Blew Something in the Engine...

[Scattcatt]

So it's been a while since I've been on Ninjette, I used to be on every day until about 2 months ago when I seemingly blew my engine. I took it up to the mountains and on my way down I suffered from extreme loss of power and huge foot and a half long flames spewing from my exhaust. The flames would periodically go away and I would regain full power only to have flames screaming from my tail and consequential loss of power again soon after. I rode the bike for a few miles like this trying to get it to a location where I could at least get cell phone service to call for a tow. Once I got off, the entire exhaust all the way up to the engine wasn't red hot... Oh no.... It was BRIGHT ORANGE.

I'm really just looking for some guidance as to what it could be. I've largely gotten 2 opinions:

1) I threw an exhaust valve (though I had just done a valve inspection no more than a couple thousand miles ago)
2) I jacked up the cylinders somehow

My engine performance upgrades are a full Yoshi exhaust, the Ecotrons FI kit, and pod filters. The engine itself has somewhere around 17 or 18,000 miles on it so it's not terribly old.

I'm about to finally drop the engine out of the bike tonight after simply not wanting to touch it out of frustration for the past 2 months and I'll start with the valves and work my way to the pistons. Is there anything else I should check along the way? I saw nothing in my searches on Ninjette regarding something similar besides backfires and the like.

Thanks!

[Racer x]

My guess is something in one of the carbs went wrong. To get fire to spray from your exhaust and have enough energy to heat your exhaust to the point it was glowing red takes fuel. Lots of fuel and air.
Just a made up scenario. One jet unscrews and falls into the bowl. Now instead of a tiny hole you have a giant hole. And the bike is still running on the other side. One piston is just pumping fuel into the exhaust system. The other is feeding it with air and fire to make a nice blow torch. Just a guess But I have seen that happen before .. Not to me

[Scattcatt]

Well the fuel injection kit will come off too, works a little different than the carbs but if that's the problem then it will be a very easy fix if something as simple as something that vibrated loose in the kit. Thanks for the heads up with that one @Racer x, you always have pretty good ideas, definitely something worth checking out.

[choneofakind]

Subscribed. I want to make sure this was your bike, not your efi kit jk, I'm curious to know what happened.

I also want to pick your brain about your desired lamba map. I think your data might help me with my rich top end and less than optimal low end.

[80MPHdownhill]

Originally Posted by Scattcatt

1) I threw an exhaust valve (though I had just done a valve inspection no more than a couple thousand miles ago)

Can't be that. If you lost an exhaust valve, the header on that side would not be red hot, it would be lukewarm, since there can be no combustion (and thus no heat) in a cylinder that has dropped an exhaust valve.

I don't know what "jacked up the cylinders" means. I don't think that's a very commonly used diagnostic term for an internal combustion engine problem.

My guess is your engine is fine internally, and your problem was some kind of air to fuel ratio issue.

[Scattcatt]

Originally Posted by 80MPHdownhill

Can't be that. If you lost an exhaust valve, the header on that side would not be red hot, it would be lukewarm, since there can be no combustion (and thus no heat) in a cylinder that has dropped an exhaust valve.

I don't know what "jacked up the cylinders" means. I don't think that's a very commonly used diagnostic term for an internal combustion engine problem.

My guess is your engine is fine internally, and your problem was some kind of air to fuel ratio issue.

Why couldn't ignition occur without the valve? The AFR would still be the same so it could combust which would mean that it would just combust through the header, right? Is there something I'm missing? Because that totally makes sense to me.

I just used the term "jacked up" since it was something that came about briefly in a discussion with some other motorcyclists, damaged rings perhaps?

[80MPHdownhill]

Yeah, what you'd be missing is compression. Because without an exhaust valve, you have zero compression. Without compression, you can't have combustion. You'd have a zero compression, "dead" cylinder that would be incapable of generating any real heat, certainly incapable of generating enough heat to make your exhaust pipe on that side glow.

Damaged rings would not cause the problems you described.

IMO you have a fuel delivery problem.

[Racer x]

I missed the EFI part. Sorry. That is something I have seen also. An injector wire grounding and spraying full flow. Or stuck open and just spraying

[rabies]

if you dropped a valve your cyclnder walls/pistons and head are chunked up.
drop a valve in motor = drop a grenade in motor.

best thing to ever do this...crack the valve cover open..check valve tension. take off exhaust and peak inside. take off carbs and peak inside motor

[JA-Moo]

My guess a sunk valve seat or bad valve clearance. The red pipe is gas burning in the pipe. so the valve isn't closing all the way.

[lgk]

Originally Posted by JA-Moo

My guess a sunk valve seat or bad valve clearance. The red pipe is gas burning in the pipe. so the valve isn't closing all the way.

i was thinking the exhaust valve is stuck open slightly.

then it would ignite in the exhaust after compression.

[Scattcatt]

I've got the exhaust off, peering into the exhaust side of the engine is difficult because the forks are in the way though, I'll go pick up on of those mechanics extension mirrors for a better look. Is there any concern for the exhaust itself after being exposed to such high temps? I'm not sure if Yoshi's run catalytic converters or anything in them that might be sensitive to the abnormal extreme heat over such a prolonged period. The riders behind me did say that there were things coming out from my exhaust, but it was very dark and I see an irregular carbon pattern inside of the exhaust pipes which may suggest small flakes broke loose or something.

[lgk]

i dont have a yoshi exhaust, but i'm going to guess it does not have a CAT.

its most likely ok.

[Scattcatt]

Thanks @lgk, I figured it was probably okay, just wanted a second opinion before it got to the point of me putting the exhaust back on.

[JA-Moo]

Originally Posted by Scattcatt

Thanks @lgk, I figured it was probably okay, just wanted a second opinion before it got to the point of me putting the exhaust back on.

Do a compression check....

[lgk]

after the compression check, show us a pic of the plugs

[Scattcatt]

The compression test will have to wait a little bit, I drained all of the fluids out and I don't have a tester that goes to a high enough psi, I'll pick one up within the next couple of days. These are my spark plugs for now though.

[Scattcatt]

First potential lead for this problem:

I've done the two valve inspections myself so far on the bike, both times I used the video DIY here on ninjette which now no longer exists. If I recall correctly, the proper procedure was for both of the lobes on the cams to point away from each other when at 2|T for both cylinders, correct?

So this meant one rotation around, at 2|T the cylinder 1 lobes would be in inspection position, and the next rotation around at 2|T the cylinder 2 lobes would be in inspection position, right?

It's been a little bit, but I don't remember using 1|T. Now it appears that things are exactly the opposite. The only way to get opposing lobes in the bike is at 1|T. It seems extremely coincidental that things somehow got shifted around exactly 180 degrees but I'd imagine it's a problem.

How this happened I have no idea, a loose cam chain perhaps? Even if that's the case, it seems highly unlikely that the chain would catch again at exactly 180 degrees around. Remember that I rode the bike for a couple thousand miles since the last inspection without a problem.

Thoughts?

[EMSRacer07]

Originally Posted by Scattcatt

First potential lead for this problem:

I've done the two valve inspections myself so far on the bike, both times I used the video DIY here on ninjette which now no longer exists. If I recall correctly, the proper procedure was for both of the lobes on the cams to point away from each other when at 2|T for both cylinders, correct?

So this meant one rotation around, at 2|T the cylinder 1 lobes would be in inspection position, and the next rotation around at 2|T the cylinder 2 lobes would be in inspection position, right?

It's been a little bit, but I don't remember using 1|T. Now it appears that things are exactly the opposite. The only way to get opposing lobes in the bike is at 1|T. It seems extremely coincidental that things somehow got shifted around exactly 180 degrees but I'd imagine it's a problem.

How this happened I have no idea, a loose cam chain perhaps? Even if that's the case, it seems highly unlikely that the chain would catch again at exactly 180 degrees around. Remember that I rode the bike for a couple thousand miles since the last inspection without a problem.

Thoughts?

Hey man was wondering when you were going to get back to your bike.

Spark Plugs look great, especially for what happened. Combustion chamber must be fine. Does look like they have some soot on them though.

Way I do valves in my car, ninja and etc its basically as long are you measuring on the lowest point, the lobe is the farthest from the rocker arm. Ppl like using the 1T or 2T method but its all the same as long as the lobe isnt pushing on the rocker as you check clearance.

If your clearances are good and u know your not getting a bad spark or combustion. Possible leak around the spark plugs or leak somewhere on the head. Compression check is a must at this point.

Check Compression
Check injectors (see how they are spraying)
Did any check engine light come up on the ECU?

Good luck man

[80MPHdownhill]

I still don't see why you think you have internal engine damage.

[Scattcatt]

@EMSRacer07 I'm starting to get excited to get back out too, I was just really frustrated at first.

Peering down through the spark plug holes it looks like the piston heads are extremely sooty as well.

So does the 1 or 2|T make a difference? I would have thought that a slip from 1 to 2|T would have rotated the pistons 180 degrees without changing the timing of the valves the same amount. Seems like trouble to me, right?

Bought a compression tester so I'll give that a shot once I seal the engine all back up and get fluids in it. Checked over the intake and exhaust sides of the engine and nothing looks abnormal there.

I also checked the wiring on the fuel injection and looked at the throttle body. Everything looks okay but I have not yet tested the injectors while they're spraying (dead battery).

No check engine light, that's something I definitely would have noticed with all of my gauge looking that night when it all happened.

@80MPHdownhill I'm going through everything, I suspect it's engine damage because that's what everyone local here is saying. No one has suggested the fuel spay except on here, so I'm covering it all.

I recently was concerned about a light slapping noise in the engine before the last valve inspection to begin with which I thought may have been the cam chain. If I was right then it could be possible that the cam chain has stretched allowing things to slip around in there. Only reason why I didn't worry about it too much was because I read in a thread somewhere on here that a some other people experience the same thing while the bike is cold and when the engine warms up the sound goes away which was exactly what I was experiencing.

My goal here is just to hit every angle, I don't want to miss something, I've already been down for 2 months and I'm not looking to rush this, skip something, and end up down again. Even if that means I find something that isn't the problem yet but could be in the future.

[Motofool]

Originally Posted by Scattcatt

First potential lead for this problem:

I've done the two valve inspections myself so far on the bike, both times I used the video DIY here on ninjette which now no longer exists. If I recall correctly, the proper procedure was for both of the lobes on the cams to point away from each other when at 2|T for both cylinders, correct?

So this meant one rotation around, at 2|T the cylinder 1 lobes would be in inspection position, and the next rotation around at 2|T the cylinder 2 lobes would be in inspection position, right?

It's been a little bit, but I don't remember using 1|T. Now it appears that things are exactly the opposite. The only way to get opposing lobes in the bike is at 1|T. It seems extremely coincidental that things somehow got shifted around exactly 180 degrees but I'd imagine it's a problem.
.......
Thoughts?

You don't recall correctly.

Sitting on the bike, cylinder #1 is the one on your left.

1T mark is for any of the two TDC for cylinder #1.

For TDC between compression and power strokes of cylinder #1, the lobes of the cams for cylinder #1 should be pointing up and away from each other.

Same applies for 2T mark, cylinder #2 and its cams.

The timing for the valves for the new-gen is as follows:

Inlet valves open at 36 degrees before Top Dead Center

Inlet valves close at 56 degrees after Bottom Dead Center

Exhaust valves open at 61 degrees before Bottom Dead Center

Exhaust valves close at 31 degrees after Top Dead Center

All valves are open during 272 degrees in a asymmetrical way.

http://www.cdxetextbook.com/engines/...ngdiagram.html

Link to original page on YouTube.

Crankshaft is 180 degrees.

Range for ignition timing is as follows:

From 10 degrees before Top Dead Center at 1,300 rpm
to 35 degrees before Top Dead Center at and after 4,000 rpm

Your spark plugs show extreme lean condition, if they have been working for a while.
That condition increases the temperature (over-cooking and igniting the carbon deposits and making them fly away with the exhaust, frequently fouling the spark plug) and makes the propagation of the flame very slow (combustion continues while gases are exhausted).
It seems to me that your injector feeding that cylinder with hot exhaust is clogged or working improperly, delivering less than ideal fuel.

It could also be a late spark timing for that cylinder.

[EMSRacer07]

well if you think you jumped teeth or might have broken the cam chain why dont you just check the tensioner and see if its worn, broken, etc.

And since you have valve cover off you can count the links between cam sprockets. I personally dont know how many your supposed to have but i know there is a right amount and that will tell you if it has stretched as well.

[Scattcatt]

@Motofool

Alright so I'm okay so far then I think. Good, that's a plus. Thanks for the clarification on that one, for a change I'm glad my memory was completely off lol.

@EMSRacer07

I'm trying to find the stretch specs in the service manual on the cam chain. I remember I found them somewhere once before when I was concerned about my cam chain, I just can't find it again though. I'll take a look at the tensioner as well. Off to do the valve clearance inspection again for now.

[Motofool]

Originally Posted by Scattcatt

I'm trying to find the stretch specs in the service manual on the cam chain.....

A new 20-link length under 5 kg tension should measure 127.0 ~ 127.4 mm.

The service limit is 128.9 mm.

Since the chain may wear unevenly, take measurements at several sections all around.

Never rotate the engine counter-clockwise or without the chain tensioner.

[Scattcatt]

Do you know of the chain tensioner puts an equivalent of 5kg on the chain? Or will I have to physically weigh it down like the drive chain?

All valves are still within spec by the way, so no problem there.

[Motofool]

No, I don't know what tension the tensioner applies.

The described test is intended for measuring the chain out of the engine, under moderate tension (10 lb aprox.) since it is not possible to measure 20 links in a straight line, I believe.

However, you can measure 10-links between the sprockets, keeping the chain taught.

[Scattcatt]

thanks @Motofool, cam chain checked out okay, just finished checking the entire length of it. So really the next step from this point would be to test compression.

[JA-Moo]

To answer 2 questions, Kawasaki has at least two different locations to check valve clearance. One is with the lobe pointing directly away from the valve. And some with the lobe on it's side. You need to find out the exact way to check the clearance.

The second, Is with a glowing red hot pipe, that means burning gasses are flowing between an open valve and seat. The seat and valve is exposed to tremendous heat, that it wasn't designed for. This can burn the valve and damage the seat, even over heat the valve seals.

[Scattcatt]

@JA-Moo I followed the valve clearance inspection method in the service manual for the 250, so I'm not too worried about the valves. They all came back within spec anyway.

I'm assuming anything that you said that could have been damaged by the heat would probably shot up in a compression test, right? Good news is that cylinder one passed the compression test, but only barely in spec. Minimum is 142psi, the compression measured was 145psi over 3 different trials.

Unfortunately I have not been able to test cylinder 2 yet.... The fitting at the end of the compression tool got stuck in cylinder 1 lol... Just my luck, right? So now I red locktite'ed the compression hose down there to the fitting so I can pull it all out tomorrow and reset for cylinder 2.

The good news is that I got the bike started and it ran without a problem which made me really happy! I might be able to get the bike back on the road within a day or two now!

[JA-Moo]

Am I right, that you basically changed nothing?

[Scattcatt]

You're 100% correct, I've changed absolutely nothing which makes this so much more confusing... Everything so far has checked out to be okay.

I'm running the engine again right now, I managed to get that fitting out and I'll run a compression check on both cylinders again. If this comes back okay, then I seriously have no idea where to go next.

[Motofool]

Originally Posted by Motofool

.........Your spark plugs show extreme lean condition, if they have been working for a while.

That condition increases the temperature (over-cooking and igniting the carbon deposits and making them fly away with the exhaust, frequently fouling the spark plug) and makes the propagation of the flame very slow (combustion continues while gases are exhausted).

It seems to me that your injector feeding that cylinder with hot exhaust is clogged or working improperly, delivering less than ideal fuel.

It could also be a late spark timing for that cylinder.

[Scattcatt]

Compression results:

Cylinder 1 averaged 145 psi over 3 trials
Cylinder 2 averaged 157 psi over 3 trials

They're both within spec and within a 10% difference though close to the extremes for both constraints. The engine was at running temperature.

@Motofool those plugs were fairly new so I'm not entirely sure how accurate the read out would be on them, but I'll definitely check into the ignition timing as I suspect at around idle it's off anyway but I don't think this will be the case for the higher rpm's, but it's worth a look anyway.

[80MPHdownhill]

As I told you very early on, you don't have any internal engine damage.

You have posted nothing that would have suggested internal engine damage.

You have been given, and blindly accepted, some of the most bizarre diagnostic advice I've ever seen.

Thankfully you didn't start disassembling the engine (for no reason), which would have been the end of your bike.

Again, red hot exhaust pipes are a fueling or ignition (although highly likely fueling) problem. That has nothing to do with "broken" exhaust valves or "jacked up" cylinders.

[JA-Moo]

Originally Posted by 80MPHdownhill

Again, red hot exhaust pipes are a fueling or ignition (although highly likely fueling) problem. That has nothing to do with "broken" exhaust valves or "jacked up" cylinders.

I will disagree, A stuck/sticking valve or too tight of valve WILL cause a red hot exhaust. Been there, done that..... I agree it's not a broken valve.

The main thing, is the cause needs to be found......

[Motofool]

Originally Posted by Scattcatt

...@Motofool those plugs were fairly new so I'm not entirely sure how accurate the read out would be on them,.......

If the plugs have been working for less than several hundred miles, their color is meaningless.

[Scattcatt]

Just an update, I still haven't figured out what's going on and the bike's performance is getting progressively worse. My last test I made it about 6 feet out from my driveway before encountering problems that rendered the bike completely unrideable.

I've been in touch with the owner of the company of the fuel injection system and we're working on ruling that out through various tests. It looks like this may be contributing to the problem since every time right before the problems occurs, the program used to log data is shutting down which means that there is a power failure going on somewhere.

I've also been talking to @EMSRacer07 quite a bit outside of Ninjette about the problem and the plan is to conduct two other tests while the ECU data logs are being reviewed: ignition coil tests, and fuel injector tests as discussed previously.

I've taken 3 recordings on on my GoPro but I seriously doubt they provide anything of significant value, but still, if you have the time, feel free to watch through them and see if they raise any ideas for problems and solutions. They are completely uncut and unedited so they're quite long.

This test is from a first person view, probably the least useful since the engine isn't that audible.

Link to original page on YouTube.

This test provides some idea of how frequent the problem is becoming, I barely made it out of my neighborhood. It's an action shot of the muffler.

Link to original page on YouTube.

This was the most recent test, the test where I made it no where. Probably the most useful test. Only need to watch until I start walking the bike, I just left the camera recording on accident. It's the same action shot of the muffler as before.

Link to original page on YouTube.

Anymore ideas? Thanks again guys

[80MPHdownhill]

Originally Posted by Scattcatt

I've been in touch with the owner of the company of the fuel injection system and we're working on ruling that out through various tests. It looks like this may be contributing to the problem since every time right before the problems occurs, the program used to log data is shutting down which means that there is a power failure going on somewhere.

Hmm, never would have guessed that.

As I said from day 1, the problems you were having describe a fueling problem. That's the cause of red hot exhausts.

Being an aftermarket system, who knows what's wrong with it.

In general, though:

1. Problems with the unit powering up (like you've described). Although if the unit is powering, that would normally mean you're bike is dead. Not running at all.

2. You should be able to check all the sensors (crank position sensor, engine speed sensors, engine temp sensors, throttle position sensor, etc.) with a digital multimeter. You'll need the specs (hot and cold, if applicable) for all the sensors.

3. You could have a wiring problem. Either a bad connection somewhere in the system, a partially broken wire, a bad ground (check all your grounds very carefully!), etc. Go through every inch of wiring and visually inspect for breaks, etc. Disconnect and reconnect every single connection, clean with contact cleaner.

4. You could have a problem inside the ECU, like a crack in the soldering on the circuitboard, etc. This isn't that common.

5. Bad fuse or a bad relay.

6. You could have an ignition problem, but I'd focus on the fuel system first.

You really need to have a systematic plan of going through all of the above one by one, to isolate and find the problem.

I'm glad to see you didn't start disassembling your engine, though.

Do you still have your carbs? Can you put them back on?

Do you have a digital multimeter? You really need one to systematically diagnose this kind of problem. They are available everywhere for under $20.

Good luck!

[Scattcatt]

Digital multimeter is on the way, should arrive either tomorrow or the following day so that's a plus for all the testing.

Been thinking about doing a benchline test with the carbs back on there I just can't track down the plug for the CDI. I'll see if I can dig it up later this evening after work.

Thanks! Probably going to need a little luck on this!