can anyone diagnose engine ‘surging’ prob?

[toowired]

greetings my nt700 runs great first half hour. then engine light comes on. from there onward engine ‘dies’ (kinda) then ‘surges’ after i’ve given it throttle for a few seconds. herky-jerky. i mostly ride in first and second gear. problem occurs in 3rd as well.

this is a persistent problem, has happened last 3 times i’ve used bike. it will continue to run as long as i like, but dying/surging issue persists remainder of ride. engine light remains on but is off next time bike started (days or a couple weeks later).

i always refill tank. have tried sta-bil and ‘liquid tune up’ as well.

i have to admit i did let it sit too long (six months?) without starting it earlier this year. since then i’ve run it more often and added a good bit of gas after rides, and ingredients above. but if bad gas i’m wondering why it always runs great first 20 minutes to half hour?

knowledgeable advice appreciated, thanks!

 

[DirtFlier]

You ride "mostly in 1st and 2nd gear"?

 

[Phil Tarman]

It would be helpful to know what the "engine light" is telling you. My bike was doing that and it ended up being the connector to the throttle position indicator. It was an easy and cheap fix.

 

[toowired]

yes. i believe in general it’s better to run at a higher rpm, which i have read is more common in europe.

i seek to upshift between 5000 and 5500 rpm, and cruise at no less than 4000 rpm. higher rpm takes a bit of getting used to, i also have a can am spyder for which high rpms are a must. once you are used to it, it feels like the correct way to ride for the nt700 as well.

there are many beautiful back roads in my area, i am perfectly happy riding them between 35 and 45 mph, which seems fine in 2nd gear.

of course on occasion i am riding 50 mph or above, and then generally use 3rd gear.

the nt700 is a bit underpowered for divided highway use (imo), so i am seldom cruising at 60 or more. personally i love the bike, but i think the nt700 has no business on the interstates. i feel like an underpowered sitting duck.

i am well aware that cruising at too low an rpm is bad for the engine. i am nowhere near redline at my chosen rpm ranges, so i doubt that’s bad for engine performance.

so yes, i’m quite happy enjoying the scenery between 35 and 45 mph, which keeps me in first and second gear a lot of the time. there are a lot of deer around here as well, slower speeds mean less likelihood of hitting one. of course i ‘open it up’ a bit on the occasional straightaway, but that’s less common.

these are strange bikes. not crotch rockets. not powerful enough for true touring. i doubt they attract many daredevils. i’ll morph a piloting expression that has served me well: ‘there are old riders and there are bold riders. but there are no old bold riders ... ‘

i stumbled upon the nt700 when i was looking for an st1300. i love the bike, but i think perhaps i should’ve held out for the larger bike. which is also something of a ‘misfit toy’ in the bike world. crotch rockets kill. i’m not ready to go gold wing yet. i prefer a nice smooth ride at slower speeds. i ride for the scenery and the relaxation

still hoping for some advice about the ‘surging’!

 

[toowired]

It would be helpful to know what the "engine light" is telling you. My bike was doing that and it ended up being the connector to the throttle position indicator. It was an easy and cheap fix.

did you have the same 20 to 30 minutes of smooth operation before the engine light came on? did you have the same surging? i assume other than taking it to a dealer (which i’m willing to do if no easy fix), that there’s no way for me to know ‘what the engine light is telling me’?

 

[dnktng]

that there’s no way for me to know ‘what the engine light is telling me’?

How to read and reset the MIL.

 

[NewTo700V]

When you're out riding and it surges and the light comes on, pull over somewhere safe.

DO NOT shut the bike off for the next step.

Shift to neutral once you're stopped and put the kickstand down. The engine light will then flash out the active code and repeat. Count it and refer to the link dnktng posted.

 

[mikesim]

i seek to upshift between 5000 and 5500 rpm, and cruise at no less than 4000 rpm. higher rpm takes a bit of getting used to, i also have a can am spyder for which high rpms are a must. once you are used to it, it feels like the correct way to ride for the nt700 as well.
there are many beautiful back roads in my area, i am perfectly happy riding them between 35 and 45 mph, which seems fine in 2nd gear.
of course on occasion i am riding 50 mph or above, and then generally use 3rd gear.

the nt700 is a bit underpowered for divided highway use (imo), so i am seldom cruising at 60 or more. personally i love the bike, but i think the nt700 has no business on the interstates.

i am well aware that cruising at too low an rpm is bad for the engine. i am nowhere near redline at my chosen rpm ranges, so i doubt that’s bad for engine performance.

these are strange bikes. not crotch rockets. not powerful enough for true touring.

i stumbled upon the nt700 when i was looking for an st1300. i love the bike, but i think perhaps i should’ve held out for the larger bike. which is also something of a ‘misfit toy’ in the bike world. crotch rockets kill. i’m not ready to go gold wing yet. i prefer a nice smooth ride at slower speeds. i ride for the scenery and the relaxation

still hoping for some advice about the ‘surging’!

Do the test that was suggested above and we will then have a clue on what to suggest. Your description of the bike baffles me however. I know the NT is not a powerhouse, but it is quite happy and comfortable cruising on the Interstates at 80-90 mph! How fast do you want to go? There are many of us who have over 100K miles on our NT's and have traveled to all of the lower 48, Canadian provinces and Alaska and if that's not "true touring" I don't know what is. If your riding style dictates keeping the bike at 5K rpm that's perfectly Ok and it won't hurt it a bit. Hondas like to rev. But I think you would find it a lot more relaxing to ride with the engine at a lower rev count. Unless I'm in hilly country, putting along at anything over 3K rpm is delightfully smooth and quiet.

Mike

 

[NewTo700V]

I know the NT is not a powerhouse, but it is quite happy and comfortable cruising on the Interstates at 80-90 mph!

It most certainly can. Three months ago I did a east coast to west coast run in two days. The main leg was a non-stop 1900 miles in 31 hours before grabbing a few hours of sleep before finishing the last 700 miles. I was probably averaging 80 or higher the whole way. I did the same exact stupid stunt on the return trip a week later. NT was at high revs for hours and hours without issue.

 

[toowired]

Do the test that was suggested above and we will then have a clue on what to suggest. Your description of the bike baffles me however. I know the NT is not a powerhouse, but it is quite happy and comfortable cruising on the Interstates at 80-90 mph! How fast do you want to go? There are many of us who have over 100K miles on our NT's and have traveled to all of the lower 48, Canadian provinces and Alaska and if that's not "true touring" I don't know what is. If your riding style dictates keeping the bike at 5K rpm that's perfectly Ok and it won't hurt it a bit. Hondas like to rev. But I think you would find it a lot more relaxing to ride with the engine at a lower rev count. Unless I'm in hilly country, putting along at anything over 3K rpm is delightfully smooth and quiet.

Mike

you guys rule! so funny, as i was rolling it backwards into garage w kickstand down, eng light was flashing. so now i know i can check that and then check that link. thanks!

once i get surging fixed, i’ll take it out on us1 bypass. i had it on int 84 when i first got it (pre-owned). it ran perfectly but my recollection is it seemed strained at 65 and i felt like a kite whenever an 18 wheeler blasted by me. could be my imagination or just a personal preference but i remember feeling like it was way underpowered for interstate speeds. i felt small and unsafe

 

[ARKNT]

As others have said get the code, decode it to see where to look first.
There have been reported sensors that open (fail) with heat. That is a possibility with your symptom of 20 minute delay till surging.

Brad

 

[toowired]

Do the test that was suggested above and we will then have a clue on what to suggest. Your description of the bike baffles me however. I know the NT is not a powerhouse, but it is quite happy and comfortable cruising on the Interstates at 80-90 mph! How fast do you want to go? There are many of us who have over 100K miles on our NT's and have traveled to all of the lower 48, Canadian provinces and Alaska and if that's not "true touring" I don't know what is. If your riding style dictates keeping the bike at 5K rpm that's perfectly Ok and it won't hurt it a bit. Hondas like to rev. But I think you would find it a lot more relaxing to ride with the engine at a lower rev count. Unless I'm in hilly country, putting along at anything over 3K rpm is delightfully smooth and quiet.

Mike

hey all mil light was still on after the self-check, so i didn’t start bike just put down the kickstand.

it’s flashing code 8, which is ‘throttle sensor voltage high or low’. this makes some sense, as the problem i’m experiencing is engine lags and surges while throttled (cruising).

any advice on what’s next? i’m fairly klutzy but at the same time haven’t been real lucky finding friendly honda motorsport dealers nearby ...

 

[toowired]

As others have said get the code, decode it to see where to look first.
There have been reported sensors that open (fail) with heat. That is a possibility with your symptom of 20 minute delay till surging.

Brad

yes, thanks to all the kind help here i’m fairly certain it’s an issue w the throttle sensor. can you advise next step(s)?

 

[Phil Tarman]

did you have the same 20 to 30 minutes of smooth operation before the engine light came on? did you have the same surging? i assume other than taking it to a dealer (which i’m willing to do if no easy fix), that there’s no way for me to know ‘what the engine light is telling me’?

I had 30-45 minutes before the stumbling ("stumbling" seems to fit better than "surging" to describe what I experienced) started. A couple of times, I had a hard time holding the 65-70 I was cruising at and once had made up my mind to turn around and come home, but then I pulled in the clutch and revved the engine and the stumbling cleared up. After riding nearly 160 miles, after I was back into town, the bike died three or four times when I would come to a red light and stop.

You also said: "the nt700 is a bit underpowered for divided highway use (imo), so i am seldom cruising at 60 or more. personally i love the bike, but i think the nt700 has no business on the interstates. i feel like an underpowered sitting duck."

I beg your pardon? On my "Epic Ride" (see www.ptarman1.com to read all about it), I rode I-8 and I-10 from San Diego to Lake City, FL. In eastern CA, AZ, NM, and west TX, if I had not cruised at 80-85, I would have been run over. Gas mileage dropped significantly at those speeds, but I was perfectly comfortable maintaining the speed that the rest of the traffic was keeping. To accelerate, I'd just drop down into 4th. 85mph in 5th is only 6020rpm and the bike will run at 7500rpm without any great difficulty.

I will concede that I haven't spent much time at speeds above 100 on the NT. But, so far, I haven't needed to do that. Back in '08, I rode for three weeks in Europe on a Kawasaki GTR (the European name for the Concours). It was an '89 model and would get on the positive side of 120mph pretty easily, but in probably 3500 miles on Autobahns and similar high speed roads in Switzerland, Austria, and France, I mostly used speeds between 85-95. The NT would have been just fine at those speeds.

I agree that on twisty 2-lanes, I rarely get into 4th or 5th gears. 2nd and 3rd work very well for most of those roads.

 

[Phil Tarman]

yes, thanks to all the kind help here i’m fairly certain it’s an issue w the throttle sensor. can you advise next step(s)?

My MIL (engine light) was also showing 8 short flashes, the same as yours. There was nothing wrong with the throttle sensor ("TPI" stands for Throttle Position Indicator). There is a connection that a tech had disconnected when doing work on the bike. Either the connection was dirty or the connector was broken -- I don't know which, but the tech who had done most of the work and didn't realize that connector had had been disconnected, fixed it once he saw the 8 flashes.

 

[toowired]

I had 30-45 minutes before the stumbling ("stumbling" seems to fit better than "surging" to describe what I experienced) started. A couple of times, I had a hard time holding the 65-70 I was cruising at and once had made up my mind to turn around and come home, but then I pulled in the clutch and revved the engine and the stumbling cleared up. After riding nearly 160 miles, after I was back into town, the bike died three or four times when I would come to a red light and stop.

You also said: "the nt700 is a bit underpowered for divided highway use (imo), so i am seldom cruising at 60 or more. personally i love the bike, but i think the nt700 has no business on the interstates. i feel like an underpowered sitting duck."

I beg your pardon? On my "Epic Ride" (see www.ptarman1.com to read all about it), I rode I-8 and I-10 from San Diego to Lake City, FL. In eastern CA, AZ, NM, and west TX, if I had not cruised at 80-85, I would have been run over. Gas mileage dropped significantly at those speeds, but I was perfectly comfortable maintaining the speed that the rest of the traffic was keeping. To accelerate, I'd just drop down into 4th. 85mph in 5th is only 6020rpm and the bike will run at 7500rpm without any great difficulty.

I will concede that I haven't spent much time at speeds above 100 on the NT. But, so far, I haven't needed to do that. Back in '08, I rode for three weeks in Europe on a Kawasaki GTR (the European name for the Concours). It was an '89 model and would get on the positive side of 120mph pretty easily, but in probably 3500 miles on Autobahns and similar high speed roads in Switzerland, Austria, and France, I mostly used speeds between 85-95. The NT would have been just fine at those speeds.

I agree that on twisty 2-lanes, I rarely get into 4th or 5th gears. 2nd and 3rd work very well for most of those roads.

so did the problem just clear up for you? someone indicated it could be heat related, should i trace the throttle cable and make sure it’s not resting on or near a heat source?

and ok, you madman. i like to cruise at higher rpm. but over 6k for extended distances? can we agree that’s hardly ‘smooth and powerful’? seems like a turbo 4 vs a v-8 to me do you ever get out to eastern pa? i’d be down to meet up and trail you on an interstate cruise. so long as you’re ok w slumming at 70 to 75 mph? and no crazy crosswinds, please

OOPS, sorry. hadn’t seen reply above. do you think i could check this connection myself? do you know how to get to it? maybe be able to post a pic or two? no one’s been working on mine, but maybe it worked loose? and due to fact bike runs fine first half hour, i do think i should check path of throttle cable.

 

[Phil Tarman]

I have no idea why four posts showed up without me putting any content in them. Of course, lots of things baffle us old men.

 

[NewTo700V]

hey all mil light was still on after the self-check, so i didn’t start bike just put down the kickstand.

it’s flashing code 8, which is ‘throttle sensor voltage high or low’. this makes some sense, as the problem i’m experiencing is engine lags and surges while throttled (cruising).

any advice on what’s next? i’m fairly klutzy but at the same time haven’t been real lucky finding friendly honda motorsport dealers nearby ...

My very first post back in June was about clearing up this exact same issue. I too had MIL code 8 and engine surging. Read here:. https://www.nt-owners.org/forums/threads/throttle-position-sensor-tps-part-number.10192/post-165851

I also just read "stay in 1st or 2nd".. You do what now? Second gear will get me out of the 25 mph zone in the neighborhood. After that I'm in fourth gear up to about 50. At 50 I'm in fifth gear unless I need to downshift for a pass or climbing a mountain grade. I wonder if your riding style is just baking the throttle body subharness. It is routed below the throttle body between the "V". I definitely wouldn't be taking the high revs - low speed approach in summer. 3rd gear doing 50?! Unless you need to do an emergency pass or climbing a real steep grade, the NT can sit comfortably at 5th when you hit 50.

Honda's official shift recommendations can be found on page 60 of the owner's manual. I find their shift points a little too low, but you're nowhere in the ballpark sitting at 50 in 3rd gear for normal cruising.

"Recommended Shift Points
Ride in the highest gear that lets the engine run and accelerate smoothly. This will give you good fuel economy and effective emissions control. When changing gears under normal conditions, use these recommended shift points:
From 1st to 2nd: 12 mph (20 km/h)
From 2nd to 3rd: 19 mph (30 km/h)
From 3rd to 4th: 25 mph (40 km/h)
From 4th to 5th: 31 mph (50 km/h)"

 

[Phil Tarman]

NewTo700V, you might try using 3rd if you're in an area with curves...50mph in 3rd is 5,000rpm and power is much more responsive than in 5th.

 

[toowired]

My very first post back in June was about clearing up this exact same issue. I too had MIL code 8 and engine surging. Read here:. https://www.nt-owners.org/forums/threads/throttle-position-sensor-tps-part-number.10192/post-165851

I also just read "stay in 1st or 2nd".. You do what now? Second gear will get me out of the 25 mph zone in the neighborhood. After that I'm in fourth gear up to about 50. At 50 I'm in fifth gear unless I need to downshift for a pass or climbing a mountain grade.

hey there’s more than one way to skin a cat ... i’m pretty firmly in the high rpm for upshift and cruising camp. i totally respect where you’re coming from and i’m sure it’s a smoother, quieter ride. i’m also a bit timid and i like the natural braking effect throttling back from higher rpm provides. i’ve crashed in an ultralight aircraft (flying go-cart) and been hit by a car on a bike. a huge goal of mine is no more crashes or injuries

but it sure sounds like you have the solution to my engine woes! it sounds like something i could actually handle, provided i can find those 3 connectors. do you have any idea where i could find detailed instructions? could you possibly post some pics? is there a lot of stuff that needs removing to get to said connectors?

i’m the dangerous combination of cheap but not mechanically skilled. i think if i approach this carefully i might be able to pull it off without causing costly damage. no guarantees of course, but what do you think? i’ve yanked and installed computer components over the years. sounds roughly similar ...

 

[NewTo700V]

NewTo700V, you might try using 3rd if you're in an area with curves...50mph in 3rd is 5,000rpm and power is much more responsive than in 5th.

I'm usually climbing a very twisty mountain grade if I'm dropping to 3rd at that speed. But for just curvy roads on relatively flat areas, I can't say I need to do that. I'm pretty decent about carrying through maintaining speed in curves, so there's not usually a lot of acceleration going on.

 

[toowired]

My very first post back in June was about clearing up this exact same issue. I too had MIL code 8 and engine surging. Read here:. https://www.nt-owners.org/forums/threads/throttle-position-sensor-tps-part-number.10192/post-165851

I also just read "stay in 1st or 2nd".. You do what now? Second gear will get me out of the 25 mph zone in the neighborhood. After that I'm in fourth gear up to about 50. At 50 I'm in fifth gear unless I need to downshift for a pass or climbing a mountain grade. I wonder if your riding style is just baking the throttle body subharness. It is routed below the throttle body between the "V". I definitely wouldn't be taking the high revs - low speed approach in summer. 3rd gear doing 50?! Unless you need to do an emergency pass or climbing a real steep grade, the NT can sit comfortably at 5th when you hit 50.

Honda's official shift recommendations can be found on page 60 of the owner's manual. I find their shift points a little too low, but you're nowhere in the ballpark sitting at 50 in 3rd gear for normal cruising.

"Recommended Shift Points
Ride in the highest gear that lets the engine run and accelerate smoothly. This will give you good fuel economy and effective emissions control. When changing gears under normal conditions, use these recommended shift points:
From 1st to 2nd: 12 mph (20 km/h)
From 2nd to 3rd: 19 mph (30 km/h)
From 3rd to 4th: 25 mph (40 km/h)
From 4th to 5th: 31 mph (50 km/h)"

yeah, i don’t shift into 2nd til about 29 mph. i stay in 2nd til 40 or so. 3rd for 45 to maybe 60, if i’m only gonna be doing 60 short term. rarely go past 3rd gear. but i haven’t been able to hit true highway lately due to issue at hand. obviously for extended highway i’d be at least 4th. i downshift back to 1st just below 30 mph as well.

try it sometime! see how the ‘other half’ lives. like i also mentioned, i’ve got a spyder and that forum extols the zen of high rpm quite doggedly. i very much believe dipping too low in various gears is not good for the engine over time.

i said it earlier, i believe (from what i’ve read) that using higher rpms is very common in europe. no idea why. it all feels pretty ‘foreign’ at first (see what i did there?). i have to say once you’re used to it it becomes quite natural. i will admit if i have a passenger i may lower my rpm goals a bit

i think the bike is quicker to respond both accelerating and decelerating at higher cruise rpm. i’m no stunt rider, i like sloshy smooth sedan-y automobiles.

however i just saw the portion of your reply referencing that my higher rpms could be increasing the heat and causing my problem. and <that> is a valid point! next time i ride i’ll try the much smoother approach. will be interesting to see.

 

[NewTo700V]

The heat probably isn't helping the issue, but it's still most likely a connector needs some cleaning. It's not like you're boiling out coolant, so I don't think there's wires melting anywhere.