I've been using Marvel Mystery Oil as an addative for awhile, for lubrication of the fuel system, not as an octane booster.

Awhile back I had to take the carb off my Sportster to replace the intake manifold gaskets and it looked brand new on the inside.

It might not be doing a lot to help but it ain't hurting.




.

 

Snake oil. Don't waste your money.

 

Additives and Scents

Fuel Fragrances by Manhattan Oil
POWER PLUS CHERRY BOMB Fuel Fragrance is a unique product that is not only a proven crowd pleaser but a much needed item for many drivers that have a difficult time dealing with the nauseous odors of an alcohol fueled vehicle. Drivers that use POWER PLUS enjoy not only the pleasant fragrance but less irritation to eyes and nose and much more livable cockpit. POWER PLUS is the first of its kind creating a new category in fuel additives.

Delight the crowd with a pleasant smell.

http://www.palmerracingfuels.com/additives.htm

 

Use a "TOP TIER" gas like Chevron and you don't have to worry about additives. They blend it in.

 

Drop for drop, gasoline containing ethanol has less British Thermal Units than non ethanol gasoline. So, it takes more fuel to generate the same power, all things being equal. In most states ethanol gasoline has pretty much replaced non ethanol gasoline, so you don't have a choice. I don't worry about it any more. I have 81,000 miles on mine without any obvious problems. I buy the lowest grade my engine can burn without it having any pinging etc. Since octane just slows down the flame rate without adding any BTUs, I figure there is no need in paying for expensive octane additives unless my engine demands them. This touring bike likes 87 octane w/ethanol just fine, even in near 100 temps. It is what it is.

 

most fuel system additives are just lacquer thinner. it's about $16 a gallon at Lowe's or Walmart.

 

Interesting stuff guys, It is weird that the owner manual says not to use additives of a ny kind but harley themselves have two different kinds the winter blend and the additive? I don't know about the winter blend but I ran the bike back when it was bellow 20 and it ran just fine. A friend and I were talking about that scented stuff a few days ago thought it might be fun to play around with but not sure what it would do the engine lol.

I always use Union 76 gasoline and go for the 92 octane but i've seen many guys with twin cam harleys use regular 87 gas with no obvious issues. I just use what the manual says to use.

Any of you guys ever use lucas fuel injector cleaner in your cars or trucks? this stuff is amazing my truck was running really tired and having a hard time reving past 3500 rpm's after 4 oz's of this stuff by truck pulls clean all the way up to the 5700 rpm range. I don't know how it work but it really does, I've used the techron additive, shell vpower injector cleaner, gumout, stp, oriley FIC an all the others but the only one that I could notice any difference in was the Lucas. worth a try guys if you have a EFI bike give it a shot I think you'll be suprised how well it works.

 

This subject comes up many times on this forum. Those that state this falsehood do not realize that modern engine computer management will retard the spark to the point necessary to prevent detonation when using lower octane gas. It may be true that an engine is not "pinging," but that is because the spark is being retarded to prevent it, but there is a limit to how far it will retard the spark. This uses up the "safety value" of the management system, so when you get into a situation that creates severe knock, such as going up hill under load, or a high heat situation, you may not have any more spark retardation available. The engine management relies upon input from various sensors to optimize spark timing and engine performance under virtually any combination of load and engine speed. It determines the engine's spark-knock threshold and then retards timing just enough to prevent knock and detonation, protecting the engine while optimizing performance based on the gas being used. But it can retard the spark only so far...past that and it's going to knock.

An engine that is running with retarded spark is not running efficiently. It is generating less power per stroke.

Those of us who run older, high performance, non-computer controlled machines, know too well the problems of not having high enough octane. My '75 Triumph t150, timed properly, requires 97 octane gas, still available as aviation fuel, but illegal to pump directly into anything except an airplane. I've had to manually retard the spark settings from 38 degrees advanced, and add a double thickness head gasket to lower the compression, to even think about driving it on available 93 octane.

All modern Harleys specify 91 octane. The high heat generated by these air cooled, EPA engines is probably the number one reason. To be able to run lower octane (i.e., "cheaper") gas would be a selling point, but Harley states 91 octane.

For those who think I'm just blowing smoke, do a little research. I spent several years of my life working for the company that made the knock sensors for Chrysler and Volvo, when computer management first became available in the auto industy. Severe detonation can destroy an engine in a very short time.

Here is a very good article on this subject:

http://www.americanrider.com/output.cfm?id=1021915

 

Just started reading my new '08 manual for Softails and on the fuel section it states, "Do not use race gas or octane boosters. Use of these fuels will damage the fuel system." I was in Indiana for the latest Indy 500 and while riding my brother inlaws 'guest bike', a '97 Softail standard, screaming little beast, I went to fill up the tank and they have 93 Octane. Here in New Mexico we only have 91 as highest. What's with that?

 

And, an article on DurAlt, who makes the Harley fuel additive.

http://ezinearticles.com/?DurAlt-Fue...view&id=479245