Engine struggling for first few seconds (Ninja 250)

rat_race

Hi,

Have a 2010 Ninja 250, with 17k miles. Thesedays, when I start it from cold & idle, the revs start off very low, as if it is struggling. The bike always starts fine though -- only need to press the starter button for a second, as normal. But once started it almost sounds like it's only working off one cylinder. I give it some revs (in neutral) to get things moving, and it recovers.

But then when I initially drive it a few feet, if I was to brake and stop (with clutch in, or in neutral), it would nearly cut out. Usually doesn't, but definitely isn't normal for it to drop the revs that low. It splutters. If I keep it going without stopping, it's fine.

If I was to turn the engine off in the first minute or two after the initial start, then starting it again is rather difficult (needing to press the starter button for few seconds while opening throttle). It just doesn't sound healthy.

This is only ever for the first couple of minutes. Once she warms up she is fine. So it's either to do with the cold or oil not getting pumped around properly.

Any ideas on what's causing this? It's not a big problem, I'm more curious than anything -- and also don't wanna do any unnecessary damage.

Notes:
- valves never checked (have it booked for couple of weeks though)
- oil needs change (changed along with plugs 5-6k miles ago)
- air filter needs change as per maintenance schedule (have one, will replace)
- will be changing plugs with oil very soon (myself)



Cheers,
C

Wonda-Boy

Sounds like there is water (condensation) down one of the plug leads. Happened to me about 3 weeks ago with the very damp weather we are having if a bike covered up with get it. Take out both leads and spray a bit of WD40 down the tubes, and around the rubber seals (it will stop them perishing anyway)

Its deffo something along them lines.....I would say.

rat_race

Wonda-Boy wrote: »

Sounds like there is water (condensation) down one of the plug leads. Happened to me about 3 weeks ago with the very damp weather we are having if a bike covered up with get it. Take out both leads and spray a bit of WD40 down the tubes, and around the rubber seals (it will stop them perishing anyway)

Its deffo something along them lines.....I would say.

I always felt it was the plugs, for some reason...

Thanks for the advice. I will do this with my oil change in the next few days...

So it's okay to get WD40 in/around the spark plugs and tube?

Seanbass

I used to have that bike and as far as i know there is an automatic choke that stays active for the first few minutes until it warms up, if you try rev or drive the bike while the choke is still active the engine will adjust to the revs with the effect that when you stop revving the engine will nearly cut out.

is this a new problem?
it sounds similar to this though, its the same on my zx6r, I have to wait for the temp to show up on my dash for about five mins or so..

rat_race

Seanbass wrote: »

I used to have that bike and as far as i know there is an automatic choke that stays active for the first few minutes until it warms up, if you try rev or drive the bike while the choke is still active the engine will adjust to the revs with the effect that when you stop revving the engine will nearly cut out.

is this a new problem?
it sounds similar to this though, its the same on my zx6r, I have to wait for the temp to show up on my dash for about five mins or so..

Hi -- I knew about that choke, yep. While doing its stuff, the engine might "idle" at 4-5k revs for a few minutes after an initial start and then gradually stabilise to 1.5k. That's normal/expected.

But you are meant to drive/rev the bike right away, there is no need to wait for it to warm up. It's a fuel injected bike and even the manual says to drive immediately and not wait (although, I prefer to wait 45 seconds or so)...

What you described could be related to this problem (maybe even the cause), but this never used to happen before, at least not to the point where it is noticable/a problem.

Thanks for the help.

CJhaughey

rat_race wrote: »

But you are meant to drive/rev the bike right away, there is no need to wait for it to warm up. It's a fuel injected bike and even the manual says to drive immediately and not wait (although, I prefer to wait 45 seconds or so)...

Fuel injection doesn't mean the engine warms up instantly though.
The oil is thick in this weather and it takes some time to make its way around the engine through all the little galleries.
I would always warm an engine up properly give it a minute or two while you are getting your gear on.
It won't do it any harm at all to fast idle for a few minutes.
Its because of emissions requirements that you are supposed to drive off straight away, not because its good for the engine.

rat_race

CJhaughey wrote: »

Fuel injection doesn't mean the engine warms up instantly though.
The oil is thick in this weather and it takes some time to make its way around the engine through all the little galleries.
I would always warm an engine up properly give it a minute or two while you are getting your gear on.
It won't do it any harm at all to fast idle for a few minutes.
Its because of emissions requirements that you are supposed to drive off straight away, not because its good for the engine.

Yeah, I fully agree...this is what I usually try to do. Usually I turn it on while opening gate/putting on helmet/gloves, etc, and then give it a few gentle-ish revs before pulling off. Doesn't seem to make a difference in term of the almost-cutting-out-issue, but as I mentioned earlier: when the bike is fully warm it runs perfectly, so it does seem related. I just don't recall this the previous winter ...

Going to service everything next week...maybe an oil change and new plugs will help things.

Seanbass

hmm strange then,
I've noticed the same thing with all newish kawasaki bikes I've driven, generally happens to me if i try drive off too soon before she's warmed up fully, as I said It goes away once warmed up.
it almost and sometimes does cut out if i try drive it straight away from a cold start so I thought it might be your problem.
but sure get it checked with your service man.

have to say, I don't remember the manuals saying that though, thought they said to allow the bike sufficient time to warm up i.e. 5 minutes etc.
ill have a root in mine out of curiosity..

rat_race

Seanbass wrote: »

hmm strange then,
I've noticed the same thing with all newish kawasaki bikes I've driven, generally happens to me if i try drive off too soon before she's warmed up fully, as I said It goes away once warmed up.
it almost and sometimes does cut out if i try drive it straight away from a cold start so I thought it might be your problem.
but sure get it checked with your service man.

have to say, I don't remember the manuals saying that though, thought they said to allow the bike sufficient time to warm up i.e. 5 minutes etc.
ill have a root in mine out of curiosity..

Well I am glad to hear that it's common. Might be normal/acceptable...

Wonda-Boy

rat_race wrote: »

I always felt it was the plugs, for some reason...

Thanks for the advice. I will do this with my oil change in the next few days...

So it's okay to get WD40 in/around the spark plugs and tube?

Perfectly okay for the WD40 around the plugs and and leads...it will dissipate any water around the plug and help the leads last longer.

spiggotpaddy

Going to service everything next week...maybe an oil change and new plugs will help things.[/QUOTE]

There's no point in trouble shooting untill after your tune-up.

rat_race

Just an update on this, to anyone else who has a similar issue.

I adjusted the valves, myself. The bike appears to be running much better now...the revs never drop below what idle should be. I also noticed the at the air out of the exhaust is much more powerful than it was before...not sure if that's in my head, or it is down to the adjustments.

My measurements showed that all valves were too tight: exhaust and intake. I had to adjust every single valve.

I can also hear the valves chattering a bit, something I do not remember from before. Where possible, I adjusted the valves to be on the loose side (within spec of course), as it's like they'll get tight again, as opposed to looser (I hope).