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Discussion Starter · #1 ·
Bike feels a little heavy, I was using 93 octane
and after reading the 87 is best, i switched down to it and
it feels my bike is a little sluggish, i checked the choke to make
sure it didnt vibrate open and everything is the same.
could it be the valves?! how do i clean it out?! thanx
 

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I tried running a tank full of 92 octaine about a month ago, hand have not gone back to the 87. I feel a difference in the way she runs and performs, and starts
 

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All I run in my 13c is the premium. More power, better mileage, smooth starts. Havn't used regular since the second tank that went through it with no problems in 9000 miles. By all means run a higher octane and enjoy all the bike has to offer.
 

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It's a common topic as to what octane you should run in your bike. Lots of people spend on the premium and swear they get better performance etc...

But from a purely mechanical standpoint running high octane in our low compression engines will actually give you lower performance numbers. The seat of the pants judgement is relative and I think usually tends to come into play in justifying the higher cost of running the top end gasoline.

High octane gas requires a higher compression rate to burn correctly. In a lower compression engine it burns a little slower causing less power as the gas in the cylinder expands at a slower rate. That means the gas expands as the piston is already on it's down stroke and you lose power.

Lower octane gas in a high compression engine burns too fast so the expansion occurs while the piston is on the upstroke. Which means the engine has to fight itself just to finish the stroke. Which is why you'll see car's that say "ONLY use 93 octane" Using a lower octane gas can cause damage to the engine.

Obviously the best ignition point is directly at the top of the stroke so as the gas expands the maximum amount of power can be applied to the down stroke. Assuming the engine is timed right, you'll get that buy running the octane that is recommended for the compression ratio your engine uses. For us that's 87 octane unless you've added high compression components to your bike.

Running high octane gas doesn't usually hurt anything but it certainly won't help either.

People got into the habit of using high octane gas in the past because the higher the octane rating the better the fuel. Lower octane gases were dirtier and had more contaminants. However, with modern fuel refining processes that's no longer the case.
 

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The bikes are built with variances in the tolerances. Plus, fuel in different areas is different. The engineers at Honda may say use 87, but as always the engineers are wrong in real life. If your bike pings or you feel the ping vibration (like mine had) step up to a higher octane. Additives, alcohol, etc., required by some state and federal laws affect what the fuel does too. My bike is almost vibrationless now.
 
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