did a search on this,

[98pacecar]

''recommended octane for Valkyrie'' 

N' came up with zero posts..   

Does it require premium, errr,,, is regular ok?   ???

[giff]

Regular gas 87 octane. Higher octane is a waste of money.

[Patrick]

Regular is fine and it'll start easier on it in the cold. However if you put this monster up for the winter, non-ethanol would be better for storage with fuel treatment. In many parts of the country non-ethanol can only be found in higher octane.
If you have an after market trigger, you may need a higher octane. If you hear any spark knock, thats a good indication.
OK, just saw where you are. You'll probably be driving this monster around all year.

[98pacecar]

Ok that's good, as I just did a mileage check,, n' I'm gettin 36.5 MPG. 

Kind of a drop,, from my Pacific Coast's,,, 49..

But pretty damn good,, considerin da power da fat girl,,, puts out...   

[Bone]

Wait until you get used to the bike. It's difficult to drive efficiently twisting the throttle just keeps happening.
MPG will decrease the more you ride you can't stop smiling.

[Hoser]

Owners manual recommends 87 octane.  I don't think higher octane will hurt it, though.  I know mine runs fine on 85 octane high elevation fuel in Colorado. Went through Kansas with 85 octane and couldn't tell the difference on the way home.  Hoser 

[Relax]

The instruction book says 87 octan, but that is for a standard version. If you replace the trigger wheel or adjust the ignition other ways,,what then? ???

[Bighead]

Well I know that I only put high octane in mine don't know if it is right or wrong and that is all I have ever ran in either one. I have a buddy that won't put anything but 87 in his and another that uses mid-grade and we all need a fill up at the same time so I don't know of any benefit one way or the other.

[Jess from VA]

The instruction book says 87 octan, but that is for a standard version. If you replace the trigger wheel or adjust the ignition other ways,,what then? ???

Then you may (or may not) need higher octane to keep from knocking.  Mine (with a trigger wheel) did.

[98pacecar]

Well I know that I only put high octane in mine don't know if it is right or wrong and that is all I have ever ran in either one. I have a buddy that won't put anything but 87 in his and another that uses mid-grade and we all need a fill up at the same time so I don't know of any benefit one way or the other.

Da guy, usin da,,, regular,,,    spends less,,,,,,,,,, money...   

[Patrick]

The instruction book says 87 octan, but that is for a standard version. If you replace the trigger wheel or adjust the ignition other ways,,what then? ???

Reply #2. With advanced ignition timing, the octane may have to increase. The way to check is to cruise along in top gear at low engine speed, open the throttle aggressively and listen to what the engine has to say. It can be very hard to hear, but, if you hear the engine argue with what you have just done [ spark knock/ ping/ detonate] then you need a higher octane fuel to slow down the flame front/combustion.

[Bighead]

Well I know that I only put high octane in mine don't know if it is right or wrong and that is all I have ever ran in either one. I have a buddy that won't put anything but 87 in his and another that uses mid-grade and we all need a fill up at the same time so I don't know of any benefit one way or the other.

Da guy, usin da,,, regular,,,   spends less,,,,,,,,,, money...    
True but I think a HP engine needs Higher Octane for Max performance (I could be wrong I remember being wrong once before ) I do have a timing advance on my 97.

[Patrick]

Well I know that I only put high octane in mine don't know if it is right or wrong and that is all I have ever ran in either one. I have a buddy that won't put anything but 87 in his and another that uses mid-grade and we all need a fill up at the same time so I don't know of any benefit one way or the other.

Da guy, usin da,,, regular,,,   spends less,,,,,,,,,, money...    
True but I think a HP engine needs Higher Octane for Max performance (I could be wrong I remember being wrong once before ) I do have a timing advance on my 97.

I'm not trying to be argumentative, just informative.
Lower octane fuel contains more energy in BTUs per same size/volume than higher octane. Low octane fuel burns faster than high. The faster fuel can burn and travel peacefully across the combustion chamber the better and the more power the engine will develop. A lot of things enter into this happening though. If the fuel burns to quickly and/or is ignited too soon, the fuel burn/flame front doesn't travel peacefully and the spark knock you hear are flame fronts separating and colliding and reducing power and causing damage depending on its severity.
So, does it hurt to use higher octane fuels than needed. Nope, not within reason. In some cases it is more beneficial in that some expensive fuels [ high octane] have more additives that help with cleaning. If an engine is hard to start in cold weather, use a lower octane fuel, it'll help.

[98pacecar]

As an aside,,, how would I be able to tell if the bike I just bought,,, has an aftermarket ignition add on?     

[Patrick]

As an aside,,, how would I be able to tell if the bike I just bought,,, has an aftermarket ignition add on?     

What add-on are you referring to ?
An IS ICM on your STD/Tour is a change. The side cover has to come off and the part number examined.
A trigger wheel check requires the timing cover to be removed. Without removing the front belt and pulley the only way is the trigger teeth. The original has squared off teeth. The aftermarkets teeth are more pointy and rounded. If the pulley is removed, the aftermarket trigger will be solid and not slotted, and have a 004 or 006 stamped on it for the amount of advance.
The original trigger can be altered/filed and then the key will be about 1/32" different than original.
There is another ECT mod than could be made.

[98pacecar]

Thanks, as I feared the lay out of this motor changes everything..   

On inline 4 or 6's,,, Two screws, pull a cover, n' bingo yer lookin at yer ignition,,, pick ups..   

I was curious, but,,,  don't really need ta know,,,,,,,,,,,,,,, DAT bad...     

[Gryphon Rider]

If the fuel burns to quickly and/or is ignited too soon, the fuel burn/flame front doesn't travel peacefully and the spark knock you hear are flame fronts separating and colliding and reducing power and causing damage depending on its severity.

Almost.  It's not that you have flame fronts separating, but that a separate flame front is created by a separate ignition, and these flame fronts collide.  When the pressure of a gas (as opposed to liquid or solid) is increased, its temperature increases.  When the pressure increase caused by the spark-plug-ignited combustion raises the temperature enough, it can ignite the air/fuel mixture that hasn't yet been reached by the initial flame-front, causing a second flame-front.  When the two flame fronts collide, a pressure spike occurs, and is heard as pinging.  This is what is called detonation.

[Patrick]

If the fuel burns to quickly and/or is ignited too soon, the fuel burn/flame front doesn't travel peacefully and the spark knock you hear are flame fronts separating and colliding and reducing power and causing damage depending on its severity.

Almost.  It's not that you have flame fronts separating, but that a separate flame front is created by a separate ignition, and these flame fronts collide.  When the pressure of a gas (as opposed to liquid or solid) is increased, its temperature increases.  When the pressure increase caused by the spark-plug-ignited combustion raises the temperature enough, it can ignite the air/fuel mixture that hasn't yet been reached by the initial flame-front, causing a second flame-front.  When the two flame fronts collide, a pressure spike occurs, and is heard as pinging.  This is what is called detonation.

Yep, what you said. What I said was a simplistic description just for brevity. Spark knock, ping and detonation are one and the same as mentioned back in post #10. Not to be mixed up with pre-ignition.

[whitestroke]

My Big 6 cylinder 2 stroke, 225 H.P. outboard boat motor ran noticeably better on 2+month old fuel. then fresh fuel. Never could figure that one out.

[Patrick]

My Big 6 cylinder 2 stroke, 225 H.P. outboard boat motor ran noticeably better on 2+month old fuel. then fresh fuel. Never could figure that one out.

How old is that engine ?  And, are you using plain ole auto fuel or non-ethanal 90 octane marine fuel ?

[Chiefy]

When I got my bike, the carbs were gummed up, although she was ridable.  It ran WAY better on premium.  After the clean up, I notice no difference between 87 and premium.  I do however, notice a little difference between 10% and straight gas.  The non ethanol happens to be midgrade.  I'm blessed that I have 3 or 4 stations nearby with non ethanol gas.

[Ricky-D]

Yeah, it's a real thing, keeping track of all the gas stations that have the signs out saying they have NON-ETHANOL gasoline.

And on longer rides I go online to see where some non-ethanol stations are located along the planned route.

Here's the link:  http://pure-gas.org/index.jsp?stateprov=SC

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