The Best Fuel

[MiCarl]

Where does leave us poor first gen cousins with our 10.5:1?

 

Just like the 2nd gen, they call for 91 RON which is roughly 86 PON.

 

In other words - Regular gas.

[Holly]

Another problem with ethanol, it absorbs water very quickly and we all know water doesn't burn very well.

 

I stay away from ethanol as much as possible, but many states are requiring an ethanol blend, have to use all that ethanol the government is paying for some how.

 

Daryl

[bakerboy]

just put new pipes (altered road king) on my rstd, wondered if anyone has had any problems with heat or anything exhaust related. they sound great, but still would like input. thanks

[skydoc_17]

As a guy that works on A LOT of bikes here in South Central Pa. I love it when a rider comes into my shop with a bike running poorly because of "high test" gas usage. I sell a lot of plugs, I clean a lot of Carbs. and do a lot of maintenance on these bikes as a result of the WRONG gas being used in them. I just wanted to say "thanks" to you guys for keeping me so busy! Keep up the (not so) good work.

Earl

[StarQ]

I just did a 600 mile road trip on my 2007 RSTD, two up with 5 other bikes. Regular gas, speed limits mostly. Averaged 47 mpg.

[XV1100SE]

.... my 1100 Virago I ran 89 (mid-grade) and had a lot of 'popping' during decel, and since I switched to regular it's been great. For me, running the recommended grade works.

 

With my 99 Virago 1100 if I run the lower octane I get popping and the occassional backfire. When I can I use the 94 Octaine from Sunoco. If not available, I'll fill with premium.

[RandyR]

Do you have a speedo corrector? If not, it seems the speedo and odo are off as much as 10% too high, which means 10% less gas mileage than one would think.

 

I haven't checked my RSTD's speedo accuracy yet, but am making a mental note to myself to do that on the trip to Arkansas next month.

[Leland]

Speedometers are typically off 7% to 8%, but the odometers are pretty close. If you "Speed-O-Healer", your speedometer will read correctly, but your odometer will read low.

[johnbroughman]

I used to run high octain 91 and above all the time thinking it was better for the engine since it was cost higher, Sky Doc set me straight on that a few years back and I switched to 87 octain, it ran better, got better miliage, and actucally had more power, and I had blown a lot of money in the past years buying high octain, so why is this? The japs made this bike to run on low octain, when you burn high octain it fires slower, hench the compression stroke is already starting down before igition fires, this is simply laymens terms, but it has sure saved me a lot of money by switching to 87 octain. Plus I add a couple oz of Sea Foam in every 2nd or 3rd tankfull, keeps things clean and running smooth. Just made a round trip from Va to Persacola, Fl a week ago, 1,893 miles, running 80 and 85 MPH averaged 40.2 MPG all on 87 octain. Again thanks Sky Doc:stirthepot:

[Shamue]

Having been in the auto industry for several years and talked many times to high performance mechanics that build Nascar and Drag racing engines. I remember all of them

saying pretty much the same thing about stock engines and gas. Don't remember the technical reasons, but had to do with elevation. In a purchased vehicle the gas suggested on the sticker is for the area of elevation where purchased. And that could change if you were to purchase the same car in San Diego (sea level) or Denver CO. At sea level the same car may reguire high octane fuel when in Colorado it would require regular octane for the same performance (power). Now with the computer controls on the engine, john-q- citizen may never feel or notice the difference at elevation other than poor gas milage. Now with the carburated engine of my RSV I have traveled coast to coast and noticed a drop in power mainly in the mountains at which time I'll buy higher octane and get some of the power back. My hiway travel is 70 to 80 mph and never have a issue with regular gas of 87 octane. My weekend travel is usually in Northern New Mexico and Colorado the Colorado Rockies at 8500 ft and above at just above the posted speed. The carburated engine of the RSV has a lot to do with how the engine performs at different elevations verses the newer fuel injected bikes.

Sorry I don't remember the theroy behind the sea level and at altitude to be more specific.

 

 

 

What octane rating do you use? Does a higher rating make a difference in the performance level and maintenance of a Second Gen or late model RSTD motor?

Edited October 16, 2012 by Shamue
add

[twigg]

What octane rating do you use? Does a higher rating make a difference in the performance level and maintenance of a Second Gen or late model RSTD motor?

 

Yes, it makes a difference.

 

Using higher octane than needed will cost you more and slow you down

 

Octane ratings are confused with power because higher octanes were often specified in high power, specialist cars while the common herd drove around happily in their 87 Octane trucks.

 

But it has nothing to do with the energy content in the gas, and everything to do with the "anti-knock" additives. Gallon for gallon, 91 has less energy than 87, but can be run at higher compressions with the ignition advanced farther .... which is one of the ways those engines develop their power, and wear out faster.

 

If you tuned your 1st Gen by changing the cams, porting, increasing the compression ratio and advancing the ignition; then you would probably need a higher octane gasoline. Each gallon would have less energy, but you would use quite a bit more of it gaining acceleration in the process.

[PuttPutt]

I always run 91 or better in mine. On my bike un

der the seat there is a sticker...it says there to run no less than 91. So that is what I have been doing. As far as I know they will not allow ethenol on Military bases?...I know at Ft. Jackson they are all ethenol free pumps and I think at Ft. Sam in SanAntonio was the same.I just put on my bright green vest and fill her up.

[saddlebum]

I know there are people who will insist their experiences are different, and I have no desire to try and disabuse them of their beliefs, but the fact is many studies have shown over and over again that higher octane does NOT produce more power or better gas mileage. I won't take the time to document those studies here, but they are quite easy to find.

 

Higher octane does absolutely nothing other than allow a fuel to resist detonation in a spark-ignited engine (commonly referred to a "knocking") . It is important to use a fuel with high enough octane to prevent knocking in a specific engine, but anything above that provides NO additional value to the engine.

Goose

Also the higher the octane rating on a fuel the slower the burn rate and higher the flash point ( in effect octane is a flame retardent) this is to prevent preignition or engine knock in high compression engines. In low compression engines (leaving ethanol out of the eqaution) this actually amounts to a down grade in fuel quality as far as the engine is concerned. Ignition timing among other things also takes into account the type of fuel you burn. The higher the octane rating the more your timing should be advanced. Keep in mind, too much advance timing can create a hard starting issue.

Edited November 11, 2012 by saddlebum

[MikeWa]

That is true. Higher octane fuel burns slower, is harder to ignite, and is less explosive (ping). It only helps engines designed to run on it. Usually higher compression, advanced cam timing, advanced ignition timing etc. Since high octane fuel burns slower if the ignition does not start sooner all of the fuel in the cylinder will not be burned before the power cycle is over. Negating any advantage that might have been possible. Using high octane serves no useful purpose in the Royal Star since it's engine is not designed to take advantage of it.

 

 

Back in the 60's when I lived in Montana in the winter we would switch from premium to regular gas to help our cars start during those really cold snaps. Many lawn mowers will not even start or run with premium gas. You know the old 100+ octane stuff. Many modern cars with fuel injection use knock sensors to constantly adjust ignition timing to the fuel in the car.

 

Mike

[PuttPutt]

Ya know...I love this website. RON....MON...PON...There is some good imformation below. I gonna get home hop on my scoot and head to Ft. Jackson for some ethenol free 87!

[PuttPutt]

Ya know...I love this website. RON....MON...PON...There is some good imformation below. I gonna get home hop on my scoot and head to Ft. Jackson for some ethenol free 87!