Happy New Year everyone. I have a 2012 ZX14R with 22000 miles. I just had the spark plugs replaced by the dealer. I took it for a long ride and everything was fine. On the way back home I revved the engine to 10000 rpm then the bike started to backfire the run sluggish and backfiring on all gears and much more on the 3rd gear. It felt like it was running on 3 cylinders and I also hear now a ticking noise. I kept driving it for another 20 miles to get back home. Any idea what could have happened? I purchased the bike with less than 2000 miles on it and had it for 7 years. I take really good care of the bike and all the services are done on time at a dealer shop. I just moved to LA and took it to a new dealer to have them replace my spark plugs. Do you think something came undone? I really appreciate some insight here. Thanks!
Coil stick could have gone bad or the connector came undone?? causing cylinder not to fire and unburnt gas in exhaust is burping up
If you have an IR temp sensor ($20 from Harbor Freight) start the bile and check the temp of each exhaust tube, if one is cold and others are hot that tells you something is wrong. The min wage knuckle draggers at whatever shop you took the bike to in LA to replace the plugs could be an issue. Also recently there have been reports of counterfeit iridium sparks for these bike causing problems
Good luck and let us know the test results
Perfectly Set up '06 dead and gone New BBW '14 14R
It felt like it was running on 3 cylinders and I also hear now a ticking noise.
My guess would be a spark plug is loose and about to blow out under compression. I have heard of that happening. Maybe it has already happened. Check all spark plugs with a Kawi spark plug tool...the one that came with the Gen1 tool kit.
I sure hope a spark plug wasn't left loose and blew out taking the threads with it. If so, make the shop pay for a new head and the labor for a top end job.
As fast as it started, turn it off. This is with a cold engine. What you want to find is a cold header pipe near the head. Closer your fingers are up the pipe, that flamefront heated the pipes more near the exhaust port. All 4 warm, not a stick, not a plug, not an injector.
Take the bike out again and do no rev in neutral or with clutch pulled in at speed. Load the engine thru the gears. If it sputters, keep the throttle open till it clears. 1st and 2nd gear should clean whatever off the plugs. I'm thinking of 'this side of the speed of light' is the entry. In other words, the telemetry's input vs. rpm to wheel speed, it was computing the best calc'd answer math wise. In other words, you may have loaded it up some.
Tick wise, you have to determine if it's valve train tick or spark tick? In the dark garage with a flashlight for a helper, but beam is deflected away from the bike. Your long screwdriver is going to have the metal tip hover over the spark stick at close range so the spark jumps. Your handle should prevent shock. So if you can hear it on either side, play with those two sticks to see if it will induce a jump.
By twisting the stick body, simultaneously press down so maybe its not seated home. Do that first while the bike is cold. Then start it. Tick gone, and you sunk the stick down more, there you go.
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You'd hear the compression out of the plug hole. Like a lawnmower engine with the exhaust off. My guess is no if tick is mentioned. Only a wobbly stick knows for sure.
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Thank you all for your replies. Much appreciated. I took the bike back to the dealer who changed the spark plugs for me and they just gave me some bad news :(
After they had the bike for over a week to run some tests, they informed me that one of the cylinders had no compression and the bike was running on 3 cylinders and they are 99.9% sure I've bent the valve(s) for that cylinder :(
I don't know how i could have done that and the explanation was a bit over my head. Just a background on my bike, I don't have a PC, didn't remove the rev limiter and no flash. Every thing is stock except installing a Brock's slip on exhaust, and installed a HealTeck quick shifter (no auto-blipper) a few years ago.
The mechanic told me that this could have happened if I had the bike high in the rev on one gear then I shifted to a lower gear, that could cause the issue regardless if there is a rev limiter or not. I always pulled hard and revved the bike high then down shifted to engine break. What could I have done wrong this time? Anyhow they quoted my $2000 (parts and 9 hours of labor @$125/hour) to get it fixed.
Any thoughts on what I can do to avoid this problem in the future will be highly appreciated. Thanks again for taking the time to discuss this issue with me.
You sure don't hear this kind of thing too often. I'd be concerned this would happen again if I had to fix that engine. It did it once, it will do it again unless....
I take really good care of the bike and all the services are done on time at a dealer shop.
Did they do the valve clearance adjustment? If not, I'd say you're ok. Never heard of an engine suffering damage from not doing a valve clearance adjustment. If they did do the valve clearance adjustment, I can see how that might cause valves to collide with the piston. If simply downshifting at too high of an rpm can do it, I'd sure think adjusting clearance too tight could do it.
Backfires on every stroke. Bent exhaust and out the pipe is the sound. Plug has to physically look perfect. Can still spark and flame the fuel. Injector does not know the compression is out. Spark does not know comp is out. If diagnosed with a simple plug read or pull the exhaust pipe and make sure the valve is still there.... yeah, gaskets, valve, labor would cover it. No cracked valve guide until they tear it down. So they must have checked that the engine is not damaged. Because if you look at the square line around the head, that's $2,200.00+ for just the damaged head alone. Bent valve is just replace and check seat angle for damage.
... this could have happened if I had the bike high in the rev on one gear then I shifted to a lower gear, that could cause the issue regardless if there is a rev limiter or not.
I could see this occurring. For demonstration purposes, peak rev limiter setting is 10.5k, and 200 more rpm tags the piston. Peak torque is 9k. Any rpm past that is a diminishing return. The idea of any more rpm that revs past the limiter is trying to save the engine from damage. At that high an rpm, this is where spring bounce starts to override the timing of the piston speed going up and down. All it takes is the one time the piston is heading to top dead center, the spring is bouncing the valve like a pogo stick on steroids, and when the piston has nowhere to go but up, it pushes the valve up and bends it. This baby runs on close tolerances. If that's all it was, consider yourself lucky. You're done with this extra rev shit or get the wallet back out, if you get my shift.
I always pulled hard and revved the bike high then down shifted to engine break. What could I have done wrong this time?
Some think the higher the rpm the more getup and go happens. You don't need to rev that high chasing torque. I'm a short shifting bottom feeder. I never took this bike over 7k. The front end comes up at about that rpm. I'm too old for thishit. Wait a minute, you said, 'this time?' I'm trying to imagine you are making the engine scream at the raggedge of the limiter, revved it that one time for the engine braking and when that lower gear revved the engine higher, meaning, 'mechanically geared' past the momentary spark delay, and/or the injectors remaining shut off during that one cycle = Tag!
I'm old style so I have nothing new to offer. I do no use the clutch to shift. I do not add hours adding extra revs so the parts wear out faster. I keep the rpms low and short shift. I do not downshift every gear to a stop. I collect those gears when coming to a slow stop. I'm clunkless to 1st. I time my balls to my head to my toes to the hand and time that low rpm blip. I have a very small window opened to time the downshift or I missed the widow altogether = RPMatters.
* Last updated by: Hub on 1/20/2020 @ 11:58 PM *
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Valve doesn't bend unless it contacts the piston top, usually from timing chain jump/slip/break. Over revs overstress the loaded parts like con rod bolts, con rods piston thru pins. Valves tend to float open at over revs due to time to close less than time of cam lobe to open
Perfectly Set up '06 dead and gone New BBW '14 14R
The forensic would pan out to having both valves tagged. My guess is the exhaust side with no rhyme or reason. Ticking and 20 miles added is that the keepers didn't let got or the piston can pop the face off and those get jammed into the piston dome and sit there. Ticking is excessive shim gap. Valve face is not sitting flat.
And there's no shame explaining you were around redline while shifting. I've seen a few engine failures. Some under me, some on the dyno. I can explain each one. You're just going to have to dismount and walk yourself thru it and lay out the debrief. Thinks like; at what rpm do you think you were at when it happened? What gear were you in? Did the back wheel hop?
I don't know about this.
Valve doesn't bend unless it contacts the piston top, usually from timing chain jump/slip/break. Over revs overstress the loaded parts like con rod bolts, con rods piston thru pins. Valves tend to float open at over revs due to time to close less than time of cam lobe to open
See, we have a skeptic. Let's say Mic has done this a lot. All it took was that one time the downshift caught him out. Can't be a chain jump or the next round of valves would have happened on the next cylinder fire. Can't slip, especially that high an rpm or it would grind and again, lots of tagged valves. 20 miles home said it didn't break.
Tormenting the motorcycling community one post at a time
Why did you have plugs replaced at 22K? Seems a little strange, normally replacing them at 15k valve adjustment is good. Was there a issue?
I'm always suspicious when work is done on a bike and bike blows up shortly after. Can't think of what they could of screwed up to cause this problem. Stripped plug threads, cheap insert melts drops into cylinder or done wrong, plug holes not cleaned before removing plugs crap drops into cylinder I don't know.
These motors are bullet proof. Hitting red line is a routine ride and always puts a smile on my face. Bike does GREAT smokey rolling burn outs too!
My only rear brake is engine braking. I engine brake heavy.
These motors can take it, Have fun, beat'em like a red headed step child!
These motors are bullet proof. Hitting red line is a routine ride and always puts a smile on my face. Bike does GREAT smokey rolling burn outs too! My only rear brake is engine braking. I engine brake heavy. These motors can take it, Have fun, beat'em like a red headed step child!
I must agree. I do not try to hit the rev limiter but when I do, I don't worry about it. I engine brake as often as I can sometimes at 7000 rpm or higher. I have missed gears shifting at 10,000 rpm and of course there limiter gets hit there.
