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Discussion Starter #1
Having owned a Vulcan 900 for 10 years I've been involved in more tha a few discussions about octane. That bike called for 87 octane (USA Regular) and loads of owners wanted to burn 90+ because "motorcycles need premium gas". All of the research I've done indicates that you need to raise the octane once you hit around 11:1 compression. Since the 900 only developes 9.5:1, 87 octane works best. So my question is why does Kawi call out 90 octane for the 1700? I was surprised to see it also has a compression ratio of 9.5:1. Obviously I'm missing something.
 

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In germany the actual lowest gasoline is 95 octane with up 5% Ethanol (or the same called E10 with up to 10% Ethanol - never used it in any of my vehicles) , so I never thought about filling up with something more expensive.


Cu,
Sven
 

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1700's require premium, or they can ping. Even more likely after your ECU is Ivanized.
 

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I ran 87 in my 900, but when I got my Voyager I saw in the manual where it said minimum 90, so I started using 93. I run 87 in my truck so a couple times I've accidentally put 87 in my bike. I can tell the difference when I do that, too. It pings and doesn't seem to have the usual power.
 

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My 750 runs on 87 just fine. I've put mid-range gas in it only once because the mom-n-pop gas station I stopped at while on a run long ago had apparently run out of its' 87.

The bike ran fine but I did notice a decided difference in how much my wallet weighed. :(

I haven't run premium in anything since the time I owned my Mustang.
 

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The octane rating is all about keeping your engine from developing a ping.
The higher the octane number the more resistant it is to ping.
The engine makers determine the best number to use.

That's it.
It doesn't do anything else.
Some would want to believe it makes the mpg's go up, it can't!
 

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from what I found SteveJB you are correct .Higher octane is needed for Higher compression ratios. For the most part there is no need to cool things down with a higher octane well at least when I grew up. Now however with the engines being leaned out so much and the timing being so advanced to get past the EPA some engines are calling for a higher octane than I would think is needed. They have the engineers so I follow the owners manual ( sometimes) Ride Safe
 

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My 1500 calls for 91 but it pings like shit on that and I have to run 94 - it'll ping on that too on hot days. Pisses me off that it won't run properly on 91. Took it back to Kawasaki many times to get them to fix but they always claimed there was nothing wrong (pretty sure that the standard Kawasaki warranty answer for every customer that comes through the door with a complaint).
 

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Yeah my 04 1500 Nomad wanted to ping with any acceleration. I put iridium plugs in and can run mid-grade fuel in the spring and fall. switch back to premium at the first ping though.
 

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Discussion Starter #11
from what I found SteveJB you are correct .Higher octane is needed for Higher compression ratios. For the most part there is no need to cool things down with a higher octane well at least when I grew up. Now however with the engines being leaned out so much and the timing being so advanced to get past the EPA some engines are calling for a higher octane than I would think is needed. They have the engineers so I follow the owners manual ( sometimes) Ride Safe
I do follow the recommendations, but when I saw the engine specs I was surprised at the compression ratio. So I got curious. Thanks
 

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I run 93 in all my scoots, and lawnmowers...... Always have. My Voyager does not like 87 with the sugar in it at all.
 
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