Lugging below 2.5k revs

My engine lugs badly below 2.5k revs and in every gear, my bike's a DCT and in D mode it's very obvious and consistent, it feels almost like a misfire that travels through the bars and I wonder if this is part of the vibration problem that these bikes are known for. When the bike's in S mode it's very smooth.

Reyno said:

I wonder if this is part of the vibration problem that these bikes are known for.

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Huh?
I had no idea these bikes were known for vibrations problems...where did you get that information?
I'm coming off of the smoothest motorcycle on the planet (GL1800 six-cylinder) and this bike is very close at highway speeds of 60-72 mph...
<shrugs>...
Maybe the 750 isn't as well balanced?

ld_rider said:

I'm coming off of the smoothest motorcycle on the planet (GL1800 six-cylinder) and this bike is very close at highway speeds of 60-72 mph...
<shrugs>...

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+1. Same here. Smooth.
Put it in "S" mode and try, as well as the manual mode and try. I never ride in "D" because it does lag a bit, but not like what you are describing....

Let us know. Good luck!

At 2.5k rpm, the bike is lugging. My manual does that too. It runs best around 3-3750rpm in terms of smoothness and still having power left up top to accelerate out of the way of something.

2.5krpm is literally 1500 over idle. Give it some dang juice.

I would check chain, sprockets and the cush drive before moving on to other checks or dealer

I noticed a little improvement in engine smoothness after adjusting my valves. Maybe if the valves on one cylinder are more uniformly in spec than the other, it could cause vibration from one cylinder generating more power than the other.

What is traditionally thought of as lugging is what this engine is designed to do in low revs. It is not a problem on the NC700 engine. Notice it is pulling strongly and doesn't die when it feels like itis lugging.

ld_rider said:

Huh?
I had no idea these bikes were known for vibrations problems...where did you get that information?
I'm coming off of the smoothest motorcycle on the planet (GL1800 six-cylinder) and this bike is very close at highway speeds of 60-72 mph...
<shrugs>...
Maybe the 750 isn't as well balanced?

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I thought all twin engines were quite prone to vibrations not least the NC which I've read many threads about here and on the UK forum, also I thought the 750 had an extra balancer shaft for extra smoothness.

icing777 said:

+1. Same here. Smooth.
Put it in "S" mode and try, as well as the manual mode and try. I never ride in "D" because it does lag a bit, but not like what you are describing....

Let us know. Good luck!

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As stated when the bike's in S mode it's very smooth and I have no complaints.

kharli said:

I would check chain, sprockets and the cush drive before moving on to other checks or dealer

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It's a 700 mile bike that's just come back from the dealer for it's first service, apparently all's well, not that I trust this dealer because so far they are proving to be quite unreliable.

Lou Wambsganss said:

I noticed a little improvement in engine smoothness after adjusting my valves. Maybe if the valves on one cylinder are more uniformly in spec than the other, it could cause vibration from one cylinder generating more power than the other.

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Worth checking I suppose even though my bike's new, doesn't look too fiddly once the radiator's out the way. I'm starting to suspect it's more pronounced on DCT bikes and my use of the throttle because it's less linear than it would be on a manual because you can keep the throttle in a fixed position.

As was mentioned, make sure the chain is not too tight. As for valve adjustment, I wouldn't expect much impact on vibration unless they were severely out of spec. Also, I'd expect smoothness to improve with break in. I just test rode a new 700, and compared to my 14,000 mile bike, the new one did seem rather rough in the 2000-2500 RPM range.

Riding it at that RPM won't hurt anything. It was designed for that.

I have the same bike as you, I no longer use D mode in town as it changes up too early and the engine can tend to lug if you're just pottering around. Once out of town I then go into D mode. I don't suffer any vibes though.

Mine runs great at 2500 rpm in any gear. Don't know what's wrong with yours. I live in level Lower Alabama. Hardly any hills.

I stopped using D mode as soon as I discovered what you describe - not because it's wrong for the bike but just because I found it unpleasant. As others have already said, it's sweetest kept at 3000rpm and above - why wouldn't you, you'll still get massive miles per gallon anyway?!

Mine also has no problems at 2500k, even with an exhaust mod. The bike is built for running at crazy low rpms, and will chug along right off of idle. Definitely check your chain's tension. What would be described as lugging for other bikes is just normality for the NC.

Let's not forget that the OP has a 750. Comparisons to the 700's low RPM behavior may not be valid.

I have the manual version and my engine lugs in 6th gear if I am below 2500 rpm. When this happens I just downshift to 5th and it runs fine. My gas mileage is consistently north of 70 mpg so it doesn't seem to matter unless I'm going faster than 55 mph. Then I definitely shift into 6th.

mgmirabelli said:

I have the manual version and my engine lugs in 6th gear if I am below 2500 rpm. When this happens I just downshift to 5th and it runs fine. My gas mileage is consistently north of 70 mpg so it doesn't seem to matter unless I'm going faster than 55 mph. Then I definitely shift into 6th.

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Just out of curiosity, what is your impression of your NCX versus your Sportster, engine feel-wise?

So Sunday morning I get out of the house on the 700 with no where in particular to go. This thread was on my mind so picked out a mix of roads that got me out of the city with minimum of stops and onto roads I could ride 45-55 mph with no traffic to speak of. Nice rural near-city roads with cows, horses, barns, etc to putt putt through. I know this a 750 discussion and I ride a 700 so you can stop reading now if that is a bother.

2.200 RPM in 6th is about 45 mph. As long as the engine is not asked to climb a hill or accelerate very quickly it tolerates 1,800 to 2,200 very well and is actually smoother than 2,600-2,800 which is 50 to 55 mph. If I needed to pull up a grade or speed up quickly I downshifted to 4th as trying to accelerate from these low revs in 6th is lugging the engine and it lets me know it doesn't like it. I rode about 50 miles out and turned around for home and filled up at 102 miles. A nice mellow ride. The mileage was 86 mpg. I don't normally take it this slow and easy but it was a nice change of pace and it demonstrated to me the 700 does not lug below 2,500 unless the engine is asked to accelerate from low revs in 5th or 6th gear.

I ONLY use D mode. Ive got 7000 miles on the odometer. Most of them spent at 45-55 MPH around 2000-2200 RPM. This engine is different than a traditional motorcycle engine. It has been designed to run low, and have big torque very low.

Stop thinking this is a short stroke inline 4 motorcycle.

And thanks to that Characteristic 270 crank, you get simulated V-twin vibrations. As for your missfire, this may be why, their is 450 degree of crank rotation before another piston fires. Making it seem like a missfire to some.

What is odd is Honda put a second balance shaft in the 750 to smooth it out even more.

Maybe you do have a problem. Time to visit the dealer.

OriginalRocket said:

What is odd is Honda put a second balance shaft in the 750 to smooth it out even more.

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Once you get to a certain size piston you have no choice unless you want your fillings to vibrate out of your mouth. An example is 650cc pistons is about the upper limit for a single cylinder design wise. I read an engineering article about it years ago but don't remember the specifics well enough to repeat. With the increased piston size in the 750 and being a twin cylinder they were probably forced to go with the dual counter-balancers.

Just out of curiosity, did it have this problem before you put a super open air filter on it? And have you gotten some sort of fuel management system since you did that?