I bought a 96 Ninja 250 used, good bike, did all the PM stuff on it, however even after adjusting the chain with the rear tensioners on the side kick stand to 1 inch plus or minus of play, the chain is still bouncing when riding...anywhere from 10 to 40mph, i can hear it hitting as im cruising down a flat paved road....i can see it too...

rear sprocket looks good, chain has been cleaned and lubed plenty with chain wax.....i actually bought a JT kit with a 15/41 off ebay, that will be installed next week and i'm hoping this is the issue as i can't tell if the chain is worn or not....seems to be the original as i cant find a master link....

is bouncing a sympton of a worn chain? I'm new to bikes and rapidly learning off ninja250.org and this site as well, thanks for the advice all...

PS - i can post pics if needed...

roll the rear wheel and check the tension on the chain. it could be unevenly worn.
maybe you'll find at certain positions, it has much more slack

Welcome Nick!

A learning opportunity for us both. What’s the rationale for adjusting chain tension while on the side stand? I didn’t read the book when I replaced (and later adjusted) my chain, but it would seem easier to adjust and check for wheel alignment while on the center stand.

You didn’t mention how many miles are on the bike. Could it be that your chain is stretched enough so that could be long enough that it can bounce on the swing arm?

If you get a new chain, you might want to inspect the front and rear sprockets. My opinion is that you could probably get away with changing only the front sprocket, as it sees about 3 times the load and wear compared to the rear sprocket. A standard “520” o-ring or x-ring chain is a fairly easy to make the correct length with a chain breaking tool from Harbor Freight of Cycle Gear. And sprocket changes are no big deal, either. Also a good time to consider larger or smaller front and rear sprockets.

And congrats on the bike!

.........is bouncing a sympton of a worn chain?...

Welcome to our site, Nick !!!

No, it is a sign of excessive slack.

Put her on the central stand and hang 20 lbs from the chain at different points and measure 20 links of the chain.

You will need to replace the chain is you are replacing sprockets anyway.

http://www.ninjette.org/forums/attachment.php?attachmentid=22307&d=1355929145

A learning opportunity for us both. What’s the rationale for adjusting chain tension while on the side stand? I didn’t read the book when I replaced (and later adjusted) my chain, but it would seem easier to adjust and check for wheel alignment while on the center stand.

You didn’t mention how many miles are on the bike. Could it be that your chain is stretched enough so that could be long enough that it can bounce on the swing arm?

If you get a new chain, you might want to inspect the front and rear sprockets. My opinion is that you could probably get away with changing only the front sprocket, as it sees about 3 times the load and wear compared to the rear sprocket. A standard “520” o-ring or x-ring chain is a fairly easy to make the correct length with a chain breaking tool from Harbor Freight of Cycle Gear. And sprocket changes are no big deal, either. Also a good time to consider larger or smaller front and rear sprockets.

And congrats on the bike!


bike had 21k miles on it...i ordered a JT 15/41 kit....chain, front sprocket and rear sprocket.....

Welcome to our site, Nick !!!

No, it is a sign of excessive slack.



How is it a sign of excessive slack when I have 1 inch of play after I've adjusted the tensioners while the bike is on the kick stand (not the center stand) as the manual recommends?

How is it a sign of excessive slack when I have 1 inch of play after I've adjusted the tensioners while the bike is on the kick stand (not the center stand) as the manual recommends?

how many times did you measure the chain in different spots to confirm it wasn't stretched unevenly?

also who cares if you are getting new chain and everything. just put the new one on

How is it a sign of excessive slack when I have 1 inch of play after I've adjusted the tensioners while the bike is on the kick stand (not the center stand) as the manual recommends?

Because properly tensioned chains don't hit the swingarm: the slack practically disappears when you seat on the bike and both sprockets and the pivot of the swingarm get aligned.

It is important to find out the reason because if the chain is hitting now, the new one is going to hit harder with the sprocket of 41 teeth.

The recommended slack, while on the central stand and rear tire in the air, is 35~40 mm.
On the side stand, the suspension is compressed some under the weight of the bike, so the slack should be less.

If the rear suspension has been modified (lifted, lowered, harder shock absorber), then the recommended slack is not ideal.
The attached picture could help you verifying that.

I would also check if the plastic protector by the pivot of the swingarm is there.

The chain may be tightening / loosening at intervals. This can be caused by worn bushings or bearings where the swing arm pivots. The easiest way to check is put it on the center stand, remove the rear wheel. Try twisting the swing arm, then try to moving it lateraly. It should only move up and down on the pivot, and not move in any other direction.

I would also check if the plastic protector by the pivot of the swingarm is there.

What plastic protector are you referring too? Can you show me which one?

The chain may be tightening / loosening at intervals. This can be caused by worn bushings or bearings where the swing arm pivots. The easiest way to check is put it on the center stand, remove the rear wheel. Try twisting the swing arm, then try to moving it lateraly. It should only move up and down on the pivot, and not move in any other direction.

Center stand is gone due to muzzy exhaust, got the bike that way....

Center stand is gone due to muzzy exhaust, got the bike that way....

Sounds like you need to get a swing arm stand.

The chain may be tightening / loosening at intervals. This can be caused by worn bushings or bearings where the swing arm pivots. The easiest way to check is put it on the center stand, remove the rear wheel. Try twisting the swing arm, then try to moving it lateraly. It should only move up and down on the pivot, and not move in any other direction.

I'll try this when the new chain and sprockets come in.....

The chain bounces while the bike is still in 1st gear coming out of my driveway....do you think the swingarm could still be the culprit in that case?

The recommended slack, while on the central stand and rear tire in the air, is 35~40 mm.
On the side stand, the suspension is compressed some under the weight of the bike, so the slack should be less.

The attached picture could help you verifying that.

I would also check if the plastic protector by the pivot of the swingarm is there.


Couple of things...

1. factory manual says to check the chain on the side stand, should be 35-45MM. it doesnt mention center stand and i dont have one so that idea is out,, however i can use a jack and jack stands on the swing arms to support it which is what i did when i changed the rear tire.

2. The pic is weird....my rear caliper and disc is on the right side, your pic is on the left....is that like a Jap model or something?

3. Seems there is a black piece of plastic behind the tensioner in the pic, i dont have one of those...maybe due to a different model in the pic?

http://faq.ninja250.org/wiki/How_do_I_measure_chain_slack%3F

http://faq.ninja250.org/wiki/How_do_I_measure_chain_slack%3F

Yea ive thru that site like crazy learning about this stuff...

One thing I read about is being able to pull the chain away from the sprocket indicates its time for a new one....i just went out the garage, bike is on the side stand, slack is still one inch, so thats ok...however i was able to pull the chain off the rear sprocket at this point in the picture about 1/4 inch or so....it shouldnt move at all, correct?

One thing I read about is being able to pull the chain away from the sprocket indicates its time for a new one....i just went out the garage, bike is on the side stand, slack is still one inch, so thats ok...however i was able to pull the chain off the rear sprocket at this point in the picture about 1/4 inch or so....it shouldnt move at all, correct?

Look at the teeth on the sprocket they have little groves at the top once they are gone you need to replace it.

What plastic protector are you referring too? Can you show me which one?

Indeed; it is part 55020.

http://images.cmsnl.com/img/partslists/kawasaki-1987-ex250-e2-ninja-250r-swing-arm_mediumkar033455094_f2e4.jpg

Couple of things...

1. factory manual says to check the chain on the side stand, should be 35-45MM. it doesnt mention center stand and i dont have one so that idea is out,, however i can use a jack and jack stands on the swing arms to support it which is what i did when i changed the rear tire.

2. The pic is weird....my rear caliper and disc is on the right side, your pic is on the left....is that like a Jap model or something?

3. Seems there is a black piece of plastic behind the tensioner in the pic, i dont have one of those...maybe due to a different model in the pic?

1) We have different factory manuals. Do you see logic on hanging 20 lb (as directed in my manual, which picture I have attached previously) from a chain that is not on a vertical plane?
You should give a little less slack if the swingarm is supporting the weight of the bike, either on the side stand or on a jack stand (the shock absorber is compressed some and the geometry is closer to the sprockets-pivot alignment explained earlier).

2) Good eyes !!! The picture is inverted but still belongs to a Ninja 2007 like yours.

3) Sorry, I don't see that black piece of plastic behind the tensioner in the pic. Again, it is a 2007 model and dimensions are there to help you determine if the geometry of your rear suspension is stock.

You can find more information about chains here:
http://www.dansmc.com/rearchain.htm

Look at the teeth on the sprocket they have little groves at the top once they are gone you need to replace it.

i checked the sprocket.....smooth as a babys bottom....guess its good i ordered a new JT set....

i checked the sprocket.....smooth as a babys bottom....guess its good i ordered a new JT set....

How much did all that cost you? I'm looking into a new chain as well. Thanks!

How much did all that cost you? I'm looking into a new chain as well. Thanks!

ebay....$96 w/free shipping...just search up JT 15/41

more pics...i tightened up the chain alot, went down the street, still bouncing so i ripped the MF'er off....it was the original chain @ 24,000 miles....i used a circular saw and a metal blade....no problems at all, pics attached....

those look horrible

those look horrible

Yes! Ready to become "throwing stars" in their next phase of life.

Yes! Ready to become "throwing stars" in their next phase of life.

well im glad people with more experience than me agree, hopefully this will solve my issue once the new parts are installed so i can get back to riding.

more pics...i tightened up the chain alot, went down the street, still bouncing so i ripped the MF'er off....it was the original chain @ 24,000 miles....i used a circular saw and a metal blade....no problems at all, pics attached....

I think something is seriously wrong with my setup because I've been through a few sets and my front sprockets always looked new while my back sprockets were well on their way to looking like your front. The space worn between teeth allows the rollers some room to move between teeth. This is where most of the slack comes from when you pull the chain from the rear sprocket to see how much tooth is exposed. The thing is, my chains would start rattling and requiring constant adjustment because it was wearing the sprockets extremely fast. The first chain had a kinked master link but the others I couldn't explain. The rollers kept cracking and coming off, causing the sprocket teeth to rest on the pin that holds the chain together or on a the C-shaped remnants of a roller. It's not hard to see how that would accelerate sprocket wear, but I still don't understand why it happened to two new chain and sprocket sets in a row or why my front still looked new while my rear was totally chewed up.

Old video I made:
vhCFiuOs8E4

Just throwing this in the mix....I had alot of chain issues couple months back. Stretch like crazy. First off it was a cheap chain. Second it was old. Thirdly.......check your engine mountsà specifically the very bottom one. The nut came loose on mine and the bolt walked its way out allowing the engine to rotate forward and backwards with every accel and decell. Loose engine=chain slack/tighten.