WarriorOnTheEdge
Parking Attendant
Posts: 17
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posted April 14, 2013 04:18 AM
2012 ZX-14R Low end roll-on rattle?
Just recently, I have noticed a noise that seems to come from the air box or top of the engine when rolling on hard from anywhere between 2500 to 4000 rpm. The noise stops sharply as you get above about 4000. I can't remember if it made it before.
Light to moderate roll-on -> no noise.
Hard roll-on from above 4000 -> no noise.
Operation and power seems perfect in every other respect.
Completely standard configuration.
Anyone else ever notice this?
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ZX-14R ABS SE 2013 (Yes - I now have two!)
ZX-14R ABS 2012
GPz1100 (ZX-1100A2)*
Z1R-II*
Z1R**
*Sold **Borrowed by persons unknown and not yet returned!
  
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WarriorOnTheEdge
Parking Attendant
Posts: 17
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posted April 14, 2013 02:17 PM
I am guessing that slapping the throttle valves wide open at below 4000 rpm allows more noise from the inlet valves to come back out through the air box ... until either the speed of the incoming air swamps the noise, or the secondary flies decide that they don't need to be so far open.
Now that I think about it I think I remember hearing this from when the bike was new and just forgot.
I would still be keen to hear from anyone else who hears this or has another idea about what causes the noise.
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ZX-14R ABS SE 2013 (Yes - I now have two!)
ZX-14R ABS 2012
GPz1100 (ZX-1100A2)*
Z1R-II*
Z1R**
*Sold **Borrowed by persons unknown and not yet returned!
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justoyz2
Zone Head
Justoyz Racing
Posts: 858
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posted April 14, 2013 10:37 PM
do you have the traction crontrol on?
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2012 zx14R-blue,2012 zx14R-black, 2014 zx14Trbo, 2011 zx10R, 2007 zx10 Turbo.....
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hagrid
Expert Class
Posts: 373
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posted April 15, 2013 02:36 AM
Mine does it too and I'm sure its detonation. I stopped lugging the engine.
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blue 14R
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WarriorOnTheEdge
Parking Attendant
Posts: 17
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posted April 15, 2013 05:24 AM
I have tried it with TC on and off - the rattle is still there. I imagine it is less pronounced with TC off but can't be sure.
Detonation ... hmmm. I will stop lugging my engine too!
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ZX-14R ABS SE 2013 (Yes - I now have two!)
ZX-14R ABS 2012
GPz1100 (ZX-1100A2)*
Z1R-II*
Z1R**
*Sold **Borrowed by persons unknown and not yet returned!
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Greggy
Expert Class
Posts: 150
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posted April 15, 2013 05:56 AM
It's definitely detonation as mine has done it from day one, and it's worse on the lower 95 octane unleaded fuel compared to the higher 98 octane unleaded we can get here in Oz. Also it's worse (or should I say more noticeable) when the engine is hotter and/or under extra load such as with a pillion passenger on board which also points to detonation.
Luckily its only very slight and only occurs for a moment so damage is unlikely.
I actually think the 14R is right on the limit (or perhaps slightly too high) of the acceptable compression ratio these engines can tolerate on the street. If anything KHI should back it down a few points for 2014 as the power drop wouldn't be noticeable but the avoidance of detonation in all situations would surely be a good thing.
Greggy
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2012 ZX-14R ABS - Spark Black - Two Brothers V.A.L.E. Carbon slip ons P1X tips - Powerbronze DB screen.
1990 ZX-10 Ninja - Megacycle stainless steel mufflers - gear-sack rack - tinted screen.
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Seno
Pro
BANNED FOR LIFE!
Posts: 1230
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posted April 15, 2013 07:40 AM
Check your fairing bolts...... It's happening above 4K rpm but you can't hear it
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2012 Black 14R -> Completely done!
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WarriorOnTheEdge
Parking Attendant
Posts: 17
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posted April 15, 2013 04:08 PM
@Greggy - what you are saying makes a lot of sense.
Fortunately this doesn't occur often. In fact I only noticed it a couple of times when going very steady (say 3000 rpm) and then deciding to roll-on for some reason (a big straight usually) and then quickly slapping the throttle wide open (and initially that was just to see what would happen).
I thought in these days of sophisticated electronic engine management that it wouldn't be possible for the operator (rider) to create an abnormal combustion situation like this. The 14 doesn't need high revs to operate smoothly at low speed so I expected to be able to just "go from there" i.e. slap the throttle open.
Most engines complain a bit when stood on from low revs. As far as I can tell this doesn't happen at all over about 4500 rpm on my 14.
Given that it is what it is, the obvious treatment is to open the throttle more steadily when rolling on from lower revs and if you really need hyperspace right now then downshift. To quote hagrid - stop lugging the engine!
My main concern was that there was no special problem with my 2012 engine prior to warranty expiration and that I haven't broken or stretched anything during various red-line exploits.
I guess the engineers made the compression ratio as high as they could to wring out maximum performance - but as you say an engine that avoids detonation under all conditions would be a good thing!
____________
ZX-14R ABS SE 2013 (Yes - I now have two!)
ZX-14R ABS 2012
GPz1100 (ZX-1100A2)*
Z1R-II*
Z1R**
*Sold **Borrowed by persons unknown and not yet returned!
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