Is Premium Gas Worth The Extra $? - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Carbs and Fuel System
From the gas tank to the carbs
All fuel system discussion

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 21 (permalink) Old 04-29-2012, 08:34 PM Thread Starter
Junior Member
 
Join Date: Apr 2012
Location: Lancaster County, PA
Posts: 2
iTrader: (0)
 
Is Premium Gas Worth The Extra $?

The riders I've talked to are split on the issue of regular vs. premium gas, so I thought I'd ask Vulcan riders: Is it a waste of money to run higher octane gas in your bike? I've gotten everything from "you're crazy to run regular" to "I've always run regular and never had a problem," so I'd love to hear what Vulcan riders have learned. Thanks!!
Pastorkent is offline  
Sponsored Links
Advertisement
 
post #2 of 21 (permalink) Old 04-29-2012, 08:48 PM
Prowling Tiger
 
blazblu82's Avatar
 
Join Date: Apr 2012
Posts: 2,048
iTrader: (4)
 
Dude, stick to regular. It is what the bike is rated for. Usually higher octanes are needed if an engine has knock issues OR the vehicle is designed to use higher octane fuels. Save the money and stick to regular.

I only understand what I don't understand.
blazblu82 is offline  
post #3 of 21 (permalink) Old 04-29-2012, 09:57 PM
Old Fart
 
Knifemaker's Avatar
 
Join Date: Jun 2004
Location: Catawissa, MO
Posts: 11,602
iTrader: (4)
     
Garage
The only reason to run higher octane gas is because you HAVE to....

Got a 13.2:1 compression ratio? Premiums
likely the way to go. If your motor is not knocking/pinging or burning off your spark plugs tips, you are definitely wasting your money burning high octane fuel,and may even be damaging your motor.

Contrary to what many think, high octane does not mean higher power. In a motor that runs fine on regular gas, higher octane actually puts out less power.

Save your money.

If You Are Not Sure If I Am Joking or Not....I AM !!Photos:
http://www.flickr.com/photos/knifemaker1954/sets/
Knifemaker is offline  
 
post #4 of 21 (permalink) Old 05-02-2012, 07:04 PM
Member
 
RxRC's Avatar
 
Join Date: Mar 2010
Posts: 38
iTrader: (0)
 
Quote:
Originally Posted by Knifemaker View Post
In a motor that runs fine on regular gas, higher octane actually puts out less power.
True.

"Giving the Ralph to the prairie scrub of Grand Forks is like dressing up drunken monkeys in snowmobile jackets and packing them into the Ordway....."
RxRC is offline  
post #5 of 21 (permalink) Old 05-02-2012, 07:31 PM
2000 VN 750 Senior Member
 
Join Date: Sep 2010
Location: Central New Jersey
Posts: 2,484
iTrader: (10)
   
The motor was originally engineered to run on regular. Unless you did major changes to the engine you really need to stay with regular. Why were you interested in switching? If others want to pay a higher price for fuel when it is not needed then that is their choice. Do the right thing and feed your bike what it requires.

and always remember, "Ride until you rot!"
**Really not sure if the Big "C" is back right now
but having to face the fact that this is a lifetime routine
going forward. Five operations done and it still continues.

Tom
Vulcan 2000
New ride: 2009 Victory Vision Arlen Ness Signature Series
4507 miles
Vulcan2000 is offline  
post #6 of 21 (permalink) Old 05-02-2012, 09:55 PM
Senior Member
 
Join Date: Aug 2010
Location: Daleville, Alabama
Posts: 445
iTrader: (0)
 
No. +100 to all the above. But do run a bit of Seafoam in her every now and then.

MCCT Mod
Pickup Mod
12 Volt Receptacle Mod
Memphis Shades Santa Cruz
Homemade Luggage Rack
NGK Iridium IX Spark Plugs
Harley Sportster Exhausts
Rotating/Flashing Tail Lights
170/80 Michelin Commander II
Saddlemen Highwayman Slant Jumbo Saddlebags
Bought 09/10 12.2k miles - 04/12 33.4k miles
CW-4 is offline  
post #7 of 21 (permalink) Old 05-02-2012, 11:00 PM
If only it had 6th gear..
 
DavesVulster's Avatar
 
Join Date: Jul 2011
Location: North of Boston
Posts: 1,100
iTrader: (1)
 
Quote:
Originally Posted by CW-4 View Post
No. +100 to all the above. But do run a bit of Seafoam in her every now and then.
Yup Seafoam. Not just for marine use. Good stuff.

Dave

Mods:
Jetted, shaved & coastered
Home made under-tank single filter
Converted ACCT's to manual (thanks wib714)
Dual vac lines on petcock (my cure for ticking)
LED tail/plate lights
Relocated helmet lock to license plate

Added stuff:
Customized hard bags w/ lights
Chrome levers
Hellcat windscreen
LED running lights
Home made 'Vita-Volt' meter
Foot rests on engine guard
Tunes

Hmm....she was on the back when we left.... ??
DavesVulster is offline  
post #8 of 21 (permalink) Old 05-03-2012, 01:14 PM Thread Starter
Junior Member
 
Join Date: Apr 2012
Location: Lancaster County, PA
Posts: 2
iTrader: (0)
 
Thanks!

Thank you for the good advice!
Pastorkent is offline  
post #9 of 21 (permalink) Old 05-03-2012, 05:05 PM
Crap, I WAS in 5th gear.
 
Join Date: Sep 2011
Location: So. Cal
Posts: 500
iTrader: (1)
 
Not mentioned in this thread yet: higher octane fuel can cause hard starting.

Two reasons for power loss are that higher octane fuels have less energy, and the engine is timed for regular.
Kelly2001 is offline  
post #10 of 21 (permalink) Old 05-03-2012, 06:53 PM
Linkmeister Supreme
 
OlHossCanada's Avatar
 
Join Date: Aug 2008
Location: Lethbridge, Alberta, Canada
Posts: 7,960
iTrader: (8)
   
Quote:
Originally Posted by Kelly2001 View Post
Not mentioned in this thread yet: higher octane fuel can cause hard starting.

Two reasons for power loss are that higher octane fuels have less energy, and the engine is timed for regular.
I don`t know if higher octane gas has less energy, but it is harder to ignite. That is why it is used in high compession engines, to prevent pre-ignition or "engine knock" before the spark plug fires.

The vn750 engine`s compession ratio is 10.3:1. From my experience with small block Chevys over 35 or 40 years, I would have thought that was high enough to use higher octane fuel too, until I read in the service manual and on this board that regular 87 octane is all this engine requires.

My friend has a 2005 Harley Electro-Glide whose engine is lower compression, about 9.5:1, IIRC. The H-D Motor Company recommends high octane fuel for that engine, and my friend says it does run better and has more power with it than on regular when he can`t find the high octane juice.

The only explanation I can think of is that the Vulcan may have a higher connecting rod to stroke length ratio. There was an article in an old hot rod magazine about 15 or 20 years ago that was called "The 350 that Chevy Should Have Built". To make a long story short, a stock 350 ci has connecting rods 5.7" long and a stroke of 3.48". The engine these guys built had connecting rods ~6.2" long and a 327 crankshaft with a stroke of 3.25". The longer con rod/stroke ratio means the connection at the piston wrist pin has narrower angle of movement during rotation of the crankshaft. This leads to the piston sitting at TDC (top dead center) for a fraction of a second longer on each stroke. I do not remember the whole explanation of why this allows a engine with a compression ratio in excess of 10:1 to run on 87 octane, but it does. This engine was making about 200 ft lb of torque at 2500 rpm and 400 ft lb at ~5600 rpm. Nothing to sneeze at, all things considered.

So as I said before, maybe the rod length/stroke ratio may be why the vn engine runs so well on regular gas.

Gordon

1991 VN 750 -"Cosmic Lady" or "Bad Girl"?
Purchased May 16, 2008
Approx.19,300km (12,000 miles)

H-D windshield
Relocated R/R
MF-AGM battery
Fiamm Freeway Blaster horns
F&S luggage rack and engine guard
Kury Offset Hiway pegs
July 13, 2016, Riding on the DARKSIDE now, Classic Radial 165/80-15


TOP TEN THINGS A NEW RIDER/OWNER SHOULD DO. Click on link.
https://www.vn750.com/forum/11-vn750-general-discussion/9127-top-ten-items-you-would-suggest-new-owner-do-his-new-ride.html
OlHossCanada is offline  
Sponsored Links
Advertisement
 
Reply

Bookmarks

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

Once registered, your User Name"cannot be changed". We can make exceptions within 7 days, but after that, it is set in stone.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome