Hi all, mine is a 2005 Ninja ZZR250 with 2000 miles on the odo, and usually runs very strong. But on this afternoon, air temperature about 80F, I was in stop and go traffic with red light after red light, and the temperature needle moved up to mid-range, from the usually 10%. After a bit, the engine just lost power and died, but during riding, not during idling. This happened once before, when I was riding at low rpm on a warm day. Immediate restarting would not restart it. After the engined has sat for a few minutes, it would restart, and would run strong as before on low and high RPM. And on high RPM and high speed, the engine would cool back down. Has this happened to anyone? What exactly killed the engine? Overheating (though the temperature needle was never higher than 55% on the gauge), or carb flooding? or what? Any input would be appreciated.

AM

I make a point to shut off the engine when I know I'll be at a light for a long time (and obviously when there's no risk of being rear-ended). The manual says to not idle it for more than 5 minutes (on the new gens anyway). I figure if the engines already hot, its a hot day, and there's no cooling air going over it it could probably get way too hot.

Just my 2 cents. I can't think of anything that's mechanically wrong with your bike. Obviously if it only quits when it's too hot, I'd just try to keep it cooler.

I think they have a temp switch in there that is a fail safe. Where it kills the motor when it starts to get too hot.

Mine did that the other day. It just happens. Just try to make a point of taking roads that move along a bit better. :)

Thanks buddy. And you're in FL, way hotter than here in BC. I'll take your advice at long red lights. - AM

After I restarted the bike, I stayed at a lower gear/higher RPM, and the engine seemed to run a little cooler. I'll check it out again next time I ride. Thanks for the feedback, Apex. - AM

I think they have a temp switch in there that is a fail safe. Where it kills the motor when it starts to get too hot.


not that I'm aware of.

After I restarted the bike, I stayed at a lower gear/higher RPM, and the engine seemed to run a little cooler. I'll check it out again next time I ride. Thanks for the feedback, Apex. - AM
Hmm, maybe the waterpump is flowing more water at the higher RPM's. Hmm, I'll have to look into that...

You've sent me on a hunt now. :D

not that I'm aware of.
My last bike had a setup like that, so I figured this one may too. It would kill the motor and throw up an idiot light at me. :)

I have been corrected/edjumacated!!! :D

I'm not saying you're not correct, but that I've never heard of such a thing on 250 ninjas and never have on any other bike.

what type of bike, previously, did you have that did that?

Hmm, maybe the waterpump is flowing more water at the higher RPM's. Hmm, I'll have to look into that...

You've sent me on a hunt now. :D
Let's compare notes in a bit. - AM

A lower gear and higher RPM will flow more coolant.

I'm not saying you're not correct, but that I've never heard of such a thing on 250 ninjas and never have on any other bike.

what type of bike, previously, did you have that did that?
GS500

It died on me once, looked down and the light was on. I let it sit for a minute (I was putting around a mall parking lot at low speed), shut off the bike, turned back on, and it started. Of course I could be totally wrong. I'm almost positive the guy at the dealership told me it had a thermal switch on it as a fail safe.

Then again, that was over 10 years ago. :)

Let's compare notes in a bit. - AM
Here you go:

http://faq.ninja250.org/wiki/Cooling_system

The GS500 is an air cooled bike..no fail-safe switch on it. The red light that you saw illuminated is most likely the low oil pressure light.

The GS500 is an air cooled bike..no fail-safe switch on it. The red light that you saw illuminated is most likely the low oil pressure light.

Possibly. Like I said it was 10 years ago.

Isn't the radiator fan on these bikes supposed to keep it from overheating at a standstill?

Isn't the radiator fan on these bikes supposed to keep it from overheating at a standstill?
It is supposed to, but it is best to keep it from even happening.

My buddy's ZX10 is the same way. Kawi suggests shutting it off if sitting at a light for a little bit.

This sounds like it could be another 'what type of oil should I use' discussions. The guy at my dealership told me that I should wait until the fan comes on before I start to ride (to be sure that it is warmed up). I am in Canada though, with igloos, polar bears and such.

Isn't the radiator fan on these bikes supposed to keep it from overheating at a standstill?

Yes, when the engine exceeds a certain threshold temperature, the rad fan is supposed to automatically turn on. So, one of the things for me to check is the fan, to see if the fuse is blown or any connection is broken. Any idea where the fuse box is on a 2005 ZZR? - AM

I was always under the impression that when you first turn off an engine it gets hotter before it starts to cool off. If this is the case then turning it off at a red light, which is only a few minutes, would make the engine get hotter so when you restarted you are starting off with an even hotter engine.

Make sure your fans are working properly. Make sure your coolant is at the correct level. Add some of that super cool stuff (water wetter or whatever it is). If you're having trouble at 80 degrees, which isn't very hot, maybe the thermostat needs replaced.

I had something similar happen to my 2007 250r.

First, I would suggest a complete flush of the coolant with 50/50 green and a full bottle of water wetter.

Flush and flush all of the residue in the coolant system to get all of the crud out. There may be plenty in there. You'll have to fill, start, empty, refil, start bike, empty, etc.

Next, I would put in a healthy supply of SeaFoam. Whatever this stuff is, it works bigtime.

Third, I would empty the tank and put in fresh fuel. Ethanol gums up within 2 weeks of sitting there and will cause the fuel problems that you experienced.

Fourth, I would rebuilt the carbs.

Fifth, I would synch the carbs.

Sixth, I would replace the spark plugs with the proper replacements and gap.

I was always under the impression that when you first turn off an engine it gets hotter before it starts to cool off. If this is the case then turning it off at a red light, which is only a few minutes, would make the engine get hotter so when you restarted you are starting off with an even hotter engine.

Make sure your fans are working properly. Make sure your coolant is at the correct level. Add some of that super cool stuff (water wetter or whatever it is). If you're having trouble at 80 degrees, which isn't very hot, maybe the thermostat needs replaced.
I haven't heard this before - but I do know that starting an engine does more wear damage than leaving it on does.

I think there are explanations for both:
1. "when your first turn off an engine it gets hotter before it starts cooling off" - This might be true, because once you turn off the engine, the coolant stops circulating at once, so, there could be local hotspots which could have been cooled that is not.
2. "starting an engine does more wear damage than leaving it on does" - this is true when you start a cold engine which has been sitting for a while; the first few revolutions would partly be metal-on-metal without lube, but this doesn't apply to the engine at the red light.
- AM

any chance you just filled up the gas tank and it was full to the top? i am wondering about vapor lock though probably a long shot.

Interesting idea - if the tank was full to the top and sealed air tight, that might happen. But not in this case. I actually thought I was running out of gas, since I had over 200 miles on the tip meter, but not that either. There was gas. - AM

Somebody also suggested possibly tight valves. If so, any idea how that developed? - AM

I actually thought I was running out of gas, since I had over 200 miles on the tip meter, but not that either. There was gas. - AM

did you flip it to reserve just to make sure it wasn't a gas delivery problem? I've seen people think they have an intermittent engine dying problem when it really was that the fuel was getting low and they needed to switch the petcock to reserve.

200 miles is quite a lot. how many miles do you normally go before you need to switch to reserve?

Hey Mr. Kim, I hope you've been well and riding up a storm on that twisty road of yours. Anyway, I did look into the tank, and saw gas there. Still, I did flip it on to reserve, but by then, it had died. After it restarted, it stayed on reserve until I refueled later the same evening. By then, the traffic had lightened up, and the air temp cooler, so, I rode it the same way as I always do, and it did just fine, with the temp needle around 10% the whole way back. I've ridden only about 500 miles since I bought the bike in December. Last couple of times, I fueled up at about 350km or about 220mi. Still fuel in the tank and not on reserve. - AM

Aloha Anthony,

Doing well here... having fun when time permits. :)

Here's a pic of a petcock with a reserve setting. The taller of the two is the on position and it will flow gas from the tank as long as the level is above the pipe. The shorter of the two is the reserve position and as you can see it will pull fuel from the tank till it's almost empty.

Many times as you approach the level of gas when the petcock is in the on position, fuel will stop flowing if the tube is above the fuel level. hard cornering or even leaning the bike at a long light might drain the carbs of fuel needed to run.

http://i219.photobucket.com/albums/cc128/terylsdad/CutPetcock.jpg

I would think that the fan switch is bad if its not turning on to keep some air flowing on the radiator. you can test the fan buy disconnecting it from the switch and jumping it.

Mr. Kim, thanks for the pic. Makes it very clear. The only reason I doubt it's a fuel problem is that it happened once a few days before. Same thing. After a few minutes, I restarted it, and rode it home. Yesterday was the next time, and I rode for maybe 8 miles before it konked out. If it was a fuel problem, wouldn't it be no go for even these few miles? Just thinking aloud.
- AM

Yes, sir... you're most likely correct. How many miles between episodes of it konking out? Were you leaning the bike to the right at an intersection perhaps?

Only other thing I can think of is a heat related ignition problem... perhaps the CDI or ignitor? I have not heard if the pregens have problems with them, but the new gens seem to be plagued with questionable units.

Yes, sir... you're most likely correct. How many miles between episodes of it konking out? Were you leaning the bike to the right at an intersection perhaps?

Only other thing I can think of is a heat related ignition problem... perhaps the CDI or ignitor? I have not heard if the pregens have problems with them, but the new gens seem to be plagued with questionable units.

Between the episodes - 3 days, about 10 miles. The first time was on a twisty, normal speed, warm day. The second time was straight city streets with lots of red lights. I'll take the bike to a shop for a check-up in a week or so. I'll let you know. Thanks for the input. - AM

http://i186.photobucket.com/albums/x70/AnthonyMarr/DSC01532-crop.jpg

<a href="http://s186.photobucket.com/albums/x70/AnthonyMarr/?action=view&current=DSC01532-crop.jpg" target="_blank"><img src="http://i186.photobucket.com/albums/x70/AnthonyMarr/DSC01532-crop.jpg" border="0" alt="Photobucket"></a>

I don't think the engine gets any hotter after turning it off as you've removed the only source of heat from the engine. Yeah you kill the water pump, but there's just nothing going on in the bike to get it any hotter. How much good is an idling water pump going to do anyway? The fan should still come on if it got to that point, but it's usually on already when I decide to switch off the engine.

I'm not too worried about doing damage while cranking the engine either. It's already hot, got good oil distribution. You only have to crank it over once or twice for it to come back to life. I try to wait for the lights to go out before I rev it up too, just so that everything has the pressures that it needs.

I think this is the kind of thing we could argue about for ages though. There's no real proof either way. I'll keep doing what works for me and I'll probably end up coming here if I ever have problems with a burnt out starter.:thumbup:

I don't think the engine gets any hotter after turning it off as you've removed the only source of heat from the engine. Yeah you kill the water pump, but there's just nothing going on in the bike to get it any hotter.

Anthony was on to something in this post (http://www.ninjette.org/forums/showpost.php?p=66109&postcount=23). In total, the entire engine as a whole will not get hotter, as you're correct that there's no more combustion going on. But the engine is always at significantly different temps when running, the top end of the engine is much hotter, and the circulating coolant continues to remove heat from the hotter parts of the engine and help transfer it not only out of the bike but in some sense to other cooler parts of the engine. That said, if things are alreadying in an overheating state when things are circulating, I'd agree that the best thing to do may be to shut everything down and let the engine cool as a whole.

I tested my theory today. I was stopped on a road while they were resurfacing ( flagman was letting one lane of traffic alternate). I could see it was going to take a while before the line of traffic I was in was going to move. My temp was at 185. I turned off the bike. It was only a few minutes before we were allowed to go so I started the bike back up. The temp was at 196 now. As I started to ride down the road my temperature still rose up to about 200. My fans don't come on until 220.

I don't know what this proves but it was interesting to see how the temperature not only rose when I turned the bike off but also after I started it and rode up the road for a few minutes until it began to cool off.

That is the coolant temp that is being measured though. Without the pump going (and air through the rad), it makes sense that the coolant would get hotter. That the coolant is getting hotter generally means that the engine is getting cooler.

the coolant is being used as a heat exchange medium. If the water pump stops flowing the coolant, it makes sense the coolant will get hotter as it absorbs the heat from the engine. What is not good is that the coolant is not longer flowing and is not taking heat away from the engine.

Maybe I'm just not understanding this right. If the coolant is absorbing heat from the engine, how is it not taking heat away from the engine?

the coolant absorbs some heat, but without it flowing, it does not make it to the radiator so the heat can be taken out from the coolant and returned to the engine to draw even more heat out.

the coolant absorbs some heat, but without it flowing, it does not make it to the radiator so the heat can be taken out from the coolant and returned to the engine to draw even more heat out.

Yup.

Break down the cooling system-
Radiator
Water Pump
Thermostat

While the engine is running, coolant is being pumped through the radiator and the water jackets in the engine via the water pump. The thermostat serves two functions: one is to allow the engine to get up to operating temperature quickly, and the second is the control the flow of coolant. The radiator is where the heat absorbed by the coolant is dissipated. If the thermostat were removed, coolant would flow too quickly, and the cooling system would not operate as efficiently as it could with the thermostat in place. Should the engine be shut off, coolant will stop flowing and dissipating heat (except for the coolant still in the radiator), and the coolant temp will increase a few degrees.

Gotcha. I had always figured it was better to just shut the engine down and cool it that way than by running the pump at idle. I've got no idea how much more efficient the pump is at higher RPMs than at idle. It's just the impression that I've always had about the system.

There is still a part of the cooling system not discussed here and that is you need air flowing through the radiator to properly dissipate the heat the radiator is taking out of the coolant. When you ride, the air flowing through the radiator does that job. when you are standing still and idling, there is no air flowing through the radiator. As a safety feature, the fan will kick on to draw air through the radiator. Still, it's not enough air flow and even with the fan running, you'll overheat and the result is that the fluid "boils" and makes it way out that overflow tube which exits down by the rear tire.

spark plugs also remove heat depending on the exposed surface in the combustion chamber , ia am new here and recently bought my bike the local dealer gave me NGK CR7HSA plugs and i live in hot weather at low speeds or a light my temp gauge climbs real close to red before the fan kicks on. i changed to the recomended cr8hsa plugs and adjusted my valves towards the loose end at my gauge and fan still act the same maybe just alittle slower warming up...the factory gauge reads hot if your engine dies you need maintenance

Gotcha. I had always figured it was better to just shut the engine down and cool it that way than by running the pump at idle. I've got no idea how much more efficient the pump is at higher RPMs than at idle. It's just the impression that I've always had about the system.

Another question: Is the water pump driven directly by the engine via a belt/chain so that the speed of coolant circulation is directly proportional to the RPM, or did I read earlier that the speed of the water pump is regulated by the thermostat?

Anthony, you have a PM.
:)

Just an update for all. I did NOTHING to the bike, just rode it differently - lower gear, higher RPM (I was trying too hard to push for some fuel economy record). The bike performed perfectly (though I haven't attempted the prolonged stop-and-go traffic again, so still some lingering questions remain). If the problem recurs, I'll let you know. Thanks for your input, brothers!

Anthony