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How Strong Should The Spark Be?


ticket2ride
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Can anybody suggest what sort of spark I should be looking for when manually turning over?

I'm trying to figure if there could be an electrical issue with the coil/stator pack...

When pushing slowly with the kickstart - we don't get any spark?...when we push a bit quicker a spark starts to appear.....it's not hugely bright but there's something there?

Should we be getting a strong spark even when pushing slowly though the stroke?

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What bike is it? if its cdi the spark always looks weak! ie white, if its points ignition it should be a fat blue spark! if your turning the kickstart slowly what do you expect? i would have thought the spark strengh would be at its strongest when the kickstarts kicked over as you would do it when trying to start the bike!

:D

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There's no hard and fast rule for the spark, but if the spark is a blue colour, as opposed to an orange, then the blue spark is more likley to fire the charge, are you plugging the spark plug into the plug cap and earthing on the cylinder head, or are you unscrewing the plug cap and get a spark directly from the ht lead., as either way can produce different results.

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...cheers....

...it's a 2004 315 - so CDI..!

I've opened the plug gap a bit and there's a fair spark there when I kick it over....I leave the plug in and rest it against the cylinder head

I'm trying to narrow down the plug foul issue - thought it may be a stator/coil problem...

so far, I've checked the following:

air leaks

carb cleanliness, jetting,

kill switch

stator condition / water behind flywheel cover

Everything seems okay - it's just dry fouling plugs after about 30mins of use, then starting to misfire due to the plugs being so badly fouled....

Any other ideas?

Edited by ticket2ride
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Please excuse my ignorance, but what exactly is 'dry fouling'. Surely either the spark plug is not working due to the insulation surrounding the middle electrode braking down, due to a contaminant or it's useable. Dry fouling is a new expression to me, can you explain.

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Hello,

Yes - bascially, when removing the plug the electrode, threaded area etc is completely black - not wet oil residue from an incorrect mixture but very dry and sooty, 100% covered infact!

Aparently, such plug fouling is referred to as dry fouling or Carbon fouling and is caused by the mixutre running too rich...

As the mxiture/jetting is how it's supposed to be, and we can't find an air flow blockage...we're starting to consider a spark issue....weak ignition...

Difficulty is knowing whether to start at the coil, stator or CDI.....and how to test each!!

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I think your best bet, is to explain to the readership exactly what the symptons are. We know the end result is a super rich/chocked spark plug, but you haven't exactly explained what the engine does in the 30mins, before the spark plug expires. Are you replacing the damaged plug everytime, or just cleaning and replacing. I would have thought the engine would have gone into 4 stroking before stopping maybe ! Does the engine idle properly. I personally would explain the symptons and I'm sure somebody out there with a similar bike has had a similar problem.

Edited by ask greeves
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As the mxiture/jetting is how it's supposed to be, and we can't find an air flow blockage...we're starting to consider a spark issue....weak ignition...

Difficulty is knowing whether to start at the coil, stator or CDI.....and how to test each!!

Since it does run for a while, I'd suggest it's not a major electrical prob.

Try a *new* BPR5ES and take out the airfilter. Run for 5-10 mins & then stop & pull your plug. Still black & sooty? Could it be you have over oiled the filter?

Since you have had the floatbowl off to check the jets right? 2nd possible I can think of is the pin for the float is not in correctly & is holding the float down, meaning nothing is stopping the fuel flow. If you run the motor @ high revs rather than idling is the plug better?

On same lines it could be the needle & seat is not shutting of, if this is the case new one might be best bet.

HTH

Edited by cadman
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..thanks for the reply greeves,

...the bike tends to fire up from cold first kick, no problems....

..it then runs well, idle's and warms up no problems....

..after about 20 - 30mins it starts to loose it's idle, cutting out when off the throttle.

Shortly after, it starts to run erratically, misfires a bit, bogs down a bit off the bottom, becomes a bit poppy...still not idling all this time...when it cuts out, it starts again on about the 2nd kick, but just about fires into life...

At this point - I've been changing the plug for a new one, it runs okay again for a short while, then, the same symptoms arise and it's new plug time again!

Interestingly - I thought at one point the air screw was too far in, so I wound it out quite a bit.....the effects were expected in that the bike (as well as the misfires etc) started to run a bit zingy (too lean a mixture) with open throttle...leading to the conclusion as advised that the current jet/air screw settings are correct....

so, my current mindset is a low rpm sparking problem?

checking another new plug last night, when kicking over showed a good strong spark, but....who knows how the spark is when the engine is running at low rpm...

...thanks for the adivce Cadman....

..the BR5ES - that's a slightly hotter plug isn't it?

I'll give that a try later...

Over oiled the filter?....interesting.....I do put a bit of oil on and squeeze it in a little.....not too much mind.....

What size plug gap do you run with?.....0.7?

I've also meshed off the holes in the mudguard, but there's still plenty of airflow through there...

Scratching my head a lot at the moment.....definitely seems to be a low rpm thing....

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>..the BR5ES - that's a slightly hotter plug isn't it?

Yep only one that worked for me, but if have a 6 then that would be OK.

Either a 5 ot 6 won't cause what your seeing.

> Over oiled the filter?....interesting.....I do put a bit of oil on and squeeze it in a little.....not too much mind.....

As I sugested, take it out for 10 mins & run the bike with a new (5 or 6) plug, then check the colour.

This test will give others a better idea of "next step" in testing.

What size plug gap do you run with?.....0.7?

> fine tuning, unimportant at this point. But per the manual.

>Scratching my head a lot at the moment.....definitely seems to be a low rpm thing....

Try the filter idea, if no good take the the float bowl cover off, turn on your fuel tap, & check that the float does stop the flow when you lift it *lightly*

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needle and seat?

I'm not too sure what you mean by that?

The carb slide is travelling fully - needle moving down as it should....needle clip position is 2nd up from the bottom...as recommended by the guys at Sandifords....

I'll have a look at the float movement too - make sure there are no restrictions.....

I hope it's not an electrical fault - although, I have heard about some CDI/coil/stator problems on the 315....

This ones a 2004 and has done nothing at all really....but, you never know with electrical components!!

Thanks...

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yeah sound's electrical from here.

once the engine get's hot strange thing's can happen if there's an electrical breakdown, abit like what your experiancing.

when your stopping to change your plug the engine is cooling down and that's why it start's up ok again until it get's hot again.

Edited by bilco
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