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Discussion Starter #1
This may just be all in my head, but I just filled up with regular and now sometimes when I roll on the throttle hard I think I can hear and kind a gravely sound, like someone pouring gravel into a metal pan. Is that preignition? My manual says to use 86, so if it is my timing must be messed up. Thanks!
 

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What kind of bike is it??

How many miles do you have on it and have you run 86/87 before without problems?

What RPM and throttle setting were you at?

What brand of 86 were you using?



Need more info but that sounds like it may have been detonating, unlikely that you were having preignition though.


Grant
 

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Discussion Starter #7
apexismaximus said:
What kind of bike is it??

How many miles do you have on it and have you run 86/87 before without problems?

What RPM and throttle setting were you at?

What brand of 86 were you using?



Need more info but that sounds like it may have been detonating, unlikely that you were having preignition though.


Grant
700 miles and this is my second tank (just bought the bike). My first tank was 92.

I think I was at 3 to 4 grand, throttle about half, using 76-brand 87 octane.
 

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What kind of bike?


76 should have good gas, sometimes you have to wonder about the no-name stations???????



If it goes away with higher octane, then detonation is a real possibility. If you haven't burned off enough to refill with higher octane then you could try a VERY small amount of octane boost from a auto parts store. Just use a touch because that stuff can do damage to gaskets and rubber fuel line components. You're only looking to boost the octane of at most 5 gallons and only boosting it by 2-4 points.


If it keeps doing it a jet kit or power commander may help as lean mixtures detonate more easily. Have your dealer look at it too. It's got to still be under warantee so why take the responsibility of diagnosing the problem if there is one.

Re-fill with mid-grade or better and let us know what it does for the bike.
 

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Discussion Starter #9
Hey, thanks for all the help. It's an '03 Honda 919. I'll see if it's still under warranty (possible) and post back here if I figure anything out.
 

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torok: What does it say on the Owners Manual. I use regular non-leaded petrol of 97 octaine on my '97 Yamaha YZF600r & '00 Honda 929 with no pre-ignition.

Have tried up to 91 (only do a few rare stations ever have 92 or 93 so even tried that) & cannot see any difference in power to the bike, heating, fuel milage, etc. My Owners Manual, of both bikes, says 86 octane or up.

Basically since '46 all I have ever used was pump fuel, bar times I was experimenting. Just one thing I do is buy from stations I know to have fresh or good underground tanks. To often the older & especially the slightely lower priced to discount stations have tanks that are leaking out gas & taking in undergound liquids not to mention how some will illegally pump in diesel fuel to regular or high octane tanks. I have no idea how they do this, but some have been cought when the fuel was tested. Have some of that crap in your engine & it will suffer.

One can always spot a good station by the appearance of the station building being only a few yrs old, the newer pumps & that the surface has been done over again.
 

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A 919 SHOULD be able to run on damn near anything so it's timing is either wayyyy fooked up or that was some seriously crappy gas.

I say this since the 919 isn't exactly the most high strung bike out there. Moderate compression and not very wide bore vs stroke??? Likelyhood of detonation is low unless something is wrong with the bike or gas. 86/87 should work fine.
 

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Discussion Starter #12
Well, here's what I am thinking now. When I had the problem I was accelerating up hill, two up, in 90-degree weather. When you consult the manual on the subject it says that pre-ignition in this situation is normal and not to worry about it. Maybe if you are picky like me and think that ANY pre-ignition is a bad thing, you just have to use higher octane then recomended.
 

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You are simply way to picky & expecting everything to work as you so feel it should.

Also I apologize for my error of saying 97 octaine when it should be 87 octane.

I came in from a nice 8.5 run in the mtn roads on my 929 using 87 octane & this more touchy engine simply thrives on said fuel be I at low revs of 2.5 thou or up to 8 or 9 thou. To even putting a load on the motor at 4 grand to hike it up to 7 grand in 4th or taller cogs at temp of around 80 to 95F.

Possilby you are expecting to much out of your bike while it is being broken in what with two of you on it & giving it 'ell up a hill. What gear were you in when acceleration up the hill for that could have been a heavy load on a new engine if in a taller gear for this is when I would have been down a number of cogs though my ignorance as to what it is like to carry a pillion passenger as I have not done that since way back in early 50s.

Just my thoughts though feel I am close to being correct
 

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Discussion Starter #14
Yea, I may be expecting too much, but if I have to pay a dime more per gallon just for peace of mind, I'll do it.

And I never lag an engine. I don't remember exactly what gear I was in or my speed, but I know that I am always very concious of that.
 

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One more time, pre-ignition and detonation are NOT the same thing. Stop calling this pre-ignition. Or hope to god it isn't pre-ignition because it's 100 times worse than detonation for reasons I'm not going into today.


Stop lugging the engine too, it isn't good for it. Use higher revs esp in such demanding conditions.
 

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The dime more will simply go into the pockets of smiling rich refinery people.

The gear box is so you can shift down gears when needed. One does not ride a bike in its top gears till the engine stalls you know---one shifts much sooner to stay in the revs the bike appreciates.
 

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Discussion Starter #20
Well, I'm just trying to do what this manual says and what people tell me. Acording to the manual I'm supposed to be in 5th gear at 31mph, so I figure if I'm doing 35 up a hill in 4th I'm okay since the manual recomends I should be nearly in 6th if not for the hill. Of course, you guys will all tell me I'm lagging at that point, so I just don't know what to do.
 
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