Harleys and premium gas

[Macrider]

Yeah ,its me again talking about Harleys.
When I go out with my Harley buddies they always put premium gas in their bikes
I asked one of them once if they could run their Harley on regular gas and he said no way, Harleys are only allowed to run on top quality premium.
Why is that? Something to do with compression?
It doesn,t make sense when Harleys only have 65 H.P.
Rockets have 140 and run fine on regular.

 

[tdragger]

Yeah ,its me again talking about Harleys.
When I go out with my Harley buddies they always put premium gas in their bikes
I asked one of them once if they could run their Harley on regular gas and he said no way, Harleys are only allowed to run on top quality premium.
Why is that? Something to do with compression?
It doesn,t make sense when Harleys only have 65 H.P.
Rockets have 140 and run fine on regular.

you got it. compression and tune.

 

[TxRIIIRider]

Yes, our stock Rockets have about a 8.5 - 1 compressin ratio. About the same as a push mower.. That and liquid cooling allow us to run gas with less octane without danger of pinging. Harleys have a higher compression ratio and air cooling which is nkt as even as liquid cooling and can cause hot spots. High octane fuel resists pre-ignition better under these conditions.

 

[Huntin Dawg]

I just politely nodded when the Triumph sales guy told me to run "premium" only in the R3R. I haven't checked the operator's manual's fuel recomendation but I figured regular was a no brainer when I saw 8.7 in the specs. My Victory Vision is 9.4:1 and prefers "mid-grade" but there's no need for less explosive premium fuel at that low of a ratio. I'd be surprised if stock Harleys run over 9.5:1 and warrant the high $$ gas. Maybe those guys are just so used to paying a premium for everything associated with their bikes that they just feel the need to overpay for gas too!

 

[Pig9r]

I always thought it was because they run so hot that they needed premium which is less likely to cause detonation.

 

[TheMadScientist]

Owning a Harley is like dating a Hot Chic, High maintenance. They want the most expensive drinks(gas). They want the most expensive jewelry (accessories are over priced). They want to be center of attention ( loud pipes). They shake their ass excessively(vibrating engine). They are a trophy, all bright and shiny but no substance.
Give me the fat chic, give me the Rocket!
Everybody knows Fat Chics try harder!

 

[TOMCAT]

You can run the earlier Evolutions on 91 octane no worries .. newer Twincams will ping their heads off on anything less than 95 ... they prefer 98 octane.

 

[TRIIICK]

You can run the earlier Evolutions on 91 octane no worries .. newer Twincams will ping their heads off on anything less than 95 ... they prefer 98 octane.

At 89 Octane with 10% ethanol mine pings a little. I've been running 89 with a Seafoam additive for awhile now no pinging..?? Maybe it has something to do with keeping the injectors clean.

 

[R3Tex]

I run premium in both my Rocket and HD. The little bit of extra $ on 5 gals of gas isn't worth pissing and moaning about IMO...if it helps great, it can't hurt

 

[tdragger]

I run premium in both my Rocket and HD. The little bit of extra $ on 5 gals of gas isn't worth pissing and moaning about IMO...if it helps great, it can't hurt

You will find several threads on this board regarding running premium in your Rocket. Basically it is not advised to do so.

Unless you have some sort of internal compression mods or such, running premium in the Rocket is a negative, not a positive. It is not built to run high octance, slow burn fuel and many leave more residue in the chamber than you want to know.

Just because a Harley requires the high test stuff doesn't mean that it is a good thing for your Rocket.