March 28th, 2011, 07:28 PM | #1 |
ninjette.org member
Name: Brian
Location: Provo, UT
Join Date: Mar 2010 Motorcycle(s): 2008 Ninja 250 Posts: 22
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Strange Problem with Ninja
It's been a while since I've posted on the forums. My 2008 Ninja 250 has been absolutely flawless the past year and some change that I have owned it. I love this bike. It has had all of its scheduled maintenance with the exception of checking the valve clearances (I know, I'll get around to it.) Currently sitting at 7,800 miles.
However, just the other day it developed a very strange problem out of no where. It's also very challenging to explain fully. The bike will still rev though the entire range but when I release the clutch and start moving I only have power up to about 4000rpm. If I continue to push it past that it quickly cuts out and almost dies unless I feather the clutch. And again when I pull the clutch in I have no problem revving the bike though the entire rpm range. You can only imagine how hard/dangerous this situation is. It takes about 30 seconds to get up to 50 mph and I've had to pull over a few times to let cars go by b/c I'm going so slow (pretty embarrassing). It seems like once I get up to speed that the rest of the rpm range is usable but a bit more sluggish than what I'm use to seeing. At first I was thinking that this is a carb issue but I don't see how it could be when I can rev very cleanly all day long in neutral or with the clutch in. I'm really at a loss on this one. Does anyone have an idea before I start tearing her apart? Thanks! Brian |
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March 28th, 2011, 07:35 PM | #2 |
ninjette.org certified postwhore
Name: Sean
Location: Mary Esther, FL
Join Date: Jan 2009 Motorcycle(s): 2008 Ninja 250 1998 HD Road King Posts: A lot.
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Clutch slipping? Is your clutch cable adjusted properly?
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March 28th, 2011, 07:38 PM | #3 |
ninjette.org member
Name: Brian
Location: Provo, UT
Join Date: Mar 2010 Motorcycle(s): 2008 Ninja 250 Posts: 22
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I'm pretty sure the clutch is fine.
Wouldn't the rpm continue to climb if the clutch just wasn't engaging? It's really weird everything is fine until you hit that magic 4000rpm (which actually happens rather soon on the 250 ) |
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March 28th, 2011, 07:47 PM | #4 |
ninjette.org certified postwhore
Name: Brian
Location: Detroit, MI
Join Date: Jun 2010 Motorcycle(s): 2009 Ninja 250R Green Posts: A lot.
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Wow, this one is a toughy. My first guess since it revs but doesnt produce power are the big 3: spark plugs, air, fuel. All of which is pretty easy to check. What you describe reminds me of before I shimmed the needles. It'd easily rev but there wasnt any power until 8k.
If you let the clutch out at 8-10k instead of around 4k rpms, does it exhibit the same power loss? |
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March 28th, 2011, 08:08 PM | #5 |
Join Date: Nov 2008 Posts: Too much.
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pull your plugs and see what they look like. this is a toughy.
if I had to guess, I'd say it's a carb or CDI issue, though I can't back any of that up as this is the first time I've heard of this problem on our bikes. |
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March 28th, 2011, 08:16 PM | #6 |
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Name: 1 guess :-)
Location: SF Bay Area
Join Date: Jun 2008 Motorcycle(s): '13 Ninja 300 (white, the fastest color!), '13 R1200RT, '14 CRF250L, '12 TT-R125LE Posts: Too much.
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Fuel venting or fuel filter.
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March 28th, 2011, 08:52 PM | #7 |
ninjette.org member
Name: Brian
Location: Provo, UT
Join Date: Mar 2010 Motorcycle(s): 2008 Ninja 250 Posts: 22
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Alright guys,
Thanks for all the quick replies. I will look into each of those tomorrow when I have some light. |
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March 28th, 2011, 08:57 PM | #8 |
ninjette.org certified postwhore
Name: Brian
Location: Detroit, MI
Join Date: Jun 2010 Motorcycle(s): 2009 Ninja 250R Green Posts: A lot.
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Goodluck. Keep us posted.
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March 30th, 2011, 12:25 PM | #9 |
ninjette.org member
Name: Brian
Location: Provo, UT
Join Date: Mar 2010 Motorcycle(s): 2008 Ninja 250 Posts: 22
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Update:
Well the bike left me stranded yesterday but that's another story. The bike will still idle and fire up just fine but now when I give it even a bit of throttle it cuts out and dies. Checked the following and they seem to be fine: Air filter Spark Plugs fuel lines oil coolant Does anyone else have any suggestions before I pull the carbs? I really don't want to have to do that. Someone mentioned a fuel filter but I don't see one anywhere? |
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March 30th, 2011, 01:25 PM | #10 |
Join Date: Nov 2008 Posts: Too much.
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March 30th, 2011, 01:30 PM | #11 |
ninjette.org guru
Name: Jeremy
Location: Philadelphia
Join Date: Feb 2011 Motorcycle(s): '04 Aprilia RSV, '10 Bonneville, '10 Ninjette Posts: 359
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I had an old Camaro that behaved exactly like that. You were fine around town, but if you tried to accelerate up to highway speeds, it could barely stay alive. Fuel filter was full of junk.
I guess it could flow enough fuel to keep the engine happy at slower speeds, but once the engine demanded more fuel for higher speeds, it just couldn't flow enough.
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March 30th, 2011, 06:10 PM | #12 |
ninjette.org member
Name: Brian
Location: Provo, UT
Join Date: Mar 2010 Motorcycle(s): 2008 Ninja 250 Posts: 22
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Here's a pic of one of the plugs. They both look pretty much the same. They will both be replaced while I'm at it even though they aren't the problem.
I emptied the gas and checked the filter in the petcock and it was clean so my problem is further down the line. Unfortunately it looks like I'm going to have to dig into the carbs. ...Unless anyone else can give me any more ideas... I've done lots of dirt bike carbs but never a dual carb setup like this. Is there anything I need to watch out for? |
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March 30th, 2011, 06:31 PM | #13 |
Join Date: Nov 2008 Posts: Too much.
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check the DIYs in the new gen tech section. There are quite a bit of carb related threads.
http://www.ninjette.org/forums/showthread.php?t=5586 if you've worked on single carbs before you should be fine, except don't take the carbs apart from one another unless you really need to. work on them as one unit. you have a PM. |
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March 31st, 2011, 07:28 AM | #14 |
ninjette.org member
Name: Brian
Location: Provo, UT
Join Date: Mar 2010 Motorcycle(s): 2008 Ninja 250 Posts: 22
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I just still don't see how it could be the carbs. How likely is it that both of the carbs are gummed up in the exact same way? Wouldn't the bike be mis-firing and sound rough?
Instead it sounds perfectly fine when its running? |
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March 31st, 2011, 11:48 AM | #15 |
Join Date: Nov 2008 Posts: Too much.
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like I guessed in my original post, carbs or CDI. If you don't think it's the carbs, seriously consider the CDI. The new gens had some problems with the CDI when the bike was first released (they still do do to an extent). Most times it's just the tach reading that is erroneous, but I've heard of some people that had running problems due to bad CDIs. Find someone in your area that you could possibly swap it out with to troubleshoot.
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March 31st, 2011, 01:48 PM | #16 |
Long Time Rider
Name: Blue
Location: Charlotte, NC
Join Date: Sep 2010 Motorcycle(s): 2009 Kawasaki Ninja 250R Posts: A lot.
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Is there anything blocking the air intake tube under the passenger seat area?
What have you done to the bike since it last ran fine? How do you ride (hard, easy) and when do you shift? You say it dies and around 4k but if you push past it it's seems like once you get up to speed that the rest of the rpm range is usable but a bit more sluggish than what you're use to seeing. Is this in all gears? Does the bike feel like it is lugging in any gear? What are the riding conditions like? Rain, snow, cold, wind, elevation Here are some things that could be wrong. Poor Running at Low Speed: Spark weak: Battery voltage low Spark plug dirty, broken, or maladjusted Spark plug cap or high tension wiring trouble Spark plug cap shorted or not in good contact Spark plug incorrect IC igniter trouble Crankshaft sensor trouble Ignition coil trouble Fuel/air mixture incorrect: Pilot screw maladjusted Pilot jet, or air passage clogged Air bleed pipe bleed holes clogged Pilot passage clogged Air cleaner clogged, poorly sealed, or element missing Choke plunger stuck open Fuel level in carburetor float bowl too high or too low Fuel tank air vent obstructed Carburetor holder loose Air cleaner duct loose Compression low: Spark plug loose Cylinder head not sufficiently tightened down No valve clearance Cylinder, piston worn Piston ring bad (worn, weak, broken, or sticking) Piston ring/groove clearance excessive Cylinder head warped Cylinder head gasket damaged Valve spring broken or weak Valve not seating properly (valve bent, worn, or carbon accumulation on the seating surface Other: IC igniter trouble Carburetor not synchronizing Vacuum piston doesn’t slide smoothly Engine oil viscosity too high Drive train trouble Brake dragging Like kkim suggested, there may be a problem with your IC Igniter. I had mine replaced under warranty. They are not cheap, so see if you know if someone you can switch with to test to see if yours maybe bad. |
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March 31st, 2011, 06:48 PM | #17 |
ninjette.org member
Name: Brian
Location: Provo, UT
Join Date: Mar 2010 Motorcycle(s): 2008 Ninja 250 Posts: 22
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Problem Solved!
After refusing to take the carbs out I tried a few more things. Checked the vacuum system, checked for fuel when unscrewing the carbs drain bolts, etc... Nothing looked out of the ordinary. Finally when I had things back together enough to start the bike I ran it in PRI (prime) mode on the petcock to see if there was any improvements. It seemed to get a bit better. So I started playing around with the hosing while it was just idling. I disconnected the second hose that comes out of the petcock (goes to the california emissions crap) and wallah! It came right back to life! I really don't understand this as I had disconnected this hosing and inspected it when I took the tank off but for some reason while it was running when I disconnected it it solved the problem. I'm ok with it. Beats taking the carbs out of the bike. |
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April 19th, 2011, 08:43 PM | #18 |
ninjette.org member
Name: Brian
Location: Provo, UT
Join Date: Mar 2010 Motorcycle(s): 2008 Ninja 250 Posts: 22
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My problem is back!
It all of the sudden developed the same characteristics in a matter of minutes on the way home today and left me stranded! Question, I'm trying to figure out the root of all of this and it seems like it may have started right after I filled up last month. Now I can't really remember so I'm just fishing here but what if it was overfilled? Could that cause any problems? Thanks! |
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April 19th, 2011, 08:51 PM | #19 |
Join Date: Nov 2008 Posts: Too much.
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did you try popping the gas cap open to see if that helped the bike to start back up?
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April 20th, 2011, 07:10 AM | #20 |
ninjette.org member
Name: Brian
Location: Provo, UT
Join Date: Mar 2010 Motorcycle(s): 2008 Ninja 250 Posts: 22
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The bike actually starts and idles just fine. It's when I rev past 4000 that everything goes to crap.
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April 20th, 2011, 08:34 AM | #21 |
ninjette.org member
Name: Brian
Location: Provo, UT
Join Date: Mar 2010 Motorcycle(s): 2008 Ninja 250 Posts: 22
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Update:
Found that by turning the petcock to Prime that the bike runs just fine. That leads be to believe that this problem is something to do with the vacuum system. |
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