Bike won't start... sometimes

[acook3323]

My 05 ninja 250 starts every once and a while. Once I get it running and shut it off it has a hard time starting up again. Carbs are definitely clean, recent oil change, new spark plugs. Anyone have any ideas?

[jkv45]

Originally Posted by acook3323

My 05 ninja 250 starts every once and a while. Once I get it running and shut it off it has a hard time starting up again. Carbs are definitely clean, recent oil change, new spark plugs. Anyone have any ideas?

Are the carbs adjusted and synced?

How old is the gas?

[acook3323]

Not very old and everything is synced. Didn't change anything since it was running last time

[Z1R rider]

Originally Posted by acook3323

Not very old and everything is synced. Didn't change anything since it was running last time

How long ago are we talking?

[acook3323]

Couple weeks maybe a month

[Triple Jim]

The first thing I'd do is see if I have spark when it won't start.

[Z1R rider]

Like Jim says, check your spark. Or maybe a vacuum leak, cracked hose, or cracked intake (the rubber manifold between carbs and engine), I've had them split under the clamps closest to the engine, making it hard to start and run poorly at low engine speeds. When I found a crack under the clamp I took the clamp out of the way and wrapped electrical tape around a couple times then replaced the clamp over it.

[acook3323]

I know I have spark. The vacuum leak is a good idea!

[acook3323]

Could it possibly be a glogged air filter?

[Z1R rider]

I suppose, but it would have to be REALLY bad, (like a mouse nest, guess how I know that) it would be like the choke on all the time.

PS: even with the mouse nest it would start and idle fine.

[Triple Jim]

It takes only a minute to look at the filter and see if it's clogged.

[acook3323]

What about mixture screws? Could my mixture be off too much?

[jkv45]

Originally Posted by acook3323

What about mixture screws? Could my mixture be off too much?

What are they set at now?

2.5 turns out is the standard baseline, and should be very close.

Fresh gas is a must. If there's any question you should completely drain the tank and floatbowls. Gas goes bad even if it's not that old. It's a big variable, and the first thing I always consider when a problem arises.

[acook3323]

Put in fresh gas. Tightened the boots and checked the air filter and now it won't even start.

[Triple Jim]

And you definitely have spark, right? If so, I'd say your pilot circuits are clogged.

[jkv45]

Originally Posted by acook3323

Put in fresh gas. Tightened the boots and checked the air filter and now it won't even start.

How is the battery? When you drain everything it takes some cranking time to allow the fuel to flow, so if you haven't cranked a while you may not have gas to the carbs yet.

That drains a battery pretty quickly, so it will need most likely need a charge.

If you still get nothing, pull the plug wires and check for a spark. If you have spark, you can remove the air filter and give the carbs a quick shot of starter fluid. If it fires up momentarily it tells you for sure you don't have fuel.

Just don't use much. It will pop over from just a quick shot.

[acook3323]

Sprayed a tiny bit and it started! I checked the float bowl and there is fuel in them. Checked the jets and cleaned the whole carb. Still nothing

[Triple Jim]

My bet is on clogged pilot circuits, no matter how many times you say the carbs are clean.

[Z1R rider]

^^ what he said^^, not just the jets but the passages inside the carb also and maybe the enriching (choke) circuit also.

[acook3323]

I pulled the carb and the pilot jets and sprayed cleaner through the passages. The carb cleaner went through no problem so i dont think they are clogged

[jkv45]

How about the idle mixture passages? Did you remove the screws and make sure the passages are clear?

Have you confirmed the idle mixture screws have o-rings in good shape? They can tear and block the passage. The screws should be set to 2.5 turns out as a baseline.

You have confirmed that the issue is with the carbs/fuel, so that's a good start to solving the problem.

[acook3323]

Pulled everything again. One mixture screw is missing an outing. Would that cause the problem? All the passages are clear. I can spray through all of them no problem

[jkv45]

Originally Posted by acook3323

Pulled everything again. One mixture screw is missing an outing. Would that cause the problem? All the passages are clear. I can spray through all of them no problem

Make sure the o-ring isn't stuck up inside the hole.

Yes - not having an o-ring would cause problems.

It needs to go together like this - https://faq.ninja250.org/images/9/9a/BC_cleaning_4.jpg

[acook3323]

What kind of problems would I see. I don't see washers on either or an o ring on 1 and can't see them in the hole

[Z1R rider]

the O-rings seal the needles so you don't have a vacuum leak, and the washers protect the O-rings from the springs.

[acook3323]

Do I have to get the o ring and washer from the dealer or can you get them from like home depot or a place like that?

[ducatiman]

Inspect and probe the pilot screw orifice carefully...possible they are still in there?????

I keep orings and washers in stock, standard procedure within my carb service.
There are metric, extremely tiny...doubtful you'll find local.

PM me if you need....but make sure they are, in fact, MIA first!

[jkv45]

Originally Posted by acook3323

What kind of problems would I see. I don't see washers on either or an o ring on 1 and can't see them in the hole

The kind of problems you have.

Get the correct washers and o-rings, set the screws to 2.5 turns out, and report back.

[acook3323]

Would these missing be the cause to my problem?

[jkv45]

Originally Posted by acook3323

Would these missing be the cause to my problem?

Most likely.

[ducatiman]

The Keihin factory chose to install the orings to seal that section of the pilot chamber from introduction of false air....thus assuring precise pilot screw metering. This, assuming the rest of the pilot circuit is, in fact, clear.

Will this cure your hard starting issue? Likely a contributing factor...when critical parts are found missing, its imperative to correct...what may seem trivial (the insignificant, tiny little oring) is in fact, quite important in the role that it plays.

Troubleshooting includes a process of elimination.

As JKV correctly posted....replace the parts (washers too) ...set the screws at 2.5 starting position. You should then fine tune each side and reaccess starting situation.

[acook3323]

I have been talking to a friend of mine and he says the rings could be shot. Is that a possibility or would it not start at all even with a tiny bit of starting fluid?

[Triple Jim]

An easy to do compression test will tell you the condition of your rings.

[DannoXYZ]

If rings are shot, it won't run with starting-fluid. Just fact that it runs on starting-fluid shows you're not getting fuel out of carb into engine.

[acook3323]

Can get it to start on starting fluid but only will stay started on choke. But can't really rev it at all

[ducatiman]

The thread has discussed carb cleaning, carb synch fresh fuel, spark plugs, vac leaks, air filter, pilot screws with missing orings, battery, plug wires, jets , compression testing.

You've summarily proclaimed everything is ok....but fact remains, it will run temporarily only using starting fluid ....indicative of internal carb issues...consistently suggested by 3 or 4 of us within the thread.