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knocking sound

3K views 12 replies 6 participants last post by  mrdilligaf 
#1 ·
i bought a new zx-12r about 4 months ago, it has about 1800 miles and now has a knocking noise at idle after it warms up. I have been to 2 dealerships, the one I bought it from said they couldnt hear it and the second one told me that it was the injectors (even though to me it sounds like a knock) is this possible that my injectors could make this sound and if so, how can I get rid of that problem!?


any help would be great!!!!

md
 
#2 ·
This may not have anything to do with your problem but anyway, A few weeks back I was hearing a knock just in first gear and only after I started to roll. It was driving me crazy, and it sounded like a rod problem. After changing the oil, checking everything out, it sounded fine for a while then started again. I was sure something was wrong. What it turned out to be was a kinked chain link. I do lots of riding in the rain and a link stuck tight. It was very dry and every other turn it made a clung sound. I cleaned the chain really good, several times, then lubed it and left it over night. Next chance I got I worked every link to make sure it was fine. The clung is gone. I hope your problem is that simple.
 
#3 ·
Sometimes when I first start up the bike I will hear a fairly
loud metallic clunk, sounds like it is from down low on the motor.
Sometimes it does it once, sometimes twice, sometimes not at all :? \
It only does it when cold and when I first start it up, usually within the first 30 seconds.
 
#4 ·
Take a Long Screw Driver with a Wooden Handle and hold your hand around it so you can put your ear to the handle without your ear touching the handle. Put the Blade of the screwdriver on different parts of the engine until the sound is the loudest. Let us know where that is! Check the Cam chain area 1st and the Valve area 2nd and the center of the cylinder
3rd and the crank case last.
 
#5 ·
thanks for replying to my problem about the knocking!

I took a long drill bit and did just that, I could hear the knocking at the injectors alright, nothing in the block...big ass relief!!! Do you have any suggestions on how to get rid of this noise? I asked a guy at the bike shop locally & he suggested maybe changing the pipe to relieve the back pressure. what do you think?

man this is driving me nuts!!!!!!!

thanks for all the help!!

md
 
#6 ·
I guess I am Deaf because I also have to use the tool to hear the injectors. The only reason a Pipe and less Back Pressure will have anything to do with you not hearing them is "THE NOISE "The Pipe will be making and nothing else! :d:d
 
#7 ·
How in the ???? could reducing the back pressure on the engine change the sound from the injectors.

1. Its not a direct injection engine, like a big diesel.

I'm not asking this question to you personally but to the dealer guy on crack.

Personally I'd run some injector cleaner through it if you really think its the injectors, injectors can make a huge racket if they get dirty. I've seen it before but not on a bike.

FYI only run the correct (mix ratio)amount of cleaner in a full tank(s).
 
#8 ·
ya, to tell you the truth, I'm not too sure the injectors could even be this loud, I have put the listening tool (long assed drill bit) on the whole engineand can't hear a knock or a tick anywhere other than the injectors. if this were a car, I'd swear the sound was a rod because it sounds like a knock and not the "ticks" a bike usually makes. I had mt zx11 for 4 years, road the hell out of it and never had a lick of trouble from it, I get this bike and this crap happens, bike shops are either too busy to look at it or they tell you some kind of bull crap to try and passify you. I can hear this 20 feet from the bike yet MAX PITTS up in Peru In. says he can't hear anything out of the normal. I dom't know enough about the bike to start tearing into it and there is no one that I can find in Greenwood In. who has one to talk to. Any of you guys live in indiana? Hell, I'll bring it anywhere to see if someone can help me figure this thing out! :evil: :evil: !

md
 
#9 ·
On the day at the track from the pic, I flat spotted a cam and wore out a rocker, in the hotel parking lot I adjusted the valves and rode it home 180 miles.

It knocked until I cinched up the gap. it could be a valve problem, missing shim?

If it is truly knocking (rod) it usually won't run long. With so few miles it sure shouldn't be a piston slap.

Honestly Id work from the outside in. Injectors, valves rod bearings.

I had a diesel car that plugged an injector in '91, I swore that thing dropped a rod it hit so hard, my dad took it out and rodded it a few miles, cleared right up. If it is a rod knock it will progressively get worse until lock up.

Hows the power? If normal it shouldn't be the pipe. It could be a valve though, you won't notice its relatively small drop in power on 1 valve very easily especially on this powerful of a bike.
 
#10 ·
power seens fine, only hear noise at idle or slightly above. I getting ready to go down to the shed and poke around with it to see if I can isolate it. makes me wish I'd bought something else. Damn it, you spend this kind of $$$ on a bike, you think you'd get your $$$$'s worth!

hey, thanks for your help, I'll let you know what I find if anything, ok to write you personally?

md
 
#11 ·
Sure you can email me. I'll help as much as I can from ND.

I know its really irritating, the good news you have the warranty, part of that $$$ price.

No matter which bike/vehicle you buy there is a chance of something going wrong, its a machine and assembly line machines have probs no one finds until the end user.

I have heard of every manufacturer having the same problems.

At the US factory, (I know the 12 isn't made in the US) all they do is assemble it, fill it with fluids put it on the dyno check its within a range of specs, all lights work, shut down drain fluids, crate/ship.

Every factory I've ever toured does the same thing.

There is no way to find the hidden faults.

I take bigger risks, I buy used. So far so good, on all my vehicles, no warranty, my bike has a small injector/valve tick, put 2000 miles on no worse no better.

Did my bike have a bigger problem in the 2390 miles I didn't drive it? Don't know. Previous owner never told me.
 
#13 ·
re; knocking noise

finally got someone at a bike shop to actually hear the knock, he said that the injectors are out of sinc and that he would fix it or not charge me for it, also doing my whole 600 mile check up over again to make sure nothing else is wrong...

thanks for all the replies and help, I came to the right place!

dilli
 
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