Ninja 250 only "running" on 1 cyl.

Background (since I've got no ideas).

- Bike was bought in "poor" running condition. Didn't have any desire to idle, and made a ton of valvetrain noise.

- Initial top speed, est. 20mph (pick a gear, you aren't going any faster - 5k rpm tops)

- Battery, plugs, air filter, oil and oil filter were changed, carbs cleaned out, valves adjusted.

- Reassembled motorcycle. Same problems as before. Didn't sound quite as horrid.

- A week elapsed, battery is dead as a doornail and the bike doesn't run at all.

Spent the last few hours with a friend in my garage trying to fire up a yellow '04 EX250. This was mostly unsuccessful up until about 15min ago when it actually started making some noises that sounded a whole lot like an engine trying to run. The left header pipe was warm, like it had been used to carry away some exhaust gases in the recent past. The right header pipe was as cold as ice.

The things we could check, or "guess" at least are that there's some compression going on as there's air coming out the exhaust pipes with decent pressure as the bike is cranked. Spark is definitely happening. I cannot say for sure fuel is getting to the right cylinder, but it is definitely getting to the left. We tried starting fluid, and carb cleaner as well - neither seemed to make any difference at all where the right cylinder is concerned.

My only ideas right now are to run a leakdown test on both cylinders to try and rule out weak rings, or worn valves, or any of the other evil mechanical gremlins that make your compression fail - and then take another look at the carbs to make sure they're actually flowing air/gas.

Anything else we ought to be thinking about (other than the location of the nearest cliff)?

I would suspect fuel issues, even after the CARB cleaning.. My rule is, jets are never cleaned, too easily damaged, not cleaned as well you might think, and they are cheap.. So IMHO and what has worked best for me,, Jets are replaced, passages confirmed clear with brake clean, ect ect.
Has the bike ever run while in your hands/ or is this new to you bike..?

The fact it started to run, has some ignition drives me further to a fuel issue.

Leak down test would be a great idea just to rule out a holed piston, burned or busted or bent valve.

Make sure your trying to start it on a fresh battery, to the point of, jump it from a car battery so you know the motor is spinning as fast as possible and the ignition is getting full voltage while doing so.

I'd be willing to bet that the idle jets are still plugged. They have very, very tiny orifaces, plug up extremely easily and are a total ***** to get opened up. I soak them in carb cleaner for about an hour and then use a nylon bristle from a cheap paintbrush to open the passage. Repeat as many times as necessary to get them open. Don't try to use anything metal (like a torch tip cleaner) it will probably ream the oriface out larger and then you have an even worse problem.
Dane

How many miles are on the bike? If it's got spark with both plugs, then I'd go back to the carbs before I do a leak down test.

bronco78 said:

I would suspect fuel issues, even after the CARB cleaning.. My rule is, jets are never cleaned, too easily damaged, not cleaned as well you might think, and they are cheap.. So IMHO and what has worked best for me,, Jets are replaced, passages confirmed clear with brake clean, ect ect.
Has the bike ever run while in your hands/ or is this new to you bike..?

The fact it started to run, has some ignition drives me further to a fuel issue.

Leak down test would be a great idea just to rule out a holed piston, burned or busted or bent valve.

Make sure your trying to start it on a fresh battery, to the point of, jump it from a car battery so you know the motor is spinning as fast as possible and the ignition is getting full voltage while doing so.

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I've been running it off my jump pack (which is strong enough to turn over a diesel truck repeatedly), so I think the starter is moving as fast as the starter can run. This is actually my friend's bike. The VA has still not paid my tuition for last semester, so I'm living off the good graces of my family - no money for toys here.

We will definitely look at the carbs.

lddane said:

I'd be willing to bet that the idle jets are still plugged. They have very, very tiny orifaces, plug up extremely easily and are a total ***** to get opened up. I soak them in carb cleaner for about an hour and then use a nylon bristle from a cheap paintbrush to open the passage. Repeat as many times as necessary to get them open. Don't try to use anything metal (like a torch tip cleaner) it will probably ream the oriface out larger and then you have an even worse problem.
Dane

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Thanks.

DFW_Warrior said:

How many miles are on the bike? If it's got spark with both plugs, then I'd go back to the carbs before I do a leak down test.

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No idea how many miles are on it, the only reason I'm thinking leakdown is because it's not doing anything on the right cylinder - and the pressure it pushes with on the exhaust is way weaker on the right pipe than it is on the left pipe.

Seems my Dad reckons we're going to find a compression problem somewhere. Bent/burned valve, burnt rings, or a hole in a piston. We will go find out now.

Got the carbs off, poked out the passages and everything seems like it was still good and clean from the last time. The boots that connect the carbs to the heads were both wet with fuel from our previous attempts to start the bike as well. Fuel is definitely getting into the cylinders.

The compression gauge we bought did not come with a small enough adapter to be of any use on the cylinders, so I'm going to try and find the appropriate fittings to get that done at some point today. I did pull the plug out of the right cylinder, and it was wet with gas. Cleaned it off and tested it with the right coil and it's sparking a very weak spark from the ground tang to the bike frame - rather than a strong spark out of the center electrode across the gap. That ain't right so I'm off to get another plug.

Will update with any progress made.

Could be a bad coil as well.

And I'm just asking because I don't know, but do the pipes have an H pipe inline somewhere?

OK,, your doing a compression check, not a leak down... Keep in mind there is an automatic compression release at work on slow motor revolutions, like what you get from just using the starter.. what you get in readings will be of little value, .. SO consider it an YES/ NO deal.

DFW_Warrior said:

Could be a bad coil as well.

And I'm just asking because I don't know, but do the pipes have an H pipe inline somewhere?

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True enough, I've got new plugs to test now - if they don't work the coil starts to be a suspect. The pipes do have an H-pipe, and that's one of the reasons I want to actually check compression - pressure from the left cylinder could be making it out the right pipe.

bronco78 said:

OK,, your doing a compression check, not a leak down... Keep in mind there is an automatic compression release at work on slow motor revolutions, like what you get from just using the starter.. what you get in readings will be of little value, .. SO consider it an YES/ NO deal.

Click to expand...

Also true. Man it's been a while since I regularly used real tools to do things. I'd much rather do an actual leak-down test, but at this point I just want something of a baseline to GO/NO-GO this engine on. It's not even bike, but if she rumbles to life we're definitely going to have some fun with it.

Wish I could offer more help.... but I'm here and not there, and even when I'm there it's a long way from your there....... I assume you checked for spark in each cylinder by putting a plug in the cap grounding the plug and watching for a nice blue spark?

After several seconds of cranking.. are both plugs wet? drain fuel from both bowls?

Pull the valve cover, if you have a burned or otherwise bent/broken valve, the clearances will be WAY off as in VERY open or completely closed.

Valves ok, spark, cams turning with crank, good starter speed from a jump pack it has some compression upon check and roughly even side to side... .... I'd bet 99% it's carbs... I know, you've checked um... but they are testy things when all is not right.. Been doing this too long.... .. if your stuck at the end of the day.... with still no idea what is wrong.

Change the oil so you know it is not fuel contaminated, replace the spark plugs and jets, dump the gas in the tank and get some fresh stuff... I'd bet dollars to doughnuts it will start.

bronco78 said:

Wish I could offer more help.... but I'm here and not there, and even when I'm there it's a long way from your there....... I assume you checked for spark in each cylinder by putting a plug in the cap grounding the plug and watching for a nice blue spark?

After several seconds of cranking.. are both plugs wet? drain fuel from both bowls?

Pull the valve cover, if you have a burned or otherwise bent/broken valve, the clearances will be WAY off as in VERY open or completely closed.

Valves ok, spark, cams turning with crank, good starter speed from a jump pack it has some compression upon check and roughly even side to side... .... I'd bet 99% it's carbs... I know, you've checked um... but they are testy things when all is not right.. Been doing this too long.... .. if your stuck at the end of the day.... with still no idea what is wrong.

Change the oil so you know it is not fuel contaminated, replace the spark plugs and jets, dump the gas in the tank and get some fresh stuff... I'd bet dollars to doughnuts it will start.

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Any input is definitely appreciated. That's exactly how I checked spark. One of the plugs, the one that was actually in the cylinder, did not spark from the center electrode. Bought a new set of plugs to try out. I will test them for a healthy spark first - fresh out of the box - before I put them in the engine.

Several seconds of cranking results in both plugs being wet, as well as the intake tubes connecting the carbs to the head. I drained the carbs to pull them off earlier, but that's the only time I've done that. The gas did look a little cloudy in the catch cup.

I will pull the valve covers and see what I see. I haven't actually seen the valvetrain myself yet, just what my friend said he saw. Once I get eyes on, I will report back with what I see. If it all looks normal, I'll recommend we change out everything, clean the carbs again, replace the jets, etc. like you said, and give it a shot. Hopefully it works!

Ok,, for sure check for spark at both caps.. Truly the ignitions on that bike are very robust, not likely to be the cause.. but check.

DUMP that old gas,, all of it. run some clean out the bowl drains before you try starting it again.. and change the oil (I think you said you did that, if so, at least do a smell test of the new,, if you get a strong fuel smell, change again.. fuel gassing off contaminated oil can make starting difficult.

try some ether to see if it'll want to run

bronco78 said:

Ok,, for sure check for spark at both caps.. Truly the ignitions on that bike are very robust, not likely to be the cause.. but check.

DUMP that old gas,, all of it. run some clean out the bowl drains before you try starting it again.. and change the oil (I think you said you did that, if so, at least do a smell test of the new,, if you get a strong fuel smell, change again.. fuel gassing off contaminated oil can make starting difficult.

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Pulled the other plug, it was also soaked in gas. Tested both new plugs for spark and both are sparking strong and blue. Going out for dinner, will check the rest later tonight.

LOL, well it's 0345 here, And i start my road home in the morning,,errr,,, in a few hours,, so I'll catch the rest of the story in a week.

Good luck.

I've been on the "no school, no job" schedule lately. This puts me awake between about 1300 - 0500 or so. Enjoy the journey back. Hopefully you don't get to spend extended periods of time at BIAP or Ali Al-Salem. Somehow both trips home for me coincided with a spike in non-operational aircraft!

Seems the issue was spark plugs. Put the new plugs in, sprayed some starting fluid straight into the intake and she fired right up. Put the carbs and gas tank back on, same thing. Started pretty easily, and here's the result:

Sounds like my lawn mower, though.

Exhaust pipe off maybe?

Wow, that is a strange sounding Ninja 250. I am with Chuck though, I didn't know Briggs made the motors for the small Ninjas.

Kinda sounds like somebodys Strom.

Good news, Anthony!!!! Time to ride!

I have an '04 Ninja 250 as well. It's tough to tell from the video, the bike maybe sounds a little odd, but it's not all that different from mine. These engines are clattery at idle, but smooth out and quiet down above 3K RPM.

How confident are you the valves were set correctly?

Have you verified the cam timing? The bike uses threaded adjusters, so the cams don't come out to adjust lash. But unless you know the ownership history, it's worth checking.

Cam chain rattle is common on this engine. You can reset the adjuster, or back if off until you hear a single click, then tighten it back up. Google up some of the ninjette FAQs for more info.

How does it ride now? One good cylinder makes ~15HP, so it should manage 50+ MPH even then.

I'm wondering if the exhaust system is somehow plugged up...

In the video it was mentioned that you don't have the 2 stroke style smoke yet, just a thought but you do know that this a a 4 stroke correct. And it sounds to me like it has jumped time, and possibly piston hitting valves. I know cars can do this and I'm sure some bikes maybe also.

On-Off said:

...it sounds to me like it has jumped time, and possibly piston hitting valves.

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I was gonna suggest that, too, but I don't have enough EX250 knowledge to know whether or not they ever get that clacky under normal running conditions. It really does sound like an out-of-phase motor to me.

Gilk51 said:

Sounds like my lawn mower, though.

Exhaust pipe off maybe?

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No signs of an exhaust leak (though finding one of those can be like finding a needle in a haystack).

DFW_Warrior said:

Wow, that is a strange sounding Ninja 250. I am with Chuck though, I didn't know Briggs made the motors for the small Ninjas.

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Yeah, the mic on my G9 isn't the greatest in the world and makes the painful knock sound a lot more like an annoying tick. In person it literally sounds like the rods are trying to free themselves from the crank.

db said:

Good news, Anthony!!!! Time to ride!

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I definitely do not want an engine making those noises between my legs!

jcyuhn said:

I have an '04 Ninja 250 as well. It's tough to tell from the video, the bike maybe sounds a little odd, but it's not all that different from mine. These engines are clattery at idle, but smooth out and quiet down above 3K RPM.

How confident are you the valves were set correctly?

Have you verified the cam timing? The bike uses threaded adjusters, so the cams don't come out to adjust lash. But unless you know the ownership history, it's worth checking.

Cam chain rattle is common on this engine. You can reset the adjuster, or back if off until you hear a single click, then tighten it back up. Google up some of the ninjette FAQs for more info.

How does it ride now? One good cylinder makes ~15HP, so it should manage 50+ MPH even then.

I'm wondering if the exhaust system is somehow plugged up...

Click to expand...

Colby, the owner, had gone through the whole ninja250info FAQ thing before he brought it over and we went through it again to double check when we brought it to my place. Since he'd done everything once, I did it all the second time. The valves are in spec, and the cams line up the way the FAQs say they should line up. Cam chain has been reset as well.

Neither of us were willing to throw a leg over it, so I'm not sure how it rides. There *is* a sound of perhaps a leak in one of the cans, but it is vastly overpowered by what I'm guessing is rod knock.

What I'd like to do from here is run it up to temperature again (assuming it doesn't seize first), let the oil drain down and dump it. Right now, I'd bet a shiny nickel I'll find metal in that oil.

On-Off said:

In the video it was mentioned that you don't have the 2 stroke style smoke yet, just a thought but you do know that this a a 4 stroke correct. And it sounds to me like it has jumped time, and possibly piston hitting valves. I know cars can do this and I'm sure some bikes maybe also.

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Heh, yeah I know it's a 4-stroke. Looking down through the spark plugs holes earlier revealed quite a lot of garbage *on top* of the pistons. A little light oil got squirted in and we bumped the engine over to try and "clean" things up a bit. When we started it, it took a while for said oil to burn off.. and put a nice heavy coat of smoke down most of my street.