Bad gas? Clogged fuel filter? Other? . . .

This afternoon ~75 miles into a 100 mile ride - I initially felt a very brief loss of power, almost like a mis-fire? was in 6th gear ~75mph ~4000rpm - the momentum kinda throws the weight of the bike forward when this happens. I thought I just hit some sort of irregularity in the pavement and I ignored it. Kept going then did it a few more times - kinda random, 3 or 4 times, then stopped. Okay, now I was convinced something was going on. Tried varying speed, shifting gears - would run okay for a while, then maybe a few 'bumps' then back to running normal again. Speed and gear didn't seem to make any noticeable difference, but if I pulled in the clutch and just coasted (engine would drop down to idle) I didn't notice it doing anything strange. I never heard a noise like a mis-fire or anything that sounded weird. It's been probably 1,500 miles since my 16,000 mile service. I did get gas yesterday at a place I have been to many times and never had a problem. But then it was only ~5-8 miles slow speed in town before I parked it in the garage. Any body have experience with bad gas or clogged fuel filter in an NC? Where is the fuel filter? Any other things I should look into? Water in the gas? Clogging injector? Any other ideas? Was going to ride it again after work tonight but want to have some ideas of what to think about, look for, try, . . .

The closest thing I've had to that was on my FJR1300. It would run like a champ, and then buck like a horse. No misfiring, just random power loss. Did it for months. I did all kinds of recommended fixes on the FJR forum. Changed the fuel filter, plugs. Drained the gas. Synced the throttle bodies. I even did that forums ever popular jumper for the cable to the engine control unit to enable fuel/air mixture change using the tripmeter buttons on the dash (anyone here figure out that yet for the NC?)
Anyway, all that stuff did a pretty good job of changing squat.
I ran into my friend that had a Yamaha R-1, and he said his did about the same thing. He took it to the dealer and they charged him $50 to clean and tighten the positive battery terminal, and it never acted up again.
I walked right out to my bike, opened up the battery panel, and saw the positive terminal barely attached. Wire brushed and tightened connector, and she ran like a brand new bike.
Good luck!

HueyFE said:

The closest thing I've had to that was on my FJR1300. It would run like a champ, and then buck like a horse. No misfiring, just random power loss. Did it for months. I did all kinds of recommended fixes on the FJR forum. Changed the fuel filter, plugs. Drained the gas. Synced the throttle bodies. I even did that forums ever popular jumper for the cable to the engine control unit to enable fuel/air mixture change using the tripmeter buttons on the dash (anyone here figure out that yet for the NC?)
Anyway, all that stuff did a pretty good job of changing squat.
I ran into my friend that had a Yamaha R-1, and he said his did about the same thing. He took it to the dealer and they charged him $50 to clean and tighten the positive battery terminal, and it never acted up again.
I walked right out to my bike, opened up the battery panel, and saw the positive terminal barely attached. Wire brushed and tightened connector, and she ran like a brand new bike.
Good luck!

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And what do you bet the first thing you do for 16,000 Mile Service is - Disconnect-The-Battery-Cable?

Got in ~130 miles on my evening ride today - symptoms did not re-occur. Refilled the gas tank when a little below half at a different station in a different town - thought that would dilute anything that might have gotten in there. Day before this, the dealer replaced the rear tire as I had worn through to the steel belts again. They put a pressure washer to the bike since I had gotten it pretty grimey - got caught in a downpour in a construction zone a week or so ago - mud, sand, gravel - was an adventure in itself. Maybe they were a bit zealous with that? Battery connections seemed solid but battery strap was not attached.

The pressure washer is a bad idea. That much pressure will force water into places water isn't supposed to get

My first guess too, would be electrical versus gasoline issues. Check to make sure the caps are firmly pushed down onto the spark plugs...

Poor fuel. Similar thing happened to me years ago on a Yammy FZ750. Just a bit of water in the fuel I was informed. Just fill up again and it should cure the problem....(hopefully).

I would think that if it was mis-firing it would throw a code or flash the SES light. It's the yellow engine icon in the cluster.

Sounds more like a fuel issue. Retrace your steps, start with the simple stuff like if you messed with anything (spark plugs, wires, etc). If that checks, check your battery connections. Check battery voltage with a fluke meter both running and not. Chances are if everything is good there, then check fuel related issues. Check fuel pressure, filter, etc (if you have the tools).

I could guess all day long, but without having the bike in front of me and the bike acting up while riding it, it would be hard to diagnose.

Thanks for all the ideas. I have checked some things and will look into others. Plan to ride today at lunch and then after work if it doesn't rain - I'll see what happens.

These symptoms fit electrical to a "T" but don't fit bad gas or clogged filter or the like at all.
IMO/E.

Got two rides in today, ~270 miles total - No problems at all. Still not sure if running fuel through it; or checking, tightening battery connections, spark plug wires, . . . fixed it - but happy with the result. Thanks again for ideas and suggestions.

jelo said:

Got two rides in today, ~270 miles total - No problems at all. Still not sure if running fuel through it; or checking, tightening battery connections, spark plug wires, . . . fixed it - but happy with the result. Thanks again for ideas and suggestions.

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I hate to be an Ostrich head-in-the-sand kinda guy (it's all too easy for me, lol) but heck, every once in a while the good guys win, right?

Maybe it was just some random happenstance that will never crop up again. A period of monitoring, fresh, good quality fuel, maybe a dash of water remover/gas line antifreeze stuff, a scratch behind the NC's ears and a new Farkle treat will be the ticket.

On occasion, the fuel pumps on bikes fail. Poor running would be consistent. On the East Coast you're seeing some E-15 fuel being sold. It goes bad, separating into alcohol and fuel. E15 can dissolve some rubber components.

I have had a lot of gas problems over the last 55 years of riding a motorcycle. Usually because I ran out of gas! Seem to do that a lot.

Here is a link to help you find pure gas (no Ethanol). Also there are links to download both Android and Apple apps for your phone
Ethanol-free gas stations in the U.S. and Canada