fuel octane??

Newbies, introduce yourself here. Are you thinking about getting one and have questions? Ask your basic questions here. Please post any tech questions in "The Order of The Greasy Wrench" section.
Forum rules
Here's the place for those who are newb or thinking about buying a Ural or Dnepr to introduce themselves ask those typical "newbie" questions. Try using the "Search" link at the top of the page to see if your question may have been asked before. Please post any tech questions in "The Order of the Greasy Wrench" section.
greywolf138
New Member
New Member
Posts: 9
Joined: Thu Nov 02, 2017 2:06 pm
Contact:

fuel octane??

Postby greywolf138 » Mon Nov 13, 2017 8:25 pm

I notice that the ural engine is only 8.5:1 compression, to my knowledge, this is a lower compresion engine and should be perfectly happy on regular grade gas. My Rocket is 8.5:1 and is perfectly happy on regular. My Kawasaki Concorse was 10.5:1 and was unhappy on anything less then premium octane fuel.
Can anyone shed any light on this for me?
Primary ride, 2014 Triumph Rocket Touring
Secondary is a 2000 Triumph Adventurer 900
Soon to be 2018 Ural Gear Up
Previous ride 2009 Kawasaki Concours
past rides number about 25 from 175 two strokes to numerous 450's and 650"s

User avatar
Lokiboy
Order of Suvarov
Order of Suvarov
Posts: 2921
Joined: Fri Apr 29, 2011 9:58 pm

Re: fuel octane??

Postby Lokiboy » Mon Nov 13, 2017 8:40 pm

OMG! I’m sure others will chime in, but please, please do a search - this topic has been beaten to death. With that said, having ridden over 70,000 km I’ve never used anything but 87 octane.
2011 Gear Up - "Erika"
Yorktown, VA

Mains: 127, Idle: 40, Needle: 1 shim
MKIII air filter
70,000 km and counting

hotflash44
Hero of the Soviet Union - 2017
Hero of the Soviet Union - 2017
Posts: 2013
Joined: Mon Mar 13, 2017 7:03 pm

Re: fuel octane??

Postby hotflash44 » Mon Nov 13, 2017 9:09 pm

I personally don't care about saving a few cents, i use 91 octane in all my vehicles. im not a rich guy just jaded to saving small change. (wait maybe that's why im not rich.) :?
drive a 2016 gear up asphalt grey .Air America CIA circa 1967/8 Vung Tau Viet Nam USS Tutuila ARG-4 (AND JUST A TOUCH OF AGENT ORANGE!)

User avatar
Niteblues
Commissar
Commissar
Posts: 9752
Joined: Thu Aug 14, 2008 5:26 pm
Location: Rockmart GA

Re: fuel octane??

Postby Niteblues » Mon Nov 13, 2017 9:20 pm

what Lokiboy said...

Interestingly though, mine likes 91 the best. I have put the 87 in but it skips and burps, sometimes diesels when I shut it off; it just doesn't run right on the lower octane. For 50,000 kms worth of riding I have found this to be true.

...it's Russian. :wink:
Scott

2004 Ural Patrol

"You can ride farther in one hour than you can walk in a day"

"Media bias contributes to erosion of the perception of truth." Tanya Marcum

User avatar
BillyG
Thread Killer
Thread Killer
Posts: 2992
Joined: Wed Jul 18, 2007 2:05 pm
Location: NSB, FL
Contact:

Re: fuel octane??

Postby BillyG » Mon Nov 13, 2017 9:56 pm

Compression is just one in a long list of things that affects what octane a engine needs. Comparing a Triumph or Kawasaki engine to a air-cooled Ural engine is apples to oranges.
Bill Glaser
2002 Ural Patrol "CYKA"
300,000 km's since May 1st 2002
The "Unofficial Ural Service Manual" can be viewed at: http://www.myural.com

User avatar
Albuquralque
Hero of the Soviet Union - 2017
Hero of the Soviet Union - 2017
Posts: 18653
Joined: Thu Jul 19, 2007 2:46 pm
Location: Albuquerque, NM

Re: fuel octane??

Postby Albuquralque » Mon Nov 13, 2017 9:59 pm

Niteblues wrote:what Lokiboy said...

...it's Russian. :wink:


+1
"Put a little gravel in your travel"

Darrell - Albuquralque
2014 Patrol - Babe the Blue Ox
EFI Map OR 1.02
Throttle Body Vacuum Ports
K&N Air Filter
Raceway 2-into-1 Header (Right Side)
Previous Urals Owned: 2004 Wolf, 2006 Tourist, 2006 Patrol (TOW), 2006 Patrol (TOM)

stagewex
Hero of the Soviet Union - 2017
Hero of the Soviet Union - 2017
Posts: 4964
Joined: Sat Jul 14, 2012 10:45 pm
Location: New Rochelle, New York

Re: fuel octane??

Postby stagewex » Tue Nov 14, 2017 9:47 am

Same here, 91.
It'll run on basically anything but as mentioned sometimes diesels when shut-off using 87. Some popping too.
She knows what she wants and so do I.
Stagewex

2007 Ural Patrol, 2006 Yamaha TW200, 1995 BMW K75, 1969 BMW r60/2US

User avatar
Mr Wazzock
Hero of the Soviet Union - 2017
Hero of the Soviet Union - 2017
Posts: 1615
Joined: Wed Feb 01, 2017 8:22 pm
Location: Boston, UK
Contact:

Re: fuel octane??

Postby Mr Wazzock » Tue Nov 14, 2017 3:03 pm

You guys seem to have lower octanes than we do (UK) - our "regular" is 95 and "premium" (labelled as "super" or "ultimate") is 97 - dealer advised me to use the 97, "makes it a bit smoother and a bit more power", well possibly but is a very subtle difference.

.
Mike H
2016 Ural cT, in glorious terracotta

rivers
Hero of the Soviet Union - 2017
Hero of the Soviet Union - 2017
Posts: 8228
Joined: Sat Jul 24, 2010 10:04 pm
Location: west WA

Re: fuel octane??

Postby rivers » Tue Nov 14, 2017 4:08 pm

Mr Wazzock wrote:You guys seem to have lower octanes than we do (UK) - our "regular" is 95 and "premium" (labelled as "super" or "ultimate") is 97 - dealer advised me to use the 97, "makes it a bit smoother and a bit more power", well possibly but is a very subtle difference.

.

True. Euro 91 is the approx equvilant of US 87.
Joe
014 GU
"I'm lost but I'm making good time."

User avatar
Bilgekeeldave
Commissar
Commissar
Posts: 3449
Joined: Thu Jul 19, 2007 12:04 pm
Location: Western Washington

Re: fuel octane??

Postby Bilgekeeldave » Tue Nov 14, 2017 4:58 pm

I only use regular in my Dnepr, it also has an 8.5:1 compression ratio. I also use my Dnepr's gas tank to dispose of old gas and chain saw premix. It burns it all with out a problem.
RAMCO-Dnepr MT-16

User avatar
windmill
Order of Victory
Order of Victory
Posts: 5254
Joined: Tue Feb 12, 2008 1:17 am
Location: Kent, Wa

Re: fuel octane??

Postby windmill » Tue Nov 14, 2017 5:12 pm

stagewex wrote:Same here, 91.
It'll run on basically anything but as mentioned sometimes diesels when shut-off using 87. Some popping too.
She knows what she wants and so do I.

Same here, 100k km on my 07 Patrol, it lets me know right away is my fuel is old or low octane.
Barry

"Take care, sir," cried Sancho. "Those over there are not giants but windmills".

2007 Patrol 100k km and counting,
2018 M70

User avatar
harryball
Order of Lenin
Order of Lenin
Posts: 1065
Joined: Mon Oct 12, 2015 10:53 am
Location: Georgia
Contact:

Re: fuel octane??

Postby harryball » Tue Nov 14, 2017 6:54 pm

I have the definitive answer... What it runs best on. Octane is about more than compression and air-cooled engines can run hot.

As an experiment, I put 87 octane in my wife's rig but did not tell her. She told me something was wrong with her rig. It was popping too much and when she shut it off, it dieseled. I returned her to 91 octane and later tried the same trick with 89. She didn't complain but the rig did take up the habit of a short pop occasionally after shutdown. On 91 it never does that.

My tourist, on the other hand, will fart and pop on 87 but runs fine on 89.

However, both rigs do best on ethanol free 90.
---
2008 - Tourist - "Ursula" / 30mpg / 32k as of 9/2017
2010 - Patrol - "The Rattler" / 32 mpg / 53k as of 9/2017
K28 tires on both rigs, pusher gets about 6000 miles give or take.
3/8" toe in and 2.5 degree lean
Robert
http://HabitatForBats.org - Give a bat a home!

User avatar
:FI:Igor
Hero of the Soviet Union - 2017
Hero of the Soviet Union - 2017
Posts: 527
Joined: Wed Oct 26, 2011 7:32 pm
Location: Near Dothan, AL 36375

Re: fuel octane??

Postby :FI:Igor » Tue Nov 14, 2017 6:57 pm

Owner's manual says 91 octane, so I use 91(or better) octane.
2015 Ural Patrol (Светлана)
2006 HD Low Rider
2013 Ural Patrol 'Ursula' (2015 Totaled!)

User avatar
Lokiboy
Order of Suvarov
Order of Suvarov
Posts: 2921
Joined: Fri Apr 29, 2011 9:58 pm

Re: fuel octane??

Postby Lokiboy » Tue Nov 14, 2017 7:54 pm

harryball wrote:I have the definitive answer... What it runs best on. Octane is about more than compression and air-cooled engines can run hot.

As an experiment, I put 87 octane in my wife's rig but did not tell her. She told me something was wrong with her rig. It was popping too much and when she shut it off, it dieseled. I returned her to 91 octane and later tried the same trick with 89. She didn't complain but the rig did take up the habit of a short pop occasionally after shutdown. On 91 it never does that.

My tourist, on the other hand, will fart and pop on 87 but runs fine on 89.

However, both rigs do best on ethanol free 90.


Did you readjust your carb settings? I went the opposite - 87 normally, tried 92 octane for two tanks of gas. Initially, all sorts of problems. Reason, the carbs needed to be adjusted. Went back to 87
2011 Gear Up - "Erika"
Yorktown, VA

Mains: 127, Idle: 40, Needle: 1 shim
MKIII air filter
70,000 km and counting

User avatar
Eric N
Hero of the Soviet Union - 2017
Hero of the Soviet Union - 2017
Posts: 416
Joined: Sun Jul 24, 2016 3:26 pm
Location: Westminster, Colorado

Re: fuel octane??

Postby Eric N » Tue Nov 14, 2017 8:10 pm

Compression is just one factor, timing curve is another. A lower compression engine running advanced timing will still need higher octane gas, low octane burns too quickly. My C5 ignition seems to have a fair amount of advance, prefers higher octane than the old Type III ignition.

I think you're finding the higher octane ratings as Ural tries to get the most power out of the engine design while still passing emissions. Odds are that's a higher advance curve, leaner fuel mixture, requiring a higher octane than slightly less advance/ richer fuel mix. Not familiar with the EFI arrangement but I suspect the Offroad map will allow for lower octane with fewer problems, a tad more power and lower mileage.
2001 Patrol


Return to “Ural/Dnepr 101 - Newbie Questions”

Who is online

Users browsing this forum: Google [Bot] and 6 guests