13 NTX - soft rev limiter?

[andrewdonald1]

Is there a soft rev limiter on the NTX?
It seems like once I hit around 7K or 7250 RPM it's hitting a soft rev limit until cut out at 8K.

[ChuckH]

Is there a soft rev limiter on the NTX?...

Yes,  It's called the Gear Shift Setting and is described on Pages 66 and 67 in your Owner's Manual.  I think the setting from the factory is 6500 RPM (for break-in).  You can adjust it up from there as desired.

[andrewdonald1]

Yes,  It's called the Gear Shift Setting and is described on Pages 66 and 67 in your Owner's Manual.  I think the setting from the factory is 6500 RPM (for break-in).  You can adjust it up from there as desired.

That's just the red shift light.
I am referring to an actual soft rev limiter that partially cuts ignition until you hit the hard rev limiter.

[biking sailor]

Mine did not have that as far as I could tell.  Would pull up to hitting the rev limiter, then stutter until you shift or back out of it.

[beetle]

The factory maps have a 'rev limit input gear' table that's set at 8000 RPM. The fuel rev limit is 8500 RPM and fuel turns back on when revs drop to 8400.

For the gear rev limit table, the ECU calculates what gear you're in using speed vs revs. Since the speedo ain't that accurate, there's a fair variation in when it activates. It's part of the traction control.

[andrewdonald1]

The factory maps have a 'rev limit input gear' table that's set at 8000 RPM. The fuel rev limit is 8500 RPM and fuel turns back on when revs drop to 8400.

For the gear rev limit table, the ECU calculates what gear you're in using speed vs revs. Since the speedo ain't that accurate, there's a fair variation in when it activates. It's part of the traction control.

Great information: but does that mean it is what it is?  Meaning its going to have in essence a soft rev limit just north of 7K rpm.

[andrewdonald1]

Ok, I took it for a little ride today and determined a little more.

If I slowly bring up the rpm's without full throttle (like first gear bringing up the speed slowly but constantly), the motor spools all the way up to 8K.
If I am hard on the throttle it starts missing around 7250 RPM.

So I am thinking its probably a partially clogged fuel filter.
Probably can't flow enough fuel at full wide open throttle.

Comments? 

Where is the fuel filter so that I can swap a new one in and try it out?
Assuming pull the fuel tank and its probably in the "v" just down below the fuel pump hosing?

[beetle]

I have no opinion regarding a clogged filter,  but FYI , the fuel filter is attached to the fuel pump assembly

[pauldaytona]

I think there is nothing wrong. Unless you do strange things the filter will be new.

What are you doing in the >7k range so often? I'm normally not there on public roads.

[andrewdonald1]

I think there is nothing wrong. Unless you do strange things the filter will be new.

From my experience this appears to be pointing towards a partially clogged fuel filter.

[Vasco DG]

From my experience this appears to be pointing towards a partially clogged fuel filter.

I'd be very surprised if this was the case but if you want to eliminate it as a possibility? Go ahead.

Pete

[andrewdonald1]

I'd be very surprised if this was the case but if you want to eliminate it as a possibility? Go ahead.

Pete

Pete:  If its not that, what could it be?  I am assuming that isn't normal behavior.  I don't remember it doing that over the last 3K miles that I've had it.  It only has 6300 miles on it now.

I am thinking dirt/sludge in the fuel at some point when I filled it up. 
Just enough to partially restrict the fuel flow enough at full RPM/full throttle, thru the fuel filter. 

[Wayne Orwig]

From my experience this appears to be pointing towards a partially clogged fuel filter.

Remember, the fuel pump passes the same amount of fuel through the filter at idle as it does at wide open throttle and high revs.

I would suspect something like vibration messing with a sidestand switch, relay contact or wiring connector, before a fuel filter.

[andrewdonald1]

Remember, the fuel pump passes the same amount of fuel through the filter at idle as it does at wide open throttle and high revs.

.

Wayne:   is there a fuel return line back to the tank?
Meaning is the fuel delivery system a LOOP?

[Wayne Orwig]

Wayne:   is there a fuel return line back to the tank?
Meaning is the fuel delivery system a LOOP?

Yes, it is a loop that flows the same amount of fuel at all times through the pump and filter. The only variable with throttle is the time the injector is open which results in a bit less flowing through the regulator. The return is all contained within the tank.

Your description of more throttle / vibration sure sounds electrical, like a relay or switch contact.
Maybe an ABS sensor is kick in the traction control. I'm not familiar with that system in the least.

[Vasco DG]

Is it a flat or roller Tappet engine?

Pete

[andrewdonald1]

Is it a flat or roller Tappet engine?

Pete

Roller.

[Vasco DG]

OK, good. When the flats start to go they cause all sorts of weird behaviour.

Pete

[andrewdonald1]

Yes, it is a loop that flows the same amount of fuel at all times through the pump and filter. The only variable with throttle is the time the injector is open which results in a bit less flowing through the regulator. The return is all contained within the tank.

Your description of more throttle / vibration sure sounds electrical, like a relay or switch contact.
Maybe an ABS sensor is kick in the traction control. I'm not familiar with that system in the least.

My gut feeling was saying fuel filter do to:
[1] part throttle bringing up the rpms smoothly thru 1st gear for example, she revs all the way to 8K as normal.
[2] full throttle she starts missing at about 7250 rpm.

To me, that rules out RPM/vibrations in [1] above.
The only other variable I can think of with my limited understanding of the bike yet (although plenty in other systems) is the rate of fuel feeding into the injectors in [2], a higher flow rate is being used.  

But once again, I've been doing this long enough to know that the more you know, the more you realize the less you know.

I don't remember it doing this a couple tanks ago, although right after I finished up the 6250 service including new spark plug boots/plugs, throttle body synch, etc I filled up the tank at a gas station I don't normally go to.  Usually I am a chevron guy (or top tier), I never had a problem.
This time, it was a Mom&Pop gas station but not lower tier like Arco or something..

So I can't put my finger on exactly the cause since I've got a few variables going on.  

Need more wisdom..  Thanks guys.
Andrew

[beetle]

My feeling is something other than the filter. The fuel pump keeps the system pressurized more than enough to keep fuel available for pretty much any situation.

Is this only happening in first gear?

I suspect something funky with the traction control, or at least an electrical/ECU function.

[pauldaytona]

isn't it that the tacho is damped and has a slow reaction, so you think it is 7k , while you are at 8k?

[beetle]

isn't it that the tacho is damped and has a slow reaction, so you think it is 7k , while you are at 8k?

yeah, I'm thinkin that too. The ECU reacts before the tacho catches up.

[andrewdonald1]

Is this only happening in first gear?

Any gear.

[Wayne Orwig]

Any gear.

Sixth?







 ~;

[Cage Free]

My gut feeling was saying fuel filter do to:
[1] part throttle bringing up the rpms smoothly thru 1st gear for example, she revs all the way to 8K as normal.
[2] full throttle she starts missing at about 7250 rpm.

To me, that rules out RPM/vibrations in [1] above.
The only other variable I can think of with my limited understanding of the bike yet (although plenty in other systems) is the rate of fuel feeding into the injectors in [2], a higher flow rate is being used.  

But once again, I've been doing this long enough to know that the more you know, the more you realize the less you know.

I don't remember it doing this a couple tanks ago, although right after I finished up the 6250 service including new spark plug boots/plugs, throttle body synch, etc I filled up the tank at a gas station I don't normally go to.  Usually I am a chevron guy (or top tier), I never had a problem.
This time, it was a Mom&Pop gas station but not lower tier like Arco or something..

So I can't put my finger on exactly the cause since I've got a few variables going on.  

Need more wisdom..  Thanks guys.
Andrew

Since its a 13 isn't it still under the factory warranty?  If so why screw with it?

[andrewdonald1]

Sixth?

Sorry still on vacation.

Sixth?  Don't know.. that' would be pretty fast.






 ~;

[andrewdonald1]

Since its a 13 isn't it still under the factory warranty?  If so why screw with it?

Because its a pain in the butt to take it up 75 miles to Seattle, then leave it, then figure out a way back home.
Then do the same thing all over again.

That's 300 miles of driving..

[Scott of the Sahara]

I would think bad gas well before fuel filter, I think the filter is good for 20,000 miles.

[andrewdonald1]

Went for a little 40 mile ride yesterday and put in some gasoline anti-freeze/water dispersant in the tank.

Better in 1st gear.

Almost gone in higher gears.

Went thru about 20% of the gas yesterday.
I think its pointing to bad gas.

I'll keep updating as I get thru this.

[andrewdonald1]

Ok, went for another ride today.

Not bad gas.

I've got new gas in it.

Seems to be more predominant in the lower gears and less in higher gears.
1st is the worst.  
In higher gears like 3rd or 4th, its much less noticeable - in fact it feels like about 7250 - 7500 it is the worst then slightly better than once 8K it cuts again out like it should.

Anyone have any more ideas?  Still think its the tach not reacting quick enough to the ECU?
If that was the case, wouldn't the red shift light come on at the same time?  
If I bring it up thru the missing range, once it does indeed hit 8K, the red shifter light kicks in.
It still feels the same after 8K, meaning it feels like the ECU is kicking out the spark plugs prematurely.

I just changed out the spark plugs, boots at the 6250 service interval, maybe I should take another look at those items.