Engine hesitating/stalling

[Mustang]

My wife said she was accelerating and the throttle started bucking. I test rode and I was at 2500rpm constant speed and the bike started pulsating. It Acted like the engine died then started, this happened it three sets in quick succession to me. Then it was fine for a half hour. We have had it to the dealer twice before and they replaced the plugs once. The bike has only 3000 miles on it in two years.

It also side on my wife while she had the clutch in approaching a corner.

Anyone aveany ideas?

Thanks in advance
Phil

 

[ARKNT]

Did the dealer replace the plug caps when the plugs were replaced? That has been an issue for engine miss. There is a dealer notice on it.
I'm not sure that your wife's NT matches the symptoms exactly though.

Brad

 

[RedLdr1]

Welcome to the forum. I would start with the Alert on the spark plug caps as well...

 

[Mustang]

Wow, this help is great!

I keep telling my wife to run the rpm's higher but she is not aggressive on the rpm's. However, even with this the engine shouldn't die like this and restart.

Thank you very mch, I will talk with the dealer on Tuesday.

Phil

 

[Phil Tarman]

Keeping the revs above 3,000 feels agressive if she's been riding a bike with a torque curve lower in the rev range. I felt OK on my Connie if my revs were above 2K, but on the NT, I definitely want them above 3K. If you roll on full throttle down around 2K rpm, it does feel as if it cut out and sometimes it will give a mighty clunk and then die.

My NT had a Throttle Position Indicator low voltage that made it run pretty badly for a few miles. I got to the dealers and it ran just fine after I switched off and then back on, but the computer holds a history of any previous faults and so they could tell what it had been. They ordered a new TPI and replaced it, but they also replaced the plug caps at the same time. It's never happened since.

 

[dnktng]

Phil,
The spark plug cap issue has been seen with high ambient temperatures and stop n go traffic, with engine idling. I'm guessing your in Illinois, and not sure how hot it is there, but it may not be "hot." And being at 2500 rpm is a little above "idling."

I'm not trying to talk you out of the spark plug cap being a possible cause, but keep an open mind. I'd still get the original spark plug caps replaced because it is cheap, and they are a known problem. I replaced mine without having any problems. And do keep the rpms up, especially in 5th gear, or it will chug and buck.

Are you seeing anything else when it starts pulsating? A re-start of the meters like you turned the key off and back on? Is the MIL coming on, even momentarily? Is the gas fresh? ...or could you have gotten bad gasoline?... water in the tank?

Again, get the new spark plug caps because that has a good chance of being the problem. Hope you don't have an interrmittent electrical problem.

Good Luck.

 

[EX Winger]

I may be all wrong, but I would think water / condensation in the fuel as a thoughtI would try a partial can of HEET / denatured alcohol to help eliminate any condenation and then a good injector cleaner added to a full tank of gas and run it a good two hundred miles before shutting it off and then refill again, if it is going to be parked long with out riding always park it full of fuel.

 

[charlie b]

When mine did that it wasn't the spark plugs or the caps. One of the injector connectors had come loose. It was an intermittent condition. Just snapped it back in place and it has been running another 10k miles without a hiccup.

 

[taldric]

The sidestand it up securely, right?

That's a good thought... The sidestand sensor could also be broken or shorting.

 

[charlie b]

When mine did that it wasn't the spark plugs or the caps. One of the injector connectors had come loose. It was an intermittent condition. Just snapped it back in place and it has been running another 10k miles without a hiccup.

Forgot. When the dealer looked at it the first time they couldn't find anything wrong. Second day they had it they finally figured it out.

 

[Mustang]

Thank you all.

It did act like the key was turned off then back on but it was milliseconds, much faster then you could move the key. I thought about bad gas when this happened last year and did put heat in the tank along with fuel injector cleaner and premium fuel, that was burned off and still had intermitent issues back then. This year it's the same thing so I think it's not the gas though this tank is last years gas that I am burning off but I had put stabilizers in it and it was only three months.

Yes I am in Illinois and its modestly cool 50's and 60's so far.

Thanks all

Phil

 

[Lorien]

If you can tell us 2500 rpm in which gear please. In fourth or fifth the bike will not be happy and buck like a bronco especially fifth.

A little occasional something to take the water out of the fuel has been recommended by Honda to the dealers. Not everyone has seen this. Could help. Honda product is good.

I'll assume the plugs they pulled looked Ok? They can foul very quickly sometimes with a too rich mixture. Not something I would expect unless the auto choke is in error.

Spark plug caps have been an issue for a few and the bulletin is out there. Have dealer check with Mother Honda if he is unfamiliar.

 

[MAC]

Welcome aboard.

 

[Mustang]

Had it out yesterday and it was in 5th at 2800 going smooth and steady for about 3 miles it started bucking. Then later I was at 3200 and pulled the clutch in and rolled off the throttle and it died straight out, rpm's whent straight to 0, never tried to idle. Thursday the dealer is looking at it.

 

[1fastbob]

Wonder if it has a bad fuel pump or something in the tank blocking the fuel pick up?

 

[Phil Tarman]

Had a tree frog in a 59 VW sedan do that once. Replaced everything in the fuel system and electrical system (including the carb and the fuel pump, distributor, coil, points, spark plugs and wires). No change at all except the distance till the engine died got shorter and shorter and shorter.

Pulled the tree frog out and replaced the petcock and filter screen and never had that problem again.

 

[Lorien]

From the Honda NT700 service manual:

Engine stalls, hard to start, rough idling:
Check the idle speed,
Check the IACV
Inspect the fuel supply system
also
Restricted fuel feed hose
Contaminated/deteriorated fuel
Intake air leak
Faulty IACV
Restricted fuel tank breather hose
Faulty ignition system

IF I am reading this right these could be occuring and no error code show up on the display. Have to admit I don't have a clue what the IACV is.

 

[charlie b]

When the cap on my fuel injector was intermittent it did not throw a code either.

 

[1fastbob]

IACV = Idle air control valve. Pretty sure that is not the problem.

Could also be a kinked or plugged fuel tank vent hose. To determine if the vent is plugged or kinked....ride the bike with the fuel cap slightly open and not latched and see if it stops running. This will require a key in the fuel tank filler cap and the ignition switch.

 

[Rich]

Dirty fuel filter?

Good thought. I've had this happen in a couple of vehicles. I had a Subaru for which it was a recurring problem. My GL1000 had this problem once.

Then there were the rats that chewed on my ST1300 harness that produced different (though equally undesirable) behavior. I'm thinking this'd be less likely in the NT, though. The ST had a fine little homestead location between the cylinders. I don't think there is such a warm, cozy spot in the NT.

I occasionally run my NT below 3000 RPM. Not a big deal if you don't ask much of it in that range.