What gas should I use in 1985 Nighthawk 650?

3520 Views 6 Replies 4 Participants Last post by hogcowboy, Feb 3, 2019

Badmojo

Discussion Starter · Feb 3, 2019

My previous bikes all called for specific fuels in their manuals; Honda Shadow took regular, Sportster took premium. The manual I found for this bike doesn't seem to specify. I live not far from a lake, and there is a gas station not too far away where I can get ethanol free gas (I understand it is popular with boaters) but it doesn't have any octane rating on the pump that I can see. Pretty sure most 'modern' bikes are built to deal with 10% ethanol gas, but not so sure about one from 1985.

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Tobacco Road

· #2 · Feb 3, 2019

Welcome to the forum....
I've been ridding Sportsters for years and always used ethanol free 91 octane fuel. My last, and current Sportster I'm working on to get back on the road, had numerous modifications to the engine, but never did I find premium (93 octane around here) necessary. The bike always ran just great on the 91 octane.

I believe your bike should be good with 87 octane (regular around here). Should you happen to hear a little pinging, which I don't think will happen, move up a step in octane. Buying higher octane than needed does not give you more power on its own,

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SemiFast

· #3 · Feb 3, 2019

IMHO there are no lawn mowers, tractors, automobiles, weed eaters, motorcycles or any other gasoline powered machine that "likes" ethanol gas as a fuel.
Just my take on ethanol in gasoline...

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Badmojo

Discussion Starter · #4 · Feb 3, 2019

SemiFast said:
IMHO there are no lawn mowers, tractors, automobiles, weed eaters, motorcycles or any other gasoline powered machine that "likes" ethanol gas as a fuel.
Just my take on ethanol in gasoline...

I don't disagree at all, but at least modern autos and bikes were engineered knowing they would probably be using it regularly. I could be completely wrong, but I'm not sure a bike from the 80's would have?

The gas station that sells ethanol free isn't the closest; so it's a bit of a hike. Very doable, just not super convenient. Also, while the regular pumps are new and modern with credit card readers, the ethanol free pump looks like a 60's throwback. It is off to the side by itself, with just "ethanol free" on it. You have to go inside and ask them to turn on the pump, give the attendant your credit card, pump it, then go back and pay for it. Also, as I said, there is no octane rating at all, so no idea on that front.

So - yes, I can get ethanol free, but it is a bit of a pain. Is it worth the pain is my question? I just got the bike, I did put regular gas in it to drive it home, and it seems to be running just fine - so I'm more concerned with the longer term impact of 10% ethanol gas on the carbs, lines etc. that were never really designed for it. What would you do?

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SemiFast

· #5 · Feb 3, 2019

Until a local fuel station started selling ethanol free gasoline, in one of their pumps, I used what I could get for years.
Now I drive about 6 miles, passing a bunch of gas stations along the way, and pay up to $2.00 more per gallon for my bike's fuel so it can use ethanol free gasoline.
But I'm all particular... So there is that.

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Badmojo

Discussion Starter · #6 · Feb 3, 2019

SemiFast said:
But I'm all particular... So there is that.

Gotcha. I think I shall do the same. Thanks!

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hogcowboy

· #7 · Feb 3, 2019

I'm not certain but I think the lowest octane being sold today is 87 maybe 86. But give your source would be ethanal free I highly suspect you'll be fine with their regular fuel. And it will probably be 87 or 89 octane. I can't imagine yours needing more than than.

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