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Discussion Starter #1
I was looking through the owner's manual a little bit after buying my bike, and noticed that it said to use Premium gas. Is this just "recommended," or does it require Premium? Also, is it because it's fuel injected or is it a compression thing? If I need Premium, it'll be like filling up a car once gas goes back up and I have to put 6 gallons in it. Thanks. Mike :mad:
 

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For the most part, octane requirements is mainly a compression thing. Your StreetGlide has a compression ratio of 9.2:1. I have 10.5:1 compression and run on premium straight out of the pump. So, every thing else being equal (riding style, correct A/F mixture etc....) no you don't need to run premium.

Another thing that can affect octane requirements is engine temperature. Idling along in a parade is gonna generate a lot of heat and make your engine more susceptable to pinging if you go too low on octane.

Also, running too lean in your A/F ratio (like stock settings) can cause pinging due to the higher temperatures caused by a lean mixture.


Have you installed a fuel management device yet (SERT etc)?
 

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I {Heart} Hookers.
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What Brian said. Run 89. See if it pings. Also, your bike might run fine on 89 during cool weather, but ping on days over 85* out...

If that's the case......run 91, 0r 92, or....until it goes away.

Compression = heat. Heat = preignition due to hot parts. Preignition causes pinging.

The lower the octane, the faster fuel burns. The higher the octane, the slower it burns, stopping preignition. Keep in mind though, that although you've stopped the pinging, you need to make sure it's doing it for reasons other then a lean condition and correct it.


+1 on the Fuel management system. Stock = lean on these things.
 

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Discussion Starter #4
Thanks a lot. No, I have not added a fuel management device. What's that? Also, my owner's manual stated that the bike takes Premium. That's why I was wondering. I was hoping I could run regular. Who needs to pay the extra coin? Thanks again. Mike
 

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I {Heart} Hookers.
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Who needs to pay the extra coin? Thanks again. Mike
You do. :thumb

Twin cammed engines run enherantly hot due to a lean-sided setting from the factory. Considering their low compression, the octane is probably to avoid pinging due to heat. Having oil misters spray the bottom/centers of the piston is a pretty good indication that they run hot.....
 

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No, I have not added a fuel management device. What's that?
Its a device that enables one to adjust the air/fuel mixture, such as the Screaming Eagle Race Tuner (SERT) among others.
 

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Nitrous Rules
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I use premium gas in both tanks.::lol8:lol8:lol8
 

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Just run premium, it is cheaper than busting your ring lands,or holing a piston just to save 20 cents a gallon. The EPA A/F ratio really cranks up the engine temp, especially on the rear cylinder. SERT is great for racing, but would hate to get caught on the street with a non compliant bike. Every state is looking for a quick legal way to get money for roadwork. 10,000 dollars a day for every day a non compliant vehicle is used on public roads. Plus prison time.
 

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Discussion Starter #11
Thanks Bill. My dealer told me there is a way to turn off the rear cylinder temporarily, but I forgot how. It's something with cranking back the throttle all the way while sitting still (in traffic for extended periods, etc.). Then when I take off, it automatically comes back on. Is this correct, or do I need to get my nose into my manual? Thanks. Mike
 

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Use your manual, you need to turn on that function (which as I recall is a pretty simple procedure - but I dont have my manual in front of me either) as it is turned off from the factory. Then after turning the function on, as you say, you roll the throttle forward to cut fuel to the rear cylinder. But it only works at idle as I recall, once you roll on the throttle it re-delivers fuel to the rear cyl.
 

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If you have a late 08 or 09 touring, I believe the rear cylinder cut off is turned on at the factory. Either way, when you have it activated here's what ya do....

While at idle, roll the throttle off/upward and hold it until you see your cruise control light blink. Green means its active, yellow means inactive. After it blinks, let loose of the throttle. You're all set. Only when your bike reaches a certain temp (220degrees??), you'll hear and feel the rear cylinder cut off. You might smell something strange but thats normal. When you roll on the throttle, the cylinder will turn on automatically.
 
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