Engine Grinding noise,cam chain?

[zzrguy]

Hello, I was out riding my bike and all the sudden I heard strange noises and lost power. Tore the engine apart and everything in the top end was fine. Bottom is fine my bike is shifting fine and will move forward slowly. Put it back together and it starts but has the loud sound again and im pretty sure its the cam chain loose. I took out the tensioner and reinstalled and still got the noise. On-top of this when i start my bike and im getting this noise if i try to rev it higher than 3k it will stall out. can it still be the tensioner?

[n4mwd]

Originally Posted by zzrguy

Hello, I was out riding my bike and all the sudden I heard strange noises and lost power. Tore the engine apart and everything in the top end was fine. Bottom is fine my bike is shifting fine and will move forward slowly. Put it back together and it starts but has the loud sound again and im pretty sure its the cam chain loose. I took out the tensioner and reinstalled and still got the noise. On-top of this when i start my bike and im getting this noise if i try to rev it higher than 3k it will stall out. can it still be the tensioner?

A video would be helpful.

[Apocolypze01]

The rattle can be caused by a loose clutch basket. As far as the stalling goes.... I have no idea.

You mean when you rev it up past 3k it returns back to and BELOW 1k rpm and stalls?

[n4mwd]

The clutch basket is pretty common, but in this case, i don't think that's it. He said it happened suddenly while he was riding. Unfortunately, he didn't say what the noise actually sounded like.

If the cam chain slips, the engine wont usually run at all. The spring cam tensioner actually works pretty good. There is a slider inside there that pushes against the chain. That could fail, but honestly, I've never heard of anyone claiming that it did. Since he's got it all apart, it wouldn't hurt to examine the chain and associated parts.

Hopefully he will post with more data soon.

[zzrguy]

anyone know what this sound is ? the engine turns and runs but as soon as i give it throttle it starts to die.

Link to original page on YouTube.

[zzrguy]

Link to original page on YouTube.

[Alex]

/merged with original thread

[DaBlue1]

Have you checked the compression of the cylinders yet? That may explain the lose of power. It also sounds as if the timing may be a little off now as well.

[n4mwd]

There are a lot of things that can make it do that.

You said you tore it apart. Did you check the valve clearances when you were in there?

Also, I just did my valves and I was reading about people who had bikes swallow up rocker arms. Did you check to make sure there are all 8 in there?

Checking compression will also tell you a lot.

Check the low voltage wires to the coils and make sure they haven't come loose. Also check the fuses.

I can't tell if the ZZr is a 2-2 or a 2-1 exhaust. If you have 2 mufflers, start it again and feel the two exhausts for significant differences in pressure. They should be identical, but if not, its a clue.

A lot of times when an engine suddenly starts acting up while you are going down the road the problem is electrical. The most obvious thing is a malfunctioning spark plug. Time to change those if you haven't already. Check to make sure the coils are working and that each plug is actually firing. If you are using champion plugs then that is your problem right there.

It really sounds like one cylinder is working and the other isn't. That's my guess. I would check the electrical first because its easier, but then it could also be a plugged carb. Do you have an inline filter? Not sure if they have ethanol in the gas up there, but here it causes all sorts of problems.

A clutch basket isn't causing your problems. I seriously don't think its a cam problem or it wouldn't run at all. The cam chain should be tight and you shouldn't be able to pull it away from the teeth. That isn't to say its good. If a rocker broke loose and got wound up in there, the cam chain could be damaged even though its still working.

[zzrguy]

Originally Posted by n4mwd

There are a lot of things that can make it do that.

You said you tore it apart. Did you check the valve clearances when you were in there?

Also, I just did my valves and I was reading about people who had bikes swallow up rocker arms. Did you check to make sure there are all 8 in there?

Checking compression will also tell you a lot.

Check the low voltage wires to the coils and make sure they haven't come loose. Also check the fuses.

I can't tell if the ZZr is a 2-2 or a 2-1 exhaust. If you have 2 mufflers, start it again and feel the two exhausts for significant differences in pressure. They should be identical, but if not, its a clue.

A lot of times when an engine suddenly starts acting up while you are going down the road the problem is electrical. The most obvious thing is a malfunctioning spark plug. Time to change those if you haven't already. Check to make sure the coils are working and that each plug is actually firing. If you are using champion plugs then that is your problem right there.

It really sounds like one cylinder is working and the other isn't. That's my guess. I would check the electrical first because its easier, but then it could also be a plugged carb. Do you have an inline filter? Not sure if they have ethanol in the gas up there, but here it causes all sorts of problems.

A clutch basket isn't causing your problems. I seriously don't think its a cam problem or it wouldn't run at all. The cam chain should be tight and you shouldn't be able to pull it away from the teeth. That isn't to say its good. If a rocker broke loose and got wound up in there, the cam chain could be damaged even though its still working.

second cylinder is running really low compression. i had the top end open though and nothing seemed wrong. pistons were fine nothing broken. I use NGK plugs and i already tried new ones. any other ideas? could it still be carbs if the compression is low?

[n4mwd]

Originally Posted by zzrguy

second cylinder is running really low compression. i had the top end open though and nothing seemed wrong. pistons were fine nothing broken. I use NGK plugs and i already tried new ones. any other ideas? could it still be carbs if the compression is low?

If the compression on #2 is that much lower then its valves are probably the problem. Carbs are not likely your primary problem. You need to open it up again and take a closer look at the valve system. The valves are pretty much the only thing that can affect compression. A piston with a hole in it could also, but you'd probably see a lot of oil on the #2 plug.

I suggest you rotate the engine several times and watch to see if the valves operate like they should. The cam chain failing is a possibility, but its pretty remote.

[greg737]

I watched the video you posted. It sounds like an EX-250 engine running on only one cylinder. They'll run on one cylinder, I've actually ridden around the block on one cylinder. On one cylinder the EX-250 engine sounds totally different than it normally does, it's really down on power, it bogs, it won't rev any higher than about 4,000.

Have you confirmed that both sparkplugs are firing, getting good spark? Hold each spark plug near a piece of metal (that you're not currently touching!) and crank the engine over to see if a spark jumps.

[zzrguy]

im almost sure its the valves, how do i tell if they are normal when im turning the motor by hand?

And my plugs are good i just put in new ones and the old ones were fine too and its not my carbs because i turned the screws and they are leaking good

And its not a hole in the piston because when i took the top end apart they looked nice and new

[n4mwd]

When you had it apart, were you able to get a look at the cylinder walls?

There are 3 reasons why a cylinder could have low compression:

1) The compression rings are not working like they should which could be either they are broken or the cylinder is gouged.

2) The valves are leaking, or opening at the wrong times.

3) You have a leaky head gasket.


The number of miles on the engine are helpful in figuring out which one.

Did you look to see if all 8 rocker arms are still in there? And working?

[zzrguy]

Originally Posted by n4mwd

When you had it apart, were you able to get a look at the cylinder walls?

There are 3 reasons why a cylinder could have low compression:

1) The compression rings are not working like they should which could be either they are broken or the cylinder is gouged.

2) The valves are leaking, or opening at the wrong times.

3) You have a leaky head gasket.


The number of miles on the engine are helpful in figuring out which one.

Did you look to see if all 8 rocker arms are still in there? And working?

the rings around the piston looked fine and the cylinder was fine.
i did a leak down and 80% in the exhaust valves, how do i fix this any help?

Only 15000km on the bike and yeah all 8 rocker arms are there and working

[n4mwd]

Originally Posted by zzrguy

the rings around the piston looked fine and the cylinder was fine.
i did a leak down and 80% in the exhaust valves, how do i fix this any help?

Only 15000km on the bike and yeah all 8 rocker arms are there and working

Is it possible something is jamming the exhaust valve open? A screw or wire or something that accidentally got sucked in.

But I can say that if you are sure the valves are adjusted properly and the rocker arms are working and present, its time to pull the cams and head and closely examine your valves and timing chain.

Timing chains don't usually break, they stretch. If its especially loose, it might have hopped a tooth. But the tensioner should have picked up the slack on an engine with only 9000 miles on it.

A kawi engine failing at only 9K miles is very rare. But having a radically lower compression in one cylinder says there is likely something wrong with the valves.

If I lived up there I'd come over and give you a hand, but instead, maybe check with a kawi dealer and see if they will let you talk to their mechanic to see if he's heard of anything specific to your bike. Maybe offer to buy him lunch at McDonalds.

Broken Kawi 250 engines are rare like diamonds, just not as valuable.

PS- In case you didn't already know this, there are two TDC marks on the flywheel on the left side of the bike. The left TDC cylinder is marked "1T" with a line through it so it looks like "1|T". And the right cylinder TDC is marked "2T" or "2|T". I think there is also a "1D" or something in there too, but ignore that one.

[zzrguy]

Originally Posted by n4mwd

Is it possible something is jamming the exhaust valve open? A screw or wire or something that accidentally got sucked in.

But I can say that if you are sure the valves are adjusted properly and the rocker arms are working and present, its time to pull the cams and head and closely examine your valves and timing chain.

Timing chains don't usually break, they stretch. If its especially loose, it might have hopped a tooth. But the tensioner should have picked up the slack on an engine with only 9000 miles on it.

A kawi engine failing at only 9K miles is very rare. But having a radically lower compression in one cylinder says there is likely something wrong with the valves.

If I lived up there I'd come over and give you a hand, but instead, maybe check with a kawi dealer and see if they will let you talk to their mechanic to see if he's heard of anything specific to your bike. Maybe offer to buy him lunch at McDonalds.

Broken Kawi 250 engines are rare like diamonds, just not as valuable.

PS- In case you didn't already know this, there are two TDC marks on the flywheel on the left side of the bike. The left TDC cylinder is marked "1T" with a line through it so it looks like "1|T". And the right cylinder TDC is marked "2T" or "2|T". I think there is also a "1D" or something in there too, but ignore that one.

I wished you lived closer. I know about the TDC marks thanks
As for the timing chain i thought i heard it slipping but i opened it back up and they were lined up perfect at 33 teeth like its suppose to be.

I dont see how anything coulda got stuck as this happened while i was riding how do you check to see inside the valves? Like i know how to take apart the whole engine im just not sure how you remove the valves or inspect them or anything like that.

[n4mwd]

Originally Posted by zzrguy

I wished you lived closer. I know about the TDC marks thanks
As for the timing chain i thought i heard it slipping but i opened it back up and they were lined up perfect at 33 teeth like its suppose to be.

I dont see how anything coulda got stuck as this happened while i was riding how do you check to see inside the valves? Like i know how to take apart the whole engine im just not sure how you remove the valves or inspect them or anything like that.

If your air cleaner was missing, then something could have been sucked in that way. Or if there was debris in the intake from prior maintenance.

I have a hard time thinking it has anything to do with the cams. If the cam chain was bad or maladjusted, it would affect both cylinders and not just one. Its pretty rare for an engine with only 9K miles on it to fail. Is there a chance that you let the engine run without oil? Or overheat?

I have never done anything more serious to my Ninja than a valve adjustment so I'm basing this on what I know about other engines. Typically, to get the valves out, you have to use a valve spring compression tool to squeeze the springs down and get the valve keepers out. These are little wedges at the top of the valve stem.

I've attached diagrams in case you don't already have them. The tool is two parts: a big C-clamp 57001-241 and the adapter 57001-1202. These are very expensive from kawi so I'd look around for other sources. You could probably weld one up from a standard C-clamp and a short piece of steel pipe.

But before you start, exactly what were the two compression measurements? Were they radically different? The normal compression for a Ninja 250 is 142-218 psi. If your values were in that range, then I wouldn't be too worried.

Also, before you mess with the valves too much, I would drop about a tablespoon of marvel mystery oil down the spark plug holes and recheck the compression. If your rings are bad, the compression will increase dramatically.

Here is what the manual says about low compression:

1. Gas leakage around the cylinder head - replace the damaged gasket and check the cylinder head for warp.
2. Condition of the valve seating.
3. Valve clearance - If a valve requires an unusually large adjustment to obtain proper clearance, the valve may bend, and not seat completely.
4. Piston/cylinder clearance, piston siezure.
5. Piston ring, piston ring groove.

Let me know what you find out.

[n4mwd]

Another guy told me that if the valves are not seating properly, you can tell by checking the valve clearances because the valve will have a wide gap at TDC. The normal valve wear process makes the valves get tighter not looser with mileage. Have you checked your valve clearances? With METRIC feelers?

[zzrguy]

if anyone was wondering i found out what it was!
The valves were perfect like an arrow but it was the tensioner lever. not the tensioner but the lever it sits on had snapped off and made the cam chain loose which was messing up the timing/ firing should have her up and running for winter.. lol :P
thanks for your help all!

[n4mwd]

Glad to hear you found it. Its pretty rare for a failure with that few miles, but I guess somebody has to be the exception.

Are you referring to part #13168?

Do you feel that this caused the low compression, or is it possible that you may have measured the compression wrong?

I know that some people have replaced the standard tensioner with bolts. However, I am against that as it can easily put too much stress on the rocker and break it.

[greg737]

Glad you tracked it down. Good catch.

Just knowing that this unusual tensioner failure can happen might help some people in the future.

Looking at your picture of the fracture sight it appears that part #13168 is cast from some really unimpressive metal, or is it dark colored plastic?

Although, it certainly would more helpful if you would post your pictures in the correct orientation. Or do you hang the bike by the rear wheel from the garage rafters when you work on it?

[zzrguy]

Yes it is part #13168?



well from what i was told the reason i would get bad compression is because the cam chain isnt holding anything in place alloying air to flow freely compression test should be good once its all fixed

i added a explanation for anyone who is curious or for the future

the pictures may look off because they are on the stand i built for my 250 in school :P its very cool ill post pics sometime

[n4mwd]

You're probably right about the compression.

The part is $14 at RonAyers assuming its the same as the one in the Ninja.