That air filter looks pretty bad. I would almost bet it got missed. Is the center oily ? Is the oil level correct? Too high a level can do this. One reason to look into servicing your bikes yourself.
I decided to check the air filter today. Keep in mind, it was supposed to have been changed by the dealer when I took it in for one last service prior to the end of my 4 year service package purchased from that dealer. That was at 48k miles and I am now at 60k. Air filter looked pretty crappy for only 12K miles since they "replaced" it. I just ordered a new one a few minutes ago.
Took a look at the ignition coil connections. They looked find. Still tossing around the idea of replacing the coils. They aren't too expensive.
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Last edited by SergeantChuck; 24th November 2018 at 10:13.
That air filter looks pretty bad. I would almost bet it got missed. Is the center oily ? Is the oil level correct? Too high a level can do this. One reason to look into servicing your bikes yourself.
Oil level is good. I changed the oil myself the last time two times since my warranty ran out and the oil was one of the first things I checked when the problem began. I was looking to see if the oil level had raised and antifreeze level had lowered. I have a feeling the filter is the original so it has 60K of debris.
The dark area is in line with the intake snorkel in the airbox so it gets a direct stream on intake air. It has nothing to do with the oil level in the engine.
Update on my situation. The problem has not been resolved but I figured I would list what I have done so far for historical and future troubleshooting purposes.
1. Checked Oil Level
2. Replaced Spark Plugs
3. Replaced Air Filter
4. 3 X Tank of fuel with Seafoam
5. 1 X Tank of fuel with HEAT
6. Replaced Ignition Coils
7. Opened fuel cap while riding to test venting
8. Checked for loose ground wires.
Thinking about checking for a small vacuum. In the old days I would just spray carb cleaners around hoses and listen for a difference in the idle. Any suggestions on how to do that with a bike? Same way?
Good idea. I think it would work to spray around the intake. It could be a loose or cracked vacuum seal somewhere.
Makes as much sense as anything.
JT
I had a similar problem when I serviced my K&N filter I used a aerosol spray that was supposed to be designed for cleaning my O2 sensor that's located inside the air box (the one you have to disconnect when changing/servicing the air filter)
because I was messing around that area when I started having problems (which was almost immediately) I figured it was the O2 sensor,
I ordered a new one, installed it and did the reset buy disconnecting the battery, turning the key on to discharge anything in the system, let it sit for awhile then hooked the battery back up turned on the key, started the motorcycle and didn't touch the throttle at all until after the fan came on (full operating temp) sure enough my motorcycle ran perfect after that.
I did ride my NC for almost a week (around 500 miles with it not running perfectly)
After all that, a week or two later my water temp sensor (controls the radiator fan want bad) my NC had 65k/66k miles when this all happened. Changed the water temp sensor and my coolant and my NC us back to normal.
Good luck, I hope that was helpful
Regarding a possible vacuum leak, I’m posting this is as food for thought, nothing else.
On carbureted motorcycles, you have the carb mixing fuel with the air, then the flow typically passes through a boot to the cylinder head. Any vacuum leaks downstream of the carb introduces more air and leans the mixture. On the NC , the throttle body controls air flow. But, the fuel is injected in the head, just before the intake valves. A leak at the throttle body boot could mess up the accuracy of the computer’s feedback as to how much air is actually entering the engine, but it’s less likely it could lean the mixture on this engine. In closed loop mode the O2 sensor feedback in the exhaust would induce fuel trim to put the mixture back where it should be.
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Just an update. The problem still has not been resolved. I have added something new to the list of troubleshooting steps.
1. Checked Oil Level
2. Replaced Spark Plugs
3. Replaced Air Filter
4. Replaced Ignition Coils
5. Opened fuel cap while riding to test venting
6. Checked for loose ground wires.
7. Mass air flow sensor
8. 3 X Tank of fuel with Seafoam
9. 1 X Tank of fuel with HEAT
The last thing I tried was replacing the mass air flow sensor. Why the mass air flow sensor you might ask? The bike seems to be running a little lean on one cylinder so questioning the air fuel mixture plus I rode home in the pouring rain last week and the bike ran its worst since the problems began. This sparked the idea of either an exposed wire against the metal and the wetness worsened the problem or the mass air flow sensor because I had read of "wet/humid air" causing this affect with a bad sensor. I have ridden the bike 60 miles after changing the sensor and it felt a little better but nothing drastic. Probably just my imagination. I believe there is a cycle the ECM goes through and doesn't necessarily provide new readings immediately which would adjust the air fuel mixture so I will ride a few more days but not real hopeful that it will change things.
I ran into a mechanic friend the other day that is well versed in bike repair. He mentioned that he has dealt with fluttering issues in the past and it was normally two things. A very carboned up throttle body that was not allowing the butterflies to shut fully and a bad ignition module. He said stator but he has never worked on a NC700 and he assumes it does not have a stator but has an ignition module which I confirmed and have found one to purchase.
He recommended I first clean the throttle body, then buy the ignition ignitor module if that does not work. This will be my next step.
If the bike is overheating, has anyone suggested replacing the thermostat? Malfunctioning thermostats can cause all kinds of problems (not just overheating)....
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