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Discussion Starter · #1 ·
Hello everyone,
Soon I’ll be coming up on the first chain replacement. Done 25k km on my current one so far. I was looking at swapping the sprockets with something more suitable for highway riding. I’m not too worried about losing some acceleration but I would like a somewhat lower rpm highway speed. Currently it’s 15 teeth up front and 41 teeth in the rear. What would be the ideal sprocket setup for this? Preferably still with silencer rubbers on them. Maybe someone has experience with different sprocket setups?

Thank you!
 

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You could consider a 16T up front. Let the rear be at 41T, and run the bike to see if this setup works for you. If not, you could drop a tooth or two at the rear too. I’ve been using a 16T up front and it’s perfect in dropping the RPM a bit to make for more enjoyable highway cruising. You may get error codes though because of the IMU which is not a problem on my ‘16 bike. The 16T impacts gear shifting positively too with each gear having a meaning unlike on the stock bike where 4 and 5 serve no purpose other than to get to the 6th gear!

With a 16T you won’t need to alter the chain length. You’d know that adding a tooth on the countershaft sprocket is equivalent to dropping 3-4 teeth at the rear.
 
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I was happy with a 16T front sprocket change. I don't know about getting them in India but 16T front sprockets with the rubber insert (my preference) are available. You can get aftermarket or OEM (for a different Kawasaki model).
Aftermarket JT sprocket:
OEM partnumber:
 

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A Black 2019 N1K
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It looks like you own a 2018 N1K, and I seem to recall that changing the sprocket (front, back or both) will most likely cause the ECU / TC to throw an error code.

Changing the sprockets was possible on all models on N1K up to an including 2016.
 

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True, I used the 16T sprocket on my '11 and '14 Ninjas. Haven't done the '18 yet waiting for a little more data.
 

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As of right now, I can confirm 39T works well for my 2018. No error code over many miles and under different conditions ,so I'm pretty sure the ECU will tolerate it. That's also with a 180/55 rear, which is slightly (4mm) taller than the stock 190/50, that also up the effective rear ratio just a hair.

I bought the 16T @kenors posted above and will be trying that soon. I expect it to work fine with the stock 41T rear sprocket put back on, but I won't know for certain until I actually do it.

Highly doubt the ECU will tolerate 16T/39T. Frankly, I'm not sure I'd want/like that much change in overall gearing ratio anyway.

If you want to raise the gear ratio, I would suggest trying the 39T rear first. Cost difference vs. a new 16T is minimal. The stock 15T front sprocket is a b!tch to remove the first time (from what I have heard). The rear sprocket swap is a piece of cake, especially if you do it at the same time you change rear tire. That's what I did, and the extra work was negligible.

The only advantage with 16T front is slightly longer service life with a larger sprocket. And a likely shorter wheelbase (vs. going with 39T rear), if you really want to get technical.
 
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Discussion Starter · #7 ·
Okey that sounds great. I think I’ll risk a 16t one because I already have the proper tools for this. If the ECU makes a problem I will just swap back to the 15t and try a 39 in the rear.
 

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I hate to pour negativity on this thread, but Murph is correct. Back in 2017 Motoman put a 16T front sprocket on his 2017 N1K, and it did throw a GPS (Gear Position Sensor) Fault after a 100 miles. Another user (Rummaggio) put one on his 2018, and his was initially fine for 500 miles. He put a set of 190/50 Road 5's on, and 100 miles later, his bike threw the error code as well.

GPS failure

If you have better luck, please let us know.


 

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I seem to recall, that after a lot of discussion about this matter over the years, that the "general" opinion was that you can go up 2 teeth on the back and "probably" not throw an error code, but going up 1 tooth on the front will throw an error code. ( 1 tooth front approx equal to 3 teeth back).

Some people have gone with a 190x55 tyre without error codes, but other people have had error codes. You are rolling the dice with this change.

Mix tyre and sprocket changes, and you are in no man's land.
 

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2019 Ninja 1000 ABS w/ Akrapovic Slip Ons.
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Hmmm. Today I put a 16T front, and 40T rear on my 2019 Ninja 1000. Just went for a short 30 mile ride after the work was done. Found myself actually using 4th and 5th gear…not just skipping to 6th. Well I will let you know when I get a trouble code…I hope I don’t..but sounds like I will.
 

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I seem to recall, that after a lot of discussion about this matter over the years, that the "general" opinion was that you can go up 2 teeth on the back and "probably" not throw an error code, but going up 1 tooth on the front will throw an error code. ( 1 tooth front approx equal to 3 teeth back).

Some people have gone with a 190x55 tyre without error codes, but other people have had error codes. You are rolling the dice with this change.

Mix tyre and sprocket changes, and you are in no man's land.
Went for a ride the other day with a friend that has moved from Hayabussa's to the Ninja - he was used to cruising the highway at like 2500 rpm so was like WTF when his 2018 Ninja was closer to 4k rpm - He changed the front sprocket by 1 tooth and started throwing TC errors - So he moved by 2 teeth and the back and has had no errors since and got his revs down and feels more comfortable cruising. I will probably do the same on my 2021 when I stop buying other **** :)
 

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2019 Ninja 1000 ABS w/ Akrapovic Slip Ons.
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My front sprocket cover just has a hole where the earlier models had a position sensor like used on the wheels for abs. I figured this was an earlier problem with bikes that had a sensor on the front sprocket nut and since I did not have this sensor that it would probably be fine. I read a lot of posts here last month before I ordered the sprockets…but did not see these posts. After going through all the work of breaking loose the front sprocket…I’m not in a hurry to undo it, but if throws a code I will.
 

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That's a good point because we don't really know if the front sprockets physical size was the issue, or the ratio?

Before I ever said any of these mods were ok, I would set the traction control to a beginner level and go spin my tire. See if you get the throttle body error code when you do. I'm not sure how/where you do this? Maybe find a wet, painted line? We have never had any explanation as to how the system works, on this specific bike. It's all been guesswork and trying to understand how and why those who had errors did.
 

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I was worried about clearance with the metal chain guide/retainer (not sure of name) that wraps around the inside of front sprocket housing And the chai….since the diameter of the sprocket is bigger. I pulled over and checked for any signs of contact several times early in the ride. Did not notice any, or notice any change in noise. I bought a steel Renthal 525 16T front sprocket. it does not have the rubber ring like the stock JT branded 15T sprocket. Not sure what the rubber ring is supposed to do. Does it soak up driveline slack? The rubber did have dimples where the links seemed to have previously pushed and worn on the rubber Slightly.

Ahh, spinning the rear tire on a bike like the opening of mad max is cool, but I am not sure that I am up for that.
 

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The rubber dampens the noise chain makes slapping around the small sprocket. The noise is not particularly loud, but any sound is generated by shock & vibration. I doubt the amplitude is severe enough to be detrimental, but it's there nevertheless.
 
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I also used a larger front sprocket without the rubber ring. The vibes were noticeable but not bad. I changed again to the same larger size front sprocket with the rubber insert and the vibration is now nearly undectable.
 

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BTW, on any motorcycle with traction control, the algorithm is running as long as the TC is enabled. That is, just like the ABS control loop, TC is comparing F&R wheel speeds continuously while the bike is moving. TC and ABS controllers have absolutely no clue what sprockets, tires sizes and pressure the bike is running, all of which affect what the F&R wheel speed differential is at any given time. All these systems know is what they were preprogrammed to expect. Kawi factory engineers set an acceptable range that, when exceeded, will trigger a fault.

As an example, I had a puncture on my Trophy SE once. The TPMS warning came ON first, and as the rear tire pressure continued to drop, a few mile down the road, rear tire's rolling diameter dropped to a point beyond that preprogrammed acceptable range, so the TC light came ON on the dash. Made sense and no surprise.

In any case, That factory-set tolerance range is necessary to account for variances in different mfrs' tire sizing (even if all 190/50) and prevailing environmental conditions. Some of us simply are cheating the system a little by taking advantage of that tolerance.

It doesn't matter what combination influenced the effective ratio between engine RPM to rear wheel speed, be it sprocket size, tire size, pressure, temp etc. If the combined effect exceed the preprogrammed tolerance, TC fault will trigger. Say, your '19 N1k with 190/55 and 40T could have been running without fault for 100's of miles back and forth to work. Then you decided to make a weekend run out of town. On the boring straight fwy with no traffic, you let her rip and run up into the triple digits. The high speed balloons the tire and increases the effective rolling diameter... (if the combined gear ratio was already very near the fault trigger threshold) BOOM! TC fault.

Of course, none of us know exactly where that numerical threshold is. Still, if you understand what feedback variables the TC control loop is monitoring and the parameters that affect those variables, there is no voodoo magic to any of this.
 
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That's a good explanation, Volfy. The very basic systems only cares about wheel speed. They also monitored the rate of rpm increase. How it would increase, faster, if you had a spinning tire. That's a dumb way of saying it, but , that's all I've got, today.

It would be a complete explanation if cornering abs wasn't factored into the equation. Once the added the imu, in 2017, now there are formulas concerned with the wheel speed relationships as the bike is leaned over. It's involved in the abs system, too.

As the bike leans, the bike is on the sides of the tire. It's as if the tires get smaller.. That would be easy to graph, but probably agravated by the 190/55 reat tire more so than gearing. Like you said, no one knows what the tolerances on these are.

Notice the date on this article, and how it mentions Kawasaki's patent. It was concerned with much more than wheel speed, dating back to 2011.


You are still correct, though, but with this all being monitored, I'm not sure how wise it would be to think this system is as safe as it should be once someone starts changing tire size, gearing, and maybe even higher quality tires.
 

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That article you linked describes race TC/ABS systems that are far removed from the typical road bikes. Just this sentence should've clued you in on that:

"Using Dunlop’s data for the tires used on the XR, a new slip signal can be generated, which is much more accurate. We have used the GPS signal here to determine slip (and GPS is certainly used in some advanced systems) as opposed to front wheel speed, but the concept is the same. This method is used in the BMW S 1000 RR traction control system."

Yeah, Kawi could've programmed street N1k with precise tire data from Bridgestone for the OEM S21/S22. What good would that do when the rider switches to another brand on the next tire change? And I can just about guarantee you there is not a GPS integrated with the Bosch IMU inside the '17+ N1k. Would be nice... but no.

Racing TC/ABS systems allow for many more parameter input than typical road bike systems, including the race track topology so the GPS can fine-tune the TC/ABS system from corner to corner.

Ours are far more rudimentary. There is a reason why a lot of moto-journals describe it as "cornering ABS", because that is no far from the extend of the lean angle data adds to the bike's dynamic control. With that, ABS controller estimate how much less braking traction is available at any given lean angle, and modifies ABS action accordingly. My guess is TC probably also takes lean angle into account when computing tire slip. Afterall, effective rolling diameter reduces as the tire leans onto its shoulders. However, because they have to account for a wide variety of aftermarket tire, all with different profiles, they would've left a sizable latitude in the lean angle compensation algorithm.

You're right RC that we do need to be careful when playing into the margins, as the street TC/ABS can be unsafe if we exceed the tolerances. So... how do we know when that is the case? Well... when the TC Fault warning comes on.
 

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Rode 70 miles today on the 16T / 40T (+1/-1) sprockets and stock tire sizes (190/50 17 Bridgestone S20) on my ’19 N1K...so about 100 miles so far. I hope it works, I like the reduced vibrations and less eager feel of the bike cruising in 6th. To me the other gears feel more usable now at slower touring speeds. I had traction control kick in while accelerating over a bridge expansion joint. It felt normal. Rear abs kicked In twice, once going over a stick with the rear brake on, the other when I unloaded the rear tire quickly with the brake. They felt like normal abs events.

I read up on traction control and ABS in the service manual this morning. It definitely says tire size changes will cause ABS and KIBS lights to trigger. Also read up on GPS faults (Gear Position Sensor…did not find anything about triggered by mismatch of engine revs to wheel speed…but that is not to say it is not missed in the service manual. What were the fault code numbers that people got with their GPS faults? Sounds like if this change triggers a fault, it will be that one.
Either way…no faults yet.
 
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