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Discussion Starter #1
Just wondering what grade of gasoline you all use. I've used nothing but 87 octane {regular} and 13000 miles no problems. Anyone have any thoughts? I have buddies that swear by higher Octane.
 

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87 is what Kawasaki specifies, and 87 is what I use. Folks who insist on using higher-octane gas are not only wasting money but possibly degrading engine performance and mileage.
 

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I've been using 98 lately and my bike feels sharper. I'm not sure but I don't think we have anything lower than 95.
 

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I've been using 98 lately and my bike feels sharper. I'm not sure but I don't think we have anything lower than 95.

There are three different methods of rating octane. The method used in the US begins at 87 and goes to 94 for automotive gasoline -- in very high-altitude locations you might see 85. These numbers are 4 to 6 points lower than the same fuels rated under the systems used in most of the rest of the world.
 

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Bought my z650 brand new and I used 87octane for the first 1000km.
Then for a while the bike felt strange. It had a weird response and made a couple of pings when I eventually stalled the bike. Heard the ping three other times as the bike stalled.
I figured it was engine knock, probably from a wierd spout of the engine break-in process creating some hot spots of friction.
So I switched over to 91 octane and it was night and day. Bike felt peppier, got much better mileage than the the previous tanks fillups and never again has that sound reappeared.

Now my bike has close to 5000km and I just switched back to regular octane. One tank through and I felt little to no difference. Gonna keep at it for a while and see if something changes, but I have a feeling that what ever issue I had during the break in has worked itself through.
 

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There are three different methods of rating octane. The method used in the US begins at 87 and goes to 94 for automotive gasoline -- in very high-altitude locations you might see 85. These numbers are 4 to 6 points lower than the same fuels rated under the systems used in most of the rest of the world.
Hmmm, I'm using 95 - might switch to 98. Get the odd backfire and lurch with current fuel.....
 

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I am actually trying to run out this tank so I can return to 87. I've been using 93, and had a number of backfires (as well as stalling issues) which might be related.
 

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I certainly can't say high octane will hurt the engine, but I will say this: If I am running 87 with no problems, then switch to 93 or 94 and start having problems, the fuel sure has to be considered as a possible cause. Plenty of folks know more than me, but with things like vehicles, guns, and other complex potentially hurtful and expensive toys and tools-- I go by the manuals. It's hard to get bad results that way.
 

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Discussion Starter #13
I certainly can't say high octane will hurt the engine, but I will say this: If I am running 87 with no problems, then switch to 93 or 94 and start having problems, the fuel sure has to be considered as a possible cause. Plenty of folks know more than me, but with things like vehicles, guns, and other complex potentially hurtful and expensive toys and tools-- I go by the manuals. It's hard to get bad results that way.
With the recent posts about backfiring, I might stick with regular. I'm like you, if the manual says to use a certain thing, I stick to it, I am sure the engineers have a better idea about their design. However getting something better quality "should" not cause problems. For instance I've been using synthetic oil in all my vehicles since forever. Never had a problem and lasts longer. So I understand there could be performance gain.
 

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you're wasting your money higher than 87..unless you're not stock and have radically modified.. there is a thread somewhere here by Tremonte it was early on in this group.. smart guy.. does a lot of thorough testing
 

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Just for curiosity's sake, over the past couple of weeks I ran 2 tanks of 89 octane through my Z650, then 2 tanks of 87. I really couldn't tell any significant difference in the power delivery between the two, but gas mileage was a different story. With the 89 octane, I averaged a fraction over 55 MPG. Using the 87, the mileage was a fraction over 58 MPG. Important to note, the trips made were identical over those two weeks other than maybe a couple of around-town jaunts -- overall, a mixture of in-town and highway trips that I take on a weekly basis -- and being conscious of the fact I was trying to make a valid comparison I took care to keep my riding style consistent over the entire period. Doesn't prove anything, of course, but it surely tends to support the manual's specification of 87 octane fuel.
 

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However getting something better quality "should" not cause problems.

But you are assuming that higher-octane is better-quality fuel. It's not. It's just formulated to work better in engines of higher compression ratios. Using high octane in an engine designed to run best on fuel of a lower octane rating is sort of like feeding your dog prime steak -- he might not object to it, but it's not necessarily the best thing for him!
 

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Discussion Starter #18
But you are assuming that higher-octane is better-quality fuel. It's not. It's just formulated to work better in engines of higher compression ratios. Using high octane in an engine designed to run best on fuel of a lower octane rating is sort of like feeding your dog prime steak -- he might not object to it, but it's not necessarily the best thing for him!
Good point, noted
 
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