Ongoing 250R problem: starting issues

Should make this a sticky. Just did another one yesturday. Same thing every time.

Old 03-31-2010, 03:01 PM #18
kneedragger88
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Join Date: Jun 2005
Posts: 2,830

Default Re: '09 Ninja 250 - Not Starting
I store about 30 of these every year. End of season I drain the gas, run the bike 10 min on stabil (d) gas then drain the tanks. Put them away with the batterys on charge and every spring about 1 in 10 wont run.
Its ALWAYS the same thing. Somehow the teenie tiny pilot jets plug up and dont allow any fuel through. I would put money on this being your problem.
To test my theory go get a propane torch like you would use for plumbing. Just turn on the propane NO FLAME and hold to your airbox intake. On that bike right side there are three bolts holding on the cover. Put the torch bleeding raw propane into the intake and try again. Bet it starts!
Dont worry the propane will do no harm to your engine unlike over use of ether (quick start). If I prove out correct pull the carbs and blow out the pilots. re-assemble and she will run good as new.
If you can get it pm me I can come get it running. I work cheap.

Good thread. The underlying cause and PERMANENT fix ought to be mentioned, too.

The issue is that the low speed carburetion on these engines is set EXTREMELY lean, for emissions reasons. The problem is that if anything is the slightest bit out of spec (or if the fuel in the carb has sat around for the slightest bit too long), it goes too lean to fire, and then ... no start.

To fix this, the carburetors need to come apart. Replace the pilot (slow) jets with one or two sizes bigger and put one or two washers underneath the needle in each carburetor. It may take minor experimenting to get it right, but once sorted out, they start and run a lot better.

I don't have the part numbers of the required slow jets on hand - maybe someone will do this and chime in. You can get the appropriate shims and replacement slow jets very cheaply from Winner's Circle.
http://www.winnerscirclecanada.com/index.php

It can also be added that before you go shimming needles, get those pilot screws adjusted PROPERLY as they are set very lean from factory.

The Ninja 250 FAQ covers this, and the process is simple and can sorta be done on the bike.

***NOTE: All model years of the 250 and 500 can benefit from this.***

1. Drill out the pilot plugs located at the bottom of the carbs.
2. Factory setting is around 1.5 turns out. Not enough.
3. Screw both pilot screws/fuel mixture screws in
4. Back both out 2-2.5 turns.

BOTH carbs must be exact. Paint a small dot on the screw driver if necessary so that they are consistent.

If you're still having problems, shimming the needles is the way to go, but start with what is cheapest, easiest and makes sense first.

Quote:

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Originally Posted by toastywaffles

It can also be added that before you go shimming needles, get those pilot screws adjusted PROPERLY as they are set very lean from factory.

The Ninja 250 FAQ covers this, and the process is simple and can sorta be done on the bike.

***NOTE: All model years of the 250 and 500 can benefit from this.***

1. Drill out the pilot plugs located at the bottom of the carbs.
2. Factory setting is around 1.5 turns out. Not enough.
3. Screw both pilot screws/fuel mixture screws in
4. Back both out 2-2.5 turns.

BOTH carbs must be exact. Paint a small dot on the screw driver if necessary so that they are consistent.

If you're still having problems, shimming the needles is the way to go, but start with what is cheapest, easiest and makes sense first.

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What would it cost for someone to do all this for me?, I am not that Mechanically sound :P. I change my oil and plugs thats about it for me :P.

2009 ninja 250, always hesitates on tip in.

removed idle screw plugs and found left side set at 2 3/4 turns, right side set at 1 7/8 turns,
set both sides to 2 3/4 turns and synched carbs, problem solved, hesitation eliminated.
thought id share.

cheers

If you can fix it by idle mixture screw adjustment, you are one of the lucky ones. Obviously, it's the first thing to try since it costs $0. Seems to vary a little from one bike to the next. Had to deal with one a while back where a shop had set the idle mixture screws 6 (!) turns out to try to fix this, and it didn't fix it. Having the mixture screws more than about 3 turns open doesn't make them flow any more fuel. Nothing short of new (bigger) slow jets and a washer under the needles (and the mixture screws reset to 2 turns out) fixed that one.

Quote:

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Originally Posted by Favre

What would it cost for someone to do all this for me?, I am not that Mechanically sound :P. I change my oil and plugs thats about it for me :P.

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did you ever get this done? my bike is running fine now, but i wouldnt mind a referral if i'm expected to have the same problem

Quote:

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Originally Posted by joyinc

did you ever get this done? my bike is running fine now, but i wouldnt mind a referral if i'm expected to have the same problem

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Read the op.. The best person for the job :cool:

Quote:

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Originally Posted by FiReSTaRT

Read the op.. The best person for the job :cool:

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oh i was just askin cause i live closer to favre... I'm assuming the OP is in toronto? not that it matters yet lol, my 250 is running just fine :)

Anyone care to chime in as to the exact size of the slow jets that need to be installed to make the bike run so much better?

Was wondering if the bike is flooded how to fix it?

If it is FLOODED (too much fuel) - Choke off, hold the throttle wide open, and crank the engine. If it catches, then back off the throttle immediately to avoid bouncing it off redline.

If it does not show any sign of firing at all after cranking for 5 or 6 seconds (no more) when doing this then either (A) you have fouled the spark plugs with raw fuel, in which case the only option is to replace them with new - and they will be quite obviously wet with fuel, or (B) the real problem is something else.

Quote:

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Originally Posted by Brian P

If it is FLOODED (too much fuel) - Choke off, hold the throttle wide open, and crank the engine. If it catches, then back off the throttle immediately to avoid bouncing it off redline.

If it does not show any sign of firing at all after cranking for 5 or 6 seconds (no more) when doing this then either (A) you have fouled the spark plugs with raw fuel, in which case the only option is to replace them with new - and they will be quite obviously wet with fuel, or (B) the real problem is something else.

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Can't you just crank the engine with:
Throttle closed
Choke closed?

That would prevent further gas from getting in the engine.

Quote:

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Originally Posted by RockerGuy

Can't you just crank the engine with:
Throttle closed
Choke closed?

That would prevent further gas from getting in the engine.

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No it won't. Intake vacuum from the closed throttle while cranking will pull additional fuel in through the idling circuits. If the engine is already flooded (too much fuel in there already) you don't want that.

An open throttle at starter-motor-cranking speeds will prevent any significant intake manifold vacuum which will prevent additional fuel from coming in through the idle circuit, and the airflow through the main venturi is too low at starter-motor-cranking speeds to draw much fuel through that circuit, either. What I described is the standard practice for clearing a flooded engine.

Some fuel injected engines emulate this. Wide open throttle at engine-cranking speed shuts off the injectors. The situation is less likely to occur with a fuel injected engine, but it's possible.

way to go half year old thread

Quote:

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Originally Posted by Brian P

No it won't. Intake vacuum from the closed throttle while cranking will pull additional fuel in through the idling circuits. If the engine is already flooded (too much fuel in there already) you don't want that.

An open throttle at starter-motor-cranking speeds will prevent any significant intake manifold vacuum which will prevent additional fuel from coming in through the idle circuit, and the airflow through the main venturi is too low at starter-motor-cranking speeds to draw much fuel through that circuit, either. What I described is the standard practice for clearing a flooded engine.

Some fuel injected engines emulate this. Wide open throttle at engine-cranking speed shuts off the injectors. The situation is less likely to occur with a fuel injected engine, but it's possible.

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Thanks for clarifying that.

I'll have to refer to carb diagrams to fully understand that.

Hey Ken I think I might be having the same issue...I will try changing the spark plugs as recommended to me in the forums and see if tht does it.

Just wanted to share you dont have to use a propane torch if you dont have one. You can spray just about anything into the engine. Carb cleaner works great too.