I've run 87 oct accidentally and the bike ran like crapola. I run 93oct.

 

I have a '09 Super Glide Custom. I started running with 93 octane, then went to mid grade and now for the past 5 tank fulls its been regular 87 octane.

The engine runs just as sweet as it did with 93 octane but now with regular I'm getting a few more miles per gallon. This might be due to the engine breaking in, since I'm only at 1,500 miles.

I did the oil changes myself at 1K miles and I'm using Walmart brand dino oil (20/50) in the engine & primary. Using 80/90 Walmart brand dino gear oil in transmission. The transmission shifts more smoothly now than with the HD stuff from the factory before. I did however splurge on a HD chrome oil filter for now.

If I find a screw up I'll report it. Before I get flamed by some of you amature petrol-chemical engineers. Keep in mind that I have run my former $500K twin turbo diesel motor yacht for 8 years on the above brand dino oils and when it came time to sell it. The engine survey showed less than normal wear and tear on the engines and passed with flying colors with compliments from the surveyor.

BTW those engines took 20 quarts of oil per change.

 

Just curious but aren;t you supposed to use tranny fluid in the primary?

 

No, it is a chain drive and you should use regular motor oil in it (not ATF, or heavy weight tranmission/gear differential lube in the primary.)



To the poster above...I'm sure the walmart stuff works good for ya. I run the expensive stuff in my bike and the cheap crap in my other toys (two land cruisers) and mid-grade stuff in my car. Does it make a difference? Maybe, maybe not.


I don't see how it can hurt and more power each way.

 

Super is about 20 cents more per gallon, +/-.. If you have a 5 gallon tank, it'll cost you a whopping buck a tank more. Then again...I haven't owned a bike that didn't require it anyway. I like it so much, I even put it in my diesel truck once.
BTW: Where the heck is it called "high test"? I've never heard that one before.

 

I get a kick out of all the posters who brought up the price difference as if that is the only consideration...especially those of you looking for 94+ octane if you're running anything other than a highly modified motor. If your bike runs better on the high test, then by all means use it. But it is NOT necessary for a great many of the harley motors out there...and can in some cases hurt your performance, mileage and contribute to engine buildup of carbon deposits.

The owners manual calls for 91 or higher as a cover your a$$ recommendation by the moco. With a properly tuned engine it is not necessary to run high test unless dealing with high ambient heat or seriously increased compression.

Personally, my bike runs better on mid-grade when ambient temps are below 80*...so when it's cold in the spring and fall I switch back to mid-grade. Not because I can't afford another $.50, but because the bike runs better.

Here in MN, we have all ethanol blend fuels which oxygenate [lean out] the fuel. So I've found when I have traveled south to states without mandatory ethanol blends, that my bike HATES high test...and so does my riding buddies bike who has the HTCC 10.5 compression setup. So on non-oxygenated gasoline we found much better results again on 89 octane fuels...even with temps in the 90's.

For what it's worth, my roadglide has the 98" motor with 9.8 compression, cams, SERT and the rest of the go fast goodies...so if I can run with 89 and no pinging. What makes all you with stage I modified bikes think you NEED super duper supreme?

 

SeaHag makes some good points there. I'm temted to try 89 next fill-up. Hell the other day I was out and stopped in to a station that had no super,and my guage was at less than the red line. I had to go on another 15 miles with heart pounding. I could have just settled for 10$ of 87 or 89 DOH!

does anyone know where I can get solid rocket fuel to try that out??

 

I'm sold on B&M Trick Shift. 93 on the gas.

 

I've heard the phrase coined by a few old timers so I thought it would be fun to use in this poll. Besides depending on the gas company there are a number of different terms for the high octane gas. So "High Test" would include anything higher than 89 octane.

 

93 or better.... Can't run reg. or mid grade. Wish I could get 103....