Grinding noise - chain questions

[n4mwd]

I noticed an unfriendly sounding once per grinding noise apparently coming from my chain. It goes like "grunt . . . grunt . . . grunt" at regular intervals.

It can be heard when in gear and going slow - about 10 mph. Its easier heard when in higher gears and the engine is running very slow.

It cannot be heard when the clutch is pulled and I'm coasting.

The brakes have no effect on the sound or its interval.

It can also be felt and heard when taking off slowly from 2nd gear.

The interval of the grinding sound is affected by the speed of the bike and not the gear.

When I first heard the once per wheel rev grinding sound, I stopped because I thought there was something stuck to my rear tire. But there was nothing there. Both tires rotate easily and smoothly when off the ground.

Because it only grinds when the chain is under tension, I am thinking this is a chain issue.

So the questions are:

1. Has anyone else experienced this kind of noise before?

2. What, if any, are the symptoms of a damaged, ready to fail chain?

3. Have you lost a chain on the Ninja 250 pregen in motion and what happened? Did you lose control of the bike?

[choneofakind]

1. no I haven't. Sorry.

2. http://faq.ninja250.org/wiki/When_do...replacement%3F

3. http://faq.ninja250.org/wiki/File:Clip_link-1.jpg
I wouldn't want to be riding that bike when that chain let loose. Just saying.

[n4mwd]

Thanks, but that brings up a new question:

4. How do I know if my bike (stock) has an o-ring chain or not?

[planet-beaver]

Originally Posted by n4mwd

Thanks, but that brings up a new question:

4. How do I know if my bike (stock) has an o-ring chain or not?

You have oring chain.

[n4mwd]

Originally Posted by planet-beaver

You have oring chain.

Thanks. I've been searching the web since I wrote that and I think you are right.

I couldn't find anything specific on the web about the ninja, but I did find the attached photos which help tell the two kinds apart. The o-ring chain has a spacer that holds the side plates away from the link itself so the o-rings can fit in between the two. The standard chain doesn't. I found two photos on the web that show this. What's on my bike is clearly an o-ring chain like you said.

Now that I see how these things are made, I can see a clear flaw in that if the O-rings aren't lubricated, they will wear thin and let the dirt in and the grease out. Also, certain cleaners can cause rubber to decompose prematurely.

[choneofakind]

yes the ninja 250 definitely has an o-ring chain.

How many miles on your current chain?
What do the sprockets look like?
Have you noticed it getting slack excessively often lately?
Are there any kinks in it when it should be straight?
Can you pull the chain off the teeth of the sprocket by pulling one link straight towards the back of the bike?

[n4mwd]

Originally Posted by choneofakind

yes the ninja 250 definitely has an o-ring chain.

1) How many miles on your current chain?
2) What do the sprockets look like?
3) Have you noticed it getting slack excessively often lately?
4) Are there any kinks in it when it should be straight?
5) Can you pull the chain off the teeth of the sprocket by pulling one link straight towards the back of the bike?

1) I'm pretty sure its the original chain which would make it about 13K miles.

2) I only looked at the rear and the only thing I found that I didn't like was that the tips of the sprocket teeth were a little chewed and irregular. But the slot parts of it were normal.

3) No, but it was slack today. I tightened it and aligned the rear tire. It was 55mm and the specs call for it to be 35-45mm. Its about 40mm now. I test drove it this evening and I didn't hear any grinding noises. I'm going to try a longer ride tomorrow.

4) Its not especially kinky. Its flat where its supposed to be.

5) Nope.

I read online somewhere that I am supposed to clean and re-lube the chain after every ride in the rain. I haven't been doing that, so that may be my problem.

[n4mwd]

In searching the web for a solution to my problem, I came across this information regarding the motorcycle chain numbering system. I thought it was interesting so I thought I would post it here. There is also the ANSI chain numbering system, but motorcycles do it their own way.

A three digit motorcycle chain number such as #525 is deciphered as follows:

The first digit is the pitch or distance from one roller to the next measured center to center in eighths of an inch. So in this example, 5 corresponds to 5/8".

The roller diameter is also based off the first digit according to this table:
4 = 0.312"
5 = 0.400"
6 = 0.469"

The second and third numbers represent the roller length (not the diameter) times ten also in eighths of an inch. So in this example, the 25 corresponds to 2.5/8" or 5/16".

[choneofakind]

you *should* be ok. If the teeth on the sprocket make you uncomfortable at any time, then by all means replace parts. Just keep an eye on it. check the tension every couple hundred miles, and clean/lube it regularly and it should be good to go. If it starts needing tension adjustment every 100 miles, or gets kinked, or can be pulled off the back of the sprocket, it should be replaced.

[n4mwd]

Today I went for a longer ride and there was no grinding noise like there was before. I think tightening it must have fixed it - maybe.

[CZroe]

I kept thinking I fixed it and it kept coming back. Eventually, my sprockets needed to be replaced too.

[n4mwd]

Originally Posted by CZroe

I kept thinking I fixed it and it kept coming back. Eventually, my sprockets needed to be replaced too.

Did your chain make a grunting noise too?

Mine has been behaving itself recently since I tightened it.

[CZroe]

Originally Posted by n4mwd

Did your chain make a grunting noise too?

Mine has been behaving itself recently since I tightened it.

Yes. Low speeds.

[n4mwd]

Originally Posted by CZroe

Yes. Low speeds.

I'm going to keep my eyes on it. I already have a replacement chain. I'm going to buy the sprockets too because everyone says not to change just the chain.

[csmith12]

My pregen made the exact same sound your is. I would tighten and lube the sound would come back within a few hundred miles. Assuming everything else is in order, its time for a new chain.

Mine was also very pronounced at low speeds, but could hear it as higher speeds too.

[n4mwd]

I've been researching chains since I posted that and as far as I can tell, its rare for a chain to fail catastrophically except at the master link. Since this chain has no master link, I think I'm good that way.

I'm going to get some new sprockets for it and put the new chain on at that time. Everybody says old sprockets will ruin a new chain.

But it just seems like the original chain didn't do very well considering it an O-ring chain. I have been using Maxima chain wax lube on it since I got it. Its only got about 14K miles on it. It seems like it went kind of early. I'm starting to wonder if the chain wax is the wrong thing to use.