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Discussion Starter · #1 · (Edited)
Today I "adjusted" the chain all by myself, as opposed to the other times when I had it done by the dealer or have my brother help me out. I hate the chain adjustment because I don't feel I can be precise enough when measuring the slack.

I took more than an hour to do it. I tried doing it by the book: have the bike on the side stand while measuring and adjusting and I tried to find that spot that it tightest (not sure that I succeeded). I use a cheap plastic vernier caliper to measure the slack, it is precise enough for the job.

Long story short, after I finished, I took a short ride but I felt a strong grating vibration regularly, like maybe every turn of the chain. Because it wasn't there before, it obviously has something to do with my adjustment. So, I looked at the bike and the right side wheel alignment indicator was not really in the same spot as on the left side. When I loosened the axle nut, the indicator "cover" was moving so when I had finished my adjustment it looked OK to me. But not after the ride.

I loosened the nut again and tried to re-allign the rear wheel. Now, I still feel the vibration but it seems less intense. I feel it through the foot pegs and mostly when the clutch it not engaged so no engine vibrations go through the transmission.

Tomorrow I will put the bike on the rear stand and try to see if I can locate the source of the friction. Right now, my hypothesis is that the wheel is not alligned properly. But it could also be the chain that may be a bit too tight in spite of my attempts to have it according to specs. I don't know if this could be similar to what Matt describes in the chain thumping noise thread.

I suspect that this a beginner's mistake and so, has this happened to anyone else? If yes, how did you fix it?

Second, is there an easy way to precisely align the rear wheel?
 

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Discussion Starter · #2 ·
I will get one of the tools advised here: After my chain slack adjustment.. Meanwhile, I wonder if it is safe to ride. Anyway, still looking for answers to the questions above. I have an 18000km maintenance scheduled by the dealer at the beginning of October but I would like to fix this by myself, before that.
 

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I would always recommend adjusting chain while the bike is on a rear stand. Makes things easier. I'm sure the manual tells you how to do it on the side stand because they assume most owners don't have a rear stand, but if you do, that's always the best and easiest way to do it. They say 20-30 mm of slack (measured from lowest to highest point, in the middle of the chain)...I tend to be on the upper side of that range. As far as aligning, I've never had any problems using the marks on the swing arm, so I just use those as a guideline. Some people have claimed they're not very accurate, mainly because those plates on the sides have a bit of slack in them. Doesn't really matter if they move a bit when you tighten the nut if you aligned them well before that. Although if you were adjusting just because of wear and tear (stretch) and not because you were putting in a different size sprocket, I'm guessing you only needed a bit of adjustment. Probably 1/4 of a turn on the nut on each side, and it should've been pretty good. It doesn't take too much.

After you adjust it and tighten everything back up, since you have a rear stand, you can also start it up, put in first gear, let out the clutch and let it spin on the stand. Look at the chain and see if it's making any weird noises. Then look from directly behind and see if the rear sprocket and chain appear to be misaligned.
 

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Discussion Starter · #4 ·
Thanks! I prefer to use the rear stand, makes things so much easier. So it's good to see someone who really know the bike, advising to do so.
 

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Even though the chain adjustment marks move around a bit, just push them both forward to make them even. They are accurate as I backed my measurements with an chain alignment tool and a tape measure. It's possible you might have the chain a bit tight.
 

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2019 Ninja 400 ABS, Pearl Storm Gray
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Another possibility is instead of using the adjustment marks, you can use an alignment tool like:


Make sure the rod points to the front sprocket.

The thing you want to be careful with here is not bending the rod.

To check the rod is straight, I spin it in its holder before using the tool and make sure the rod end stays in one point -- i.e., does not trace out a small circle because the rod is bent...

Tire Wheel Automotive tire Hood Vehicle
 

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Discussion Starter · #7 ·
Even though the chain adjustment marks move around a bit, just push them both forward to make them even. They are accurate as I backed my measurements with an chain alignment tool and a tape measure. It's possible you might have the chain a bit tight.
Problem fixed. That was it: the chain was too tight. I will never, EVER (well, unless I am on a road trip) adjust the chain on the side stand. It is difficult for me to judge which is the tightest spot. I used the rear stand and everything was OK.

I tried exactly this: have both marks in the same spot, the only thing is that the left one wasn't moving. I used the vernier caliper to make sure that the distance between the mark and the closest line was about the same on both sides.

One thing that I noticed on my bike, maybe it can help other beginners, is that once that I tighten the axle nut to specs, the chain tightens by 1 cm since last measurement. So I will keep that in mind. Thanks everybody, especially @sbk1198 for his advice to use the rear stand.
 

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Discussion Starter · #8 ·
Another possibility is instead of using the adjustment marks, you can use an alignment tool like:


Make sure the rod points to the front sprocket.

The thing you want to be careful with here is not bending the rod.

To check the rod is straight, I spin it in its holder before using the tool and make sure the rod end stays in one point -- i.e., does not trace out a small circle because the rod is bent...

View attachment 20245
This is one of the tools on my list, 2nd priority after the ECU flash (for my 02 sensor problem). :)
 

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yep, adjusting on rear stand is easiest! I do wish the Motion Pro alignment tool had a longer rod..like maybe double the length to really be sure everything is aligned. Another thing I've found helpful is to jam a rag between chain and sprocket before doing final tightening of rear axle nut. I've had things shift slightly when I don't jam the rag in.
 

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Discussion Starter · #10 ·
I used the rag (and the kick) to bring the wheel forward. Next time, I will use it as you suggest, before the final tightening as well. Thanks for the advice!
 

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Too tight is super bad. Watch the slow motion action of motorcycles while racing, and the slack in the chain will surprise you. If factory race bikes run that loose it should tell us it is not harmful.

IMO the alignment of the rear wheel is best done with strings or straight edges. Alignment of the wheels matters way more than the perceived alignment of the chain. If your bike is in good order, the sprockets will be aligned when the wheels are.
 

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Problem fixed. That was it: the chain was too tight. I will never, EVER (well, unless I am on a road trip) adjust the chain on the side stand. It is difficult for me to judge which is the tightest spot. I used the rear stand and everything was OK.

I tried exactly this: have both marks in the same spot, the only thing is that the left one wasn't moving. I used the vernier caliper to make sure that the distance between the mark and the closest line was about the same on both sides.

One thing that I noticed on my bike, maybe it can help other beginners, is that once that I tighten the axle nut to specs, the chain tightens by 1 cm since last measurement. So I will keep that in mind. Thanks everybody, especially @sbk1198 for his advice to use the rear stand.
The chain shouldn't get tighter when you tighten the axle nut, but it can happen if the whole thing moves backwards a bit, since there's nothing holding the wheel and axle in place besides a bit of friction before you torque down the nut. Some people shove a wrench in between the chain and the sprocket to prevent that from happening. I generally give the wheel a good push forward, I make sure both of the end plates on the swing arm are seated correctly and then I just jam my knee or lower leg into the back of the wheel to hold it in place while I torque the axle nut.
 

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Discussion Starter · #14 ·
Thanks! I loosened the axle nut enough so I could see a space. I was not sure how much friction it was providing. That's good advice though, to loosen it only a little. Will try next time.
 

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I always use a rear (Or center? 😁) stand, and always keep my chain on the "loose" side. Too tight chain can bend the counter shaft or tweak the seal, then yer screwed.
 

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Discussion Starter · #16 ·
The chain shouldn't get tighter when you tighten the axle nut, but it can happen if the whole thing moves backwards a bit, since there's nothing holding the wheel and axle in place besides a bit of friction before you torque down the nut. Some people shove a wrench in between the chain and the sprocket to prevent that from happening. I generally give the wheel a good push forward, I make sure both of the end plates on the swing arm are seated correctly and then I just jam my knee or lower leg into the back of the wheel to hold it in place while I torque the axle nut.
I was thinking about this and I prefer to leave the rag between the chain and sprocket, like @iahawk mentioned. Funny, I found an MC Garage video that advises the same thing: using a rag or a screwdriver to prevent the wheel from moving:
.
 

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I was thinking about this and I prefer to leave the rag between the chain and sprocket, like @iahawk mentioned. Funny, I found an MC Garage video that advises the same thing: using a rag or a screwdriver to prevent the wheel from moving:
.
I don't think a rag would work quite as well because it's soft so you could still get a bit of movement when you tighten the nut. I would use a wrench or screwdriver or some other hard object, but maybe if you bunch it up enough a rag would work too. I don't do either method now as mentioned above, but I have used the wrench method a few times in the past.
 

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As you tighten the axle nut you can tap the axle forward and keep the chain adjusting nuts under tension. I use a soft hammer.
 

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First things first. The chain slack. Get it to manufactures setting. If it says 30mm or whatever, push down on the chain, and with your tape measure, ( I use the small mm ruler), set it against the bottom of the swingarm, push down on the chain and look at the distance from the swingarm to the chain, pin, top of the chain, whatever area you chose. Then push up on the chain and see if that point moves the 30mm up the ruler. I know this is obvious, loosen or tighten the adjusters as needed. Once you now see that you’ve gotten the proper slack, this time push up on the chain, and see what the gap is to the bottom of the swingarm to the top of the chain. Now you don’t ever have to measure the travel of the chain again, you just set the distance to the swingarm every time. You can measure it if you’d like, but I can now tell just by looking at it while pushing it up. Easy and fast.

Chain alignment. If the chain is out of line with the sprocket, we all know it will wear the sprocket on one side or the other. The adjustment plates on these bikes are the worst I’ve ever seen. They move about a half inch depending how you push or pull on them. Super cheap! That being said, I just use them to get the chain in the approximate area for alignment. I never rely on them, even the good ones. Here's how you check the “actual” alignment. Get it where you think it should be and tighten the axel nut snugly. Don’t bother torqueing it yet. With the rear wheel on the stand, get behind the bike, a good light helps, and spin the wheel forward. When it stops moving take a close look at the gaps from the sprocket to the chain walls. If the chain is not centered with the same gaps on each side, you will need to move the axel. If the sprocket is up against the chain on the left side, loosen the nut and move the axel on the right reward slightly with the adjustor. If it’s going towards the right, move the left back. These adjustments should be slight. Retighten and spin the wheel again till you get it centered perfectly with the same clearance on each side. Check and see that it stays the same after you toque the nut.
 
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