Pinking, knock, and octane rating query?

[snerkler]

they run the bike with unleaded to one cylider and BP ultimate to the other cylinder and show the difference.

http://youtu.be/Nkx02U8lJTg

That's quite interesting. I assume they'd biased the study though, and that was quite extreme?

 

[dongleplonk]

Ive just put shell vpower in my Gs1200 and now I get severe pinking from the left side cylinder. Previously I used Esso 97 Ron and that was ok.

Sure the knock sensors are not working then?

 

[dongleplonk]

...surely the knock sensors are not working then?

 

[dongleplonk]

Having read up a little more, higher octane fuel (Shell VPower) should have less of an inclination to cause pinking/knocking!

Wtf is going on? How come I'm getting pinking when using a higher octane fuel rather than a lower one?

I guess this points more to the coils (secondary or primary??) than the knock sensors then?

Any help appreciated.

Btw, the bike has done 2500 miles. 2011 1200 GSA.

 

[Myke Rocks]

A serious question

Are you revving the bike enough?
If you are lugging along pulling a high gear with low revs on the bike, & you open the throttle, the bike will pink.
If you drop a gear & rev it a little more, it will cease to do so.
Having said that, if it has started to pink, it retards the ignition & keeps it retarded until next restart, so the bike is dopey till then.
I run on least expensive fuel even though tank label suggests 98 octane. OK, so I lose a (very) little power at top end, but so what!

Myke

 

[dongleplonk]

Are you revving the bike enough?
If you are lugging along pulling a high gear with low revs on the bike, & you open the throttle, the bike will pink.
If you drop a gear & rev it a little more, it will cease to do so.
Having said that, if it has started to pink, it retards the ignition & keeps it retarded until next restart, so the bike is dopey till then.
I run on least expensive fuel even though tank label suggests 98 octane. OK, so I lose a (very) little power at top end, but so what!

Myke

Hi Myke

Sure am revving it! Pinking starts to be audible from 3K revs. Then is at it's loudest between 4 and 4.5K. Then diminishes to full revs (or about 6.5K anyway).

So pinking is loudest through the most useable power rev range.

Yep - the knock sensors are sensing the pinking and doing their job - retarding - pretty much as soon as I get into 2nd or 3rd gear and as you say, from then on its dopey. Thats the most annoying bit - apart from what damage I imagine is occurring to the engine!

In the past I have been running on lower octane (97 RON) and the pinking was less of a problem, now on 99 RON it's worse. So there must be something wrong with the coils. Dunno yet.

 

[Myke Rocks]

Very interesting:

Hi Myke

Sure am revving it! Pinking starts to be audible from 3K revs. Then is at it's loudest between 4 and 4.5K. Then diminishes to full revs (or about 6.5K anyway).

So pinking is loudest through the most useable power rev range.

Yep - the knock sensors are sensing the pinking and doing their job - retarding - pretty much as soon as I get into 2nd or 3rd gear and as you say, from then on its dopey. Thats the most annoying bit - apart from what damage I imagine is occurring to the engine!

In the past I have been running on lower octane (97 RON) and the pinking was less of a problem, now on 99 RON it's worse. So there must be something wrong with the coils. Dunno yet.

Bearing the above in mind, I would ask two more questions:
1: is the bike new? If so, dump it back & complain.

2. If not, are you sure of the fuel you are being sold.
Near where I live, in Camlough, to be precice, there was a filling station which used to dilute the petrol with Parrifin.
Cars went in running great, filled with (relatively) cheap fuel, & left pinking & running like pigs.
Myke

 

[mark2jag]

May I give my 2p worth? Using normal petrol will not cause pinking knocking pre ingiton detonation because of the knock sensors. When knocking is detected the fuel ratio is enriched and the knocking stops. I'm not sure but in extreme conditions I think that the timeing is retarded. There are certain things that lead to pinking, advanced spark, high compression ratio, grade of fuel, general design of power unit, maner of operation, air fuel mix, and carbon build up or a combination of these. In a modern 4 stroke there is very little we can adjust any more so maby look at the maner of operation. Going up a hill in too high a gear with the throtle wide open is a classic way to indudce pinking. In our modern engine electronics take over and the secondry butterfly is closed mixture enriched and the rider is none the wiser. I think. JJH

the only thing here thats retarded is ME as i dont understand a fcuking word of it...........

 

[dongleplonk]

Turned out to be blown head gasket! Sucking in air making the mixture leaner. Fixed.

 

[duckspeed]

Your bm will run ok on pretty much any unleaded, as knock sensors will shift ignition timing to manage detonation. What I would say though is if we see any poor fuel issues in our workshops the fuel is usualy from a supermarket or other suppliers of cheap fuel. Get what you pay for, personaly it's Shell for me.