Could you better describe the symptoms beyond "surging" for us? To me, that means the engine RPM starts to increase noticeably/suddenly, under constant load and throttle, even though you are not applying more "gas" (turning the throttle).
BTW- You need to check your signature, you say 2008 "Atomic Silver" (which is real silver), that was available only for 2011. I think you mean "Neutron Silver" (light stone-bluish silver).
http://www.zggtr.org/index.php?topic=20250.0
Help! My 08 C-14 is Surging really awful around 4-5K rpm & up. It was doing it at 9k then started doing it at 7K & now around 4K. It ran really Amazing one time/ one day after a fill-up with Costco Gas; I filled up on my way to work & after work, it ran the best she's EVER ran; EVER! It was a cooler evening but the symptoms came back the following days. I drained the tank, removed the fuel pump, cleaned the pump & screen of greenish Algae looking buildup. It improved slightly but was still surging so I installed a new pump, screen with fresh gas & it's still acting up. Next is to inspect the injector screens but I'm suspecting the secondary throttle actuator. I believe it's sticking or worn. I'll clean & lube the secondary throttle shaft & see if that helps because when I back off the throttle, she lunges forward.
Any additional suggestions or insight would be much appreciated.
Sounds like a clogged fuel strainer causing fuel starvation.
The screen is located in the fuel pump ass'y, which is inside the fuel tank. Not too awful to do an R&R but you will have to empty the tank and pull some fairings off before you can remove the tank and invert it. The pump is inside the tank and is installed and removed from the bottom.
Besides the fuel filter, fuel injectors, and fuel lines, also check the vent for your fuel tank.
My thought exactly based on that description he just made.
But he says he replaced the pump and screen (which I assume means the filter was checked too). I suppose it could STILL have a clog. Maybe something in the lines? Hmm. His thoughts on the secondary throttles (butterflies) do kinda fit the symptoms, but I thought that would throw an error- doesn't the bike have a sensor to tell it how open they are?
Thank you all for your input. The fuel pressure regulator is a suspect! I'll try all the suggestions. I have replaced the pump assembly with a higher volume one with new screen/ sock filter. There was Green Algae like deposit covering the sock. I'll do a pressure check. I'm thinking that the injector screens may have the same Algae/ bacteria clogging it. I added some Bellicide to my tank & Techron additive. I'll check the MAP Sensor and inlet/ intake. I replaced the Air Filter with a foam element so airflow isn't an issue.
If I feather the throttle, I can get the bike up to 90 plus but it takes a bit of time. Like a Honda Civic Hybrid. It's gotta be a Fuel Flow issue, I think.
Because it ran so well that one cool evening, I'm wondering if it could be a heat induced electrical issue. I did install some heat blockers in the lower section of the fairings but I doubt that would cause the problem.
The vent isn't a problem here as there usually pressure built up in the tank from the Texas heat. I've never had a problem opening the gascao. Usually I can hear air seeping from the gas cap key flap. Will keep you all updated. Thanks again.
Wow, I was not even aware that there is anything other than an OEM fuel pump ass'y that will fit in a C-14 but if you did replace the entire ass'y with something [non OEM] I am especially suspect of its output.
It is unlikely to be any type of electrical issue IMO because the ignition system is all independent (each of the four cylinders), and generally electrical issues are more ON and OFF than limiting in power / RPM. Hey, it is possible but that is not where I would start looking- again, the fuel pump assembly including the fuel pressure regulator (located inside at the top of the ass'y). Test output with a pressure gauge (usually 39 PSI but check the manual for the actual number), then a volume test- see how long it takes to pump some known volume, such as a quart.
I had this same problem on an Expedition once: it would start right up and idle but adding any throttle was a struggle. A quick volume check showed the pump's output was far short of the normal range and it was not subtle. The bad news is that it was a LOT easier to test than it is on a C-14 as there is a test valve in the fuel line under the hood, and the pump was easy to power-up through the fusebox, also under the hood.
Brian
HERE is a link to another aftermarket replacement pump, a couple guys on the other forum have actually purchased, and ran them, and had nothing bad to say about them at all..that same place sells the filter socks for 3 for $14
https://www.highflowfuel.com/i-23443610-quantum-t35-intank-fuel-pump-with-strainers-for-kawasaki-concours-14-zg1400-2008-2018.html
OK, that makes sense as it is a component kit rather than a fuel pump ass'y. There are very few O.E.M. pumps on the market, I think it is three to be exact, so just the fuel pump is not hard to get. But a complete ass'y, with the low fuel warning, the metal mount and tank seal, the piping and wiring harnesses- I would be amazed if anyone other than the original manufacturer actually made one for a C-14. In fact, most motorcycles with very few exceptions.
According to the list of parts (printed) as well as the colored component diagram, that kit does not come with a pressure regulator. If that is the case, and the O.P. has a bad regulator, his symptoms and experience would make perfect sense because he would not have actually replaced the defective part.
As an aside, I was working at a company that was machining an aspect of an automotive air conditioning compressor and I asked 'for which brand'. The reply was 'all of them'. Not like the olden days, today parts manufacturers often make a component or assembly for 'cars' and it is the truly single source for the entire world. So the 'Chevy vs. Ford' argument is getting watered down all the time 'cause whichever one you choose, they share a LOT of parts / assemblies.
Brian