications to your precious ride, even if they take five to six weeks and maybe even dent or scratch the machine and blame you for it. They wouldn't do that would they?

4. Always believe everything that the dealer or his representatives tell you, even if it flies in the face of mere logic.After all, they know best due to their many years of experience and, one thing is certain....the "care" about you personally. Don't they?

5. And, last but not least, you must never, ever do anything to your own bike since this will void your warranty immediately. And, don't forget to use only genuine HD filters, oil and wax....after all, it's an expensive bike and an expensive bike should have lots of money spent to maintain it....shouldn't it?


But I could be wrong........ :)

:sofa:
 
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