Sudden engine bog / throttle non-response

zolck510 · June 28th, 2015, 01:50 PM

Hi,

I started my bike ('08 250R, 14000 miles) this morning and was going to run some errands. After about 2 miles, I came to a stop light. I stopped and put it in neutral while I waited for the light to change. The light turned green, I kicked it into first gear, then took off. I immediately noticed that the engine didn't sound right. It was much more of a dull sound, and it sounded like it was bogging down. It was also outputting considerably less power. I fully opened the throttle but instead of jumping, the tach slowly climbed up. I pulled over. As soon as I came to a stop, it stalled.

It started back up again no problem (in neutral) but the idle rev was much lower, about 500 rpm (I set it to 1500). Kicking into first from here would stall it. I had to rev it up some before putting into first, and if I waited a little it would stall again. I got moving because I had to go home, and noticed that taking off from first gear was also harder. It just didn't have the power.

Any idea what might have happened? It seriously was totally ok one moment, and started pulling this stunt about 5 seconds later.

Ghostt · June 28th, 2015, 02:17 PM

Was it hot outside? Next time it does it, try opening the fuel cap, tank vent may be clogged?

Is the bike keep outside? Water in the gas? Drain the carburetors into a clear cup, and check for water.

zolck510 · June 28th, 2015, 06:16 PM

Well so about 2 hours prior to this happening, I rode my bike for about 15 minutes. It was parked for about 2 hours then I started it up again. Couple miles after that was when I noticed this problem.

The bike is kept in a garage but it's not fully indoors. It's just gated. It wasn't hot at all - cloudy day, maybe 75 degrees. I was near empty on gas on Friday and filled it up that day. I'm going to check the spark plugs first and also try some carb cleaners. Next step will be to actually try to clean the carbs...

Motofool · June 28th, 2015, 09:03 PM

Quote:

Originally Posted by zolck510

......... I was near empty on gas on Friday and filled it up that day. I'm going to check the spark plugs first and also try some carb cleaners. Next step will be to actually try to clean the carbs...

Before doing all that, I would simply drain the bowls of the carbs.
It could be that the new fuel you put in the day before was contaminated with water.

zolck510 · June 28th, 2015, 09:29 PM

You mean drain the gas tank and refuel, or drain only the carbs? If I drain just the carbs, wouldn't the possibly contaminated gas left in the tank still give me the same problems?

FWIW, I just tried Seafoam - figured it wouldn't hurt. I think it's a little better now but it also didn't completely fix the problem.

Motofool · June 28th, 2015, 09:41 PM

Quote:

Originally Posted by zolck510

You mean drain the gas tank and refuel, or drain only the carbs? If I drain just the carbs, wouldn't the possibly contaminated gas left in the tank still give me the same problems?

FWIW, I just tried Seafoam - figured it wouldn't hurt. I think it's a little better now but it also didn't completely fix the problem.

The two bowls are the lowest point any contamination could reach.
If water, you could easily see when it stops flowing out and when pure gasoline starts, as those cannot be mixed.
Draining with a small diameter hose into a glass container would make it easier to see.

zolck510 · June 28th, 2015, 10:07 PM

I'll try that tomorrow and see how it goes. Thanks.

zolck510 · June 29th, 2015, 10:25 PM

Started the bike this morning, somehow hoping that letting it sit overnight would do something. Didn't work. The bike started and went up to 2000 rpm before very quickly dropping to 500 and stalling. Came back home after work and drained the carbs. No water, all fuel. Then it took me a couple hours just to get the damn carburetor off. There really isn't much room with the airbox blocking the way. I also couldn't pull it out of the top, so I had to remove it through the side. I'll probably end up doing the battery/airbox mod before putting everything back together to make it easier to put the carb back in. I'm going to clean the carburetor tomorrow and hopefully that does the trick.

Ghostt · June 29th, 2015, 10:36 PM

Don't forget to check the inlet fuel filter. Also might want to check the petcock fo make sure it's working properly.

If your in need carburetor services or parts pm @ducatiman

zolck510 · June 30th, 2015, 08:35 AM

hmm, took a quick look inside the carb this morning before heading to work and everything looks very clean. The previous owner very well may have done a carb cleaning before selling, and that was just 4000 miles ago. I will take it apart and clean everything anyway (might as well) but my hunch is that the carb wasn't the issue. Any further idea if this doesn't work?

hirubhaiambani · June 30th, 2015, 10:03 AM

I am facing the same issue since the last 3 days. Bike starts up fine, when I give it gas, it bogs down but recovers if I give it some choke. I don't have any experience working with carbs and bike maintenance in general so will take it to the shop

zolck510 · June 30th, 2015, 10:14 AM

I have zero experience with bike maintenance too, but the Ninja 250 has tons of info out there and I'm finding it not too complicated. It's also fun to learn how your bike operates. Worst case for me is that if I can't figure it out, that's when I toss it on a truck and bring it to a shop. At least I won't have to pay them the labor cost of stripping it down. I also have a mechanical engineering degree so I naturally find these things entertaining. You should give it a try!

zolck510 · June 30th, 2015, 08:42 PM

Cleaned out the carb. It was already very clean, not much work to do there. Pulled the spark pkugs and they look like this. Could be the culprit. Problem is, I bought the CR8HSA plugs as per the wiki, but apparently the new gen models use CR8E plugs. Will have to reorder and do the plugs later.

jkv45 · July 1st, 2015, 06:35 AM

Check your air filter and intake snorkel - those plugs look overly rich like something is either blocking airflow or you are getting too much fuel for some reason.

A really dirty, oily, or broken-down air filter will block airflow enough to make it run poorly, and occasionally something stored under the seat will partially block the intake snorkel.

zolck510 · July 1st, 2015, 11:29 PM

Air filter was clean. Not sure what's making it run rich. Will explore later.

Finally got the carb back in, connected to the airbox, connected to the engine, and everything sorted out. The bike lives! I need to adjust the throttle cable as it seems like it got loose during the whole process. But it runs like a charm now and I'm glad this process is ovah.

June 28th, 2015, 01:50 PM	#1
zolck510 ninjette.org member Name: Jonny Location: CA Join Date: Apr 2015 Motorcycle(s): 2008 250r Posts: 19	Sudden engine bog / throttle non-response Hi, I started my bike ('08 250R, 14000 miles) this morning and was going to run some errands. After about 2 miles, I came to a stop light. I stopped and put it in neutral while I waited for the light to change. The light turned green, I kicked it into first gear, then took off. I immediately noticed that the engine didn't sound right. It was much more of a dull sound, and it sounded like it was bogging down. It was also outputting considerably less power. I fully opened the throttle but instead of jumping, the tach slowly climbed up. I pulled over. As soon as I came to a stop, it stalled. It started back up again no problem (in neutral) but the idle rev was much lower, about 500 rpm (I set it to 1500). Kicking into first from here would stall it. I had to rev it up some before putting into first, and if I waited a little it would stall again. I got moving because I had to go home, and noticed that taking off from first gear was also harder. It just didn't have the power. Any idea what might have happened? It seriously was totally ok one moment, and started pulling this stunt about 5 seconds later.

June 28th, 2015, 02:17 PM	#2
Ghostt in your machine Name: Scott Location: Summer Shade, Ky. Join Date: Oct 2014 Motorcycle(s): 98 Ninja 250/F12 aka ZX-2R "SERENITY", 91 Ninja 500/A5 aka ZX-5R "Phoenix", 84 Honda GL1200A "SIREN" Posts: A lot. Blog Entries: 25 MOTM - Jun '17, May '16, Mar '15	Was it hot outside? Next time it does it, try opening the fuel cap, tank vent may be clogged? Is the bike keep outside? Water in the gas? Drain the carburetors into a clear cup, and check for water. __________________________________________________ *violente et ignorantia* ZX-2R BLOG *Twitter and Instagram = Ghostt_Scott* *I'm not here to change your mind, just to inform.*

June 29th, 2015, 10:36 PM	#9
Ghostt in your machine Name: Scott Location: Summer Shade, Ky. Join Date: Oct 2014 Motorcycle(s): 98 Ninja 250/F12 aka ZX-2R "SERENITY", 91 Ninja 500/A5 aka ZX-5R "Phoenix", 84 Honda GL1200A "SIREN" Posts: A lot. Blog Entries: 25 MOTM - Jun '17, May '16, Mar '15	Don't forget to check the inlet fuel filter. Also might want to check the petcock fo make sure it's working properly. If your in need carburetor services or parts pm @ducatiman __________________________________________________ *violente et ignorantia* ZX-2R BLOG *Twitter and Instagram = Ghostt_Scott* *I'm not here to change your mind, just to inform.*

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June 28th, 2015, 06:16 PM	#3
zolck510 ninjette.org member Name: Jonny Location: CA Join Date: Apr 2015 Motorcycle(s): 2008 250r Posts: 19	Well so about 2 hours prior to this happening, I rode my bike for about 15 minutes. It was parked for about 2 hours then I started it up again. Couple miles after that was when I noticed this problem. The bike is kept in a garage but it's not fully indoors. It's just gated. It wasn't hot at all - cloudy day, maybe 75 degrees. I was near empty on gas on Friday and filled it up that day. I'm going to check the spark plugs first and also try some carb cleaners. Next step will be to actually try to clean the carbs...

June 28th, 2015, 09:29 PM	#5
zolck510 ninjette.org member Name: Jonny Location: CA Join Date: Apr 2015 Motorcycle(s): 2008 250r Posts: 19	You mean drain the gas tank and refuel, or drain only the carbs? If I drain just the carbs, wouldn't the possibly contaminated gas left in the tank still give me the same problems? FWIW, I just tried Seafoam - figured it wouldn't hurt. I think it's a little better now but it also didn't completely fix the problem.

June 28th, 2015, 10:07 PM	#7
zolck510 ninjette.org member Name: Jonny Location: CA Join Date: Apr 2015 Motorcycle(s): 2008 250r Posts: 19	I'll try that tomorrow and see how it goes. Thanks.

June 29th, 2015, 10:25 PM	#8
zolck510 ninjette.org member Name: Jonny Location: CA Join Date: Apr 2015 Motorcycle(s): 2008 250r Posts: 19	Started the bike this morning, somehow hoping that letting it sit overnight would do something. Didn't work. The bike started and went up to 2000 rpm before very quickly dropping to 500 and stalling. Came back home after work and drained the carbs. No water, all fuel. Then it took me a couple hours just to get the damn carburetor off. There really isn't much room with the airbox blocking the way. I also couldn't pull it out of the top, so I had to remove it through the side. I'll probably end up doing the battery/airbox mod before putting everything back together to make it easier to put the carb back in. I'm going to clean the carburetor tomorrow and hopefully that does the trick.

June 30th, 2015, 08:35 AM	#10
zolck510 ninjette.org member Name: Jonny Location: CA Join Date: Apr 2015 Motorcycle(s): 2008 250r Posts: 19	hmm, took a quick look inside the carb this morning before heading to work and everything looks very clean. The previous owner very well may have done a carb cleaning before selling, and that was just 4000 miles ago. I will take it apart and clean everything anyway (might as well) but my hunch is that the carb wasn't the issue. Any further idea if this doesn't work?

June 30th, 2015, 10:03 AM	#11
hirubhaiambani Ninjette Fanboy Name: HB Location: Missouri Join Date: Jun 2012 Motorcycle(s): 2008 Ninja250 Posts: 307	I am facing the same issue since the last 3 days. Bike starts up fine, when I give it gas, it bogs down but recovers if I give it some choke. I don't have any experience working with carbs and bike maintenance in general so will take it to the shop

June 30th, 2015, 10:14 AM	#12
zolck510 ninjette.org member Name: Jonny Location: CA Join Date: Apr 2015 Motorcycle(s): 2008 250r Posts: 19	I have zero experience with bike maintenance too, but the Ninja 250 has tons of info out there and I'm finding it not too complicated. It's also fun to learn how your bike operates. Worst case for me is that if I can't figure it out, that's when I toss it on a truck and bring it to a shop. At least I won't have to pay them the labor cost of stripping it down. I also have a mechanical engineering degree so I naturally find these things entertaining. You should give it a try!

July 1st, 2015, 06:35 AM	#14
jkv45 Rev Limiter Name: Jay Location: WI Join Date: Jul 2013 Motorcycle(s): '06 SV650n, '00 Derbi GPR, '64 CA77 Dream 305, '70 CL450 Scrambler, numerous dirt bikes Posts: A lot. MOTM - Jun '18, Oct '16	Check your air filter and intake snorkel - those plugs look overly rich like something is either blocking airflow or you are getting too much fuel for some reason. A really dirty, oily, or broken-down air filter will block airflow enough to make it run poorly, and occasionally something stored under the seat will partially block the intake snorkel.

July 1st, 2015, 11:29 PM	#15
zolck510 ninjette.org member Name: Jonny Location: CA Join Date: Apr 2015 Motorcycle(s): 2008 250r Posts: 19	Air filter was clean. Not sure what's making it run rich. Will explore later. Finally got the carb back in, connected to the airbox, connected to the engine, and everything sorted out. The bike lives! I need to adjust the throttle cable as it seems like it got loose during the whole process. But it runs like a charm now and I'm glad this process is ovah.