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Placebo or Real? 87 or 92 octane

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Hi guys
Lately I switched to 92 octane and my bikes 91NH runs smoother faster and seems to have more power.Noticed idle increased significantly and I adjusted back down but was puzzled why switching the octane increased the idle speed.
Anyway am I experiencing placebo effect or actually my bike runs better.I know it does but need your guys opinions

I would run some SeaFoam through the fuel system, (2 tanks of gas), using either gasoline, and then make the comparison again.

I think you got more Techron fuel system cleaner in the high octane gas and your bike had some deposits that got cleaned up.

Ride safely.

Larry Fine:
I have used Amoco (now BP) premium (93 octane here) religiously in my bikes since the beginning ('72 CL450, '73 CB750K, '82 CB750SC, and current '96 750NH).  They all seemed to run better and cleaner, idle more smoothly, and accelerate better on it than anything else.

I rode year round on the '73 for three or four years (no car) and never even pulled the spark plugs once due to running issues.  When I finally did, they were clean enough to put back in.  The lightest gray color and no deposits.  I still find the same to be true with the '96 NH today.

I always have used premium because they're air-cooled engines, which run hotter than water-cooled engines do. The owner's manual recommends 87 octane if I remember correctly, but bikes get enough fuel economy that I don't worry about the cost difference like I do in cars.

YMMV (pun intended)

Probably not the octane, but premium is sometimes different in other respects. Additives have been mentioned; another possibility is ethanol, or the absence of. Where I live some stations sell regular and mid grades cut with moonshine, and premium that's all gasoline.

Octane rating DOES have an effect on idle, anti-knock and performance. I used to have a practically unlimited source for obtaining 100 Low Lead Avgas and used to run it in the Nighthawk. Since switching back to 87 octane, the difference is quite the point where I am considering running premium in the Hawk regardless of cost.


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