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What grade of gasoline do you use in your C50/M50?

I've been having a problem where the engine will stall for no apparent reason. The dealer said I should be using 93 octane gas. The first tank I put in was 87 octane regular.

I'm going to switch as he suggested but I was curious about what grade gas everyone runs.
 

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on the bike itself, it should say what the minimum octane is for your machine... i can't imagine a cruiser demanding high octane fuel..
 

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I tried high octane and mine runs better on 87. If its stalling for no reason I'd have to believe there is some other problem that needs looked at.
 

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All 3 times it's stalled has been after it's well warmed up after a 10-15 minute ride. I pull into the parking space and then it just stalls before I can even shut it off.

Very weird.

I'm going to try the 93 gas and see if it helps. There's so many opinions here I think I'm just gonna have to experiment for myself.
 

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My book recomends octane of 91 or higher. But I have run a lower octane with no ill effects during use, but I believe that computer controlled ignition and fuel injection systems will compensate and give reasonably smooth running, but damage may result in the long term. I have been told that some fuels here are too quote "too oily or thick" and tend to foul plugs and dirty injectors when Suzuki's are run only on that brand of fuel. ( I have used this fuel on occasions with no effects). Friend I ride with sometimes has a GSX R 100 and my M50 and I have to work to keep up :D . Just over 7,000 miles and running well.

Hope this helps in some way
 

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I run high octane till the motor brakes in. Once that happens, I will go with the recommended octane. I notice less valve noise with the higher octane right now.

Higher octane ratings correlate to higher activation energies. Activation energy is the amount of energy necessary to start a chemical reaction. Since higher octane fuels have higher activation energies, it is less likely that a given compression will cause knocking. (Note that it is the absolute pressure (compression) in the combustion chamber which is important - not the compression ratio. The compression ratio only governs the maximum compression that can be achieved). Octane does not produce more horsepower, Octane rating has no direct impact on the deflagration (burn) of the air/fuel mixture in the combustion chamber.

Octane ratings are also different in higher altitude states: In the Rocky Mountain (high altitude) states, 85 octane is the minimum octane and 91 is the maximum octane available in fuel. The reason for this is that in higher-altitude areas, a typical combustion engine draws in less air per cycle due to the reduced density of the atmosphere. This directly translates to reduced absolute compression in the cylinder, therefore deterring knock.

Octane determination in Piston Engines
 

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I've been having a problem where the engine will stall for no apparent reason. The dealer said I should be using 93 octane gas.
:leg2: Where DO all of these incompetent dealers come from??

Exactly who at the dealership did you talk to?
If it was not the service MANAGER, go back.
If it WAS the service manager, find a different dealer.

If there is only one dealership in town AND it was the serv. mgr. you talked to, then put in a tank of premium gas and make an appointment for about a week out to take it in when it still stalls.

P.S. Do you have an idle speed adjustment? All carb'ed bikes do and even some FI models. It might be that your idle speed is just a tad low.
 

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Directly from the Owner's Manuel on an M50 (same engine).

Your motorcycle requires regular unleaded gasoline with a minimum octane rating of 87 blah, blah, blah.

The fuel is not the issue.
 

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i use i think 92 (whatever super unleaded is these days).. minimum is 91 which is listed on my bike.
Yours also has a different/higher compression.


For the M it's 87. Can't imagine how a higher octane (slower to ignite) fuel is going to help stalling issues :roll:
 

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yeah... i should have listed that... i'm still not too good at writing legit replies yet.. But yeah my sport bike requires higher octane but my dad's cruiser only needs 87.
 

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Have tried both in mine and have found that I get no difference with the higher octane than the lower. So I use the lower octane, to save money. By the way my book also says 87 minimum.
 

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Book does says minimum 87 but is it actualy THE BEST or RECOMENDED?

Someone told me that higher graded gas = clean injection system.
 

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Someone told me that higher graded gas = clean injection system.
"Somebody told me..." that's almost as good as "I heard.....". :mrgreen:

It's total BS. :shock:

Now.....higher QUALITY gas with more cleaner additives, regardless of the "grade", would be better. Good luck figuring out which brand that might be!! :roll:
 
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