Which grade of fuel to use?

W

Wrench8

New member
I know my bike has a compression ratio of 10:1, so which grade fuel is the best to use? I've used premium, as suggested by the service tech, since I bought it. Am I wasting money on premium or is it a good idea to continue using it?
 
The search feature is your friend. ;-)

http://www.motorcycle-journal.com/forum/paddock/21928-octane-requirements.html?highlight=octane
http://www.motorcycle-journal.com/f...ne-do-you-run-your-bike.html?highlight=octane
http://www.motorcycle-journal.com/f...ected-carburated-octane.html?highlight=octane
http://www.motorcycle-journal.com/forum/cruisers/12096-87-octane.html?highlight=octane
http://www.motorcycle-journal.com/f...on-about-87-octane-fuel.html?highlight=octane
http://www.motorcycle-journal.com/forum/cruisers/6796-m50-octane.html?highlight=octane
http://www.motorcycle-journal.com/forum/cruisers/6686-octane.html?highlight=octane
http://www.motorcycle-journal.com/f...y-faqs/6510-octane-fuel.html?highlight=octane
and so on...

The general consensus is that you're wasting money on any fuel that isn't required to prevent knock. Chances are, your bike won't knock with 87.
 
I checked my owners manual, it said 87 is recommended. I filled her up with a tank of reg unleaded and, along with fresh oil and filter, shes purring like a kitten. I experienced no knock or hesitation.:D
 
I've been using 87 regular unleaded in my 07 C90 and used the same in my 06 C50 both run perfectly on it... I also never run anything but Chevron... best gas by far in my (and many others) opinion.... :bluethum:
 
I asked my dealer this question. He said that 87 is fine. Bike motors don't get hot enough to efficiently burn premium. Use premium only if you want to clean out the carbs or fi.
 
Can anyone confirm how much fuel is in the hose on the selectable pumps ? I am thinking there has to be at least a gallon or so. I always thought at least a portion of your fill up would be the grade the previous person purchased. I could be wrong, but I am not sure how else it would work.
 
i would think that there isn't any left. i'd think that the pump pulls the rest of the fuel back into the holding tank, like a purge. probably for safety.
 
Yea, that probably accounts for the WHOOSH you hear when you shut the nozzle off and when you start the next fill-up!!! :lol4:
 
I did notice a considerable amount of black build up on the rear hub on both sides just after the exhaust pipes. So I guess the 87 octane doesn't burn quite as clean. Which makes me wonder, if theres build up outside, is there build up inside as well?
 
I use 93 when I got the extra money. I get lower MPG with lower octane gas. You may want to read up on OCTANE, what it actually does, it will surprise you.
I am using 91 right now, seems to be the happy medium for me.

And, motorcycle engines run hotter than car engines, they DO get hot enough to burn higher octane, and higher octane causes motors to run hotter.
 
If I understand it properly, higher octane fuel combusts easier than lower octane fuel, so his reasoning is flawed. Also, most regular unleaded fuel has additives to clean carbs, valves, and injectors anyway, so premium on our bikes is unnecessary.

I know for sure that Chevron, Texaco, and Marathon fuel have cleaing agents in their regular unleaded. Some companies, I believe, only mention cleaners in their premium fuels to encourage consumers to buy fuel with a higher profit margin.

If you are concerned about it, you could buy regular unleaded and run a bottle of STP Gas Treatment every now and again. STP will remove water in fuel lines, so I feel it is beneficial.

I can tell no difference in performance or mileage on my 2006 C50 between any grade of fuel.
 
Changing my blinker fluid to a synthetic gave me way more power than switching octanes, and I think my pipes are cleaner too. :whistle:
 
I'm not sure which part of his reasoning you question (several possibilities :mrgreen:) but you have the octane thing backwards. A very low octane fuel "flashes" like an explosive. As octane goes up, it burns slower and more evenly.



Your experience is typical if one is driving a vehicle (ANY vehicle) designed to use "regular" grade gas. Not everybody, mind you, but most folks would notice the same thing. Thus for most people, using a higher octane than required is just plain and simply a waste of money.

And I think the temperature difference with high octane fuel is because of engine design and not the fuel. That is, a high compression engine that requires high octane fuel runs a tad bit hotter than a low compression engine of similar size.
 
Honest to God, I'm going to loose it. Easy Rider is right about octane burn.

Just use what your owners manual says. If it says 87, use 87. Want a useless treat, add 89.

On a bike, for added wonder, think how much gas from the previous customer, is left in the hose, pump and lines. By the time you fill your tank, the gas you paid for is just barely getting to the nozzle.
 
Like everyone else says, use what the manual says. It all has to do with engine design and higher octane is mainly required as compression goes up. Higher compression causes hotter temperatures inside the combustion chamber which causes low octane fuels to explode. This is caused pre-ignition or ping. Higher octane acts as a stabilizer or retardant if you will allowing the fuel/air mixture to compress and get hotter without igniting. I know it's a rudimentary explanation but the gist of it all is higher octane has no benefits in an engine not designed to use high octane fuel. Any perceived so called improvements are seat of the pants type deals and may have more to do with brand of gas than octane. That's my 2 cents. :cool:
 
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