weak spark? nc23

[wig]

All long last with my bike through an mot, im back to using it and jump starting again.
It just seems to not be able to produce a spark when trying to start.
To bump start, it will almost start as soon as you jump on an release the clutch.
Is there a capacitor or something I can fit to store some charge so the starter motor doesnt eat it all away?

[CMSMJ1]

Have you checked the health of your battery and charging system?

Check the Volts on the battery with it turned off and then test it when you try and start it.

Once it is running, check voltage at 5000 revs.

Let us know..

[wig]

I will have a look at the voltage soon when i can get my hands on a voltmeter that i can trust.lol.
the thing is, even though it does not start of fire, the starter motor is spinning the engine over at a rediculous speed. and can do it for quite some time before the batt starts to die.

[natehog]

Is the starter motor actually turning the engine over or just spinning freely? Sounds like a starter motor/starter clutch issue if the bike bumps OK and the battery turns the motor over no problem. A weak charging system would mean that there isn't enough power to turn the starter motor over and you say it's spinning fast.
Nate

[wig]

the starter motor is turning the engine over, as if you turn the throttle, you can hear the change in sound from the exhaust. It turns over realy fast and it is the same even with a spare batt.
Its just that it doesnt start, unless its realy cold. then there is not normally a problem.

[natehog]

So are you saying the bike wont start when it's hot unless you jump it?

[wig]

It will start when warm, its just that it goes through phases where it doesnt start well, and most of them are all when it is hot or warm

[natehog]

Check the Choke cable, make sure the mechanism isn't jamming partially open (to test this pull the end of the choke actuation rail open to see if the revs change - you can find this on the side of the carb by following the choke cable).

Have you added a free-flowing airfilter/exhaust? Have you changed anything at all with the bike? Poor fuelling can be a cause of poor hot starting, I had a NC29 with that problem.

[wig]

ok ill have to have a look.
i cleaned the carbs and one of the needle height adjuster was seized into the carbs.
I removed the others and cleaned them, the rubber o rings were a bit worn on them, as tiny as they are!
they were also screwed in more than they should have been, so now all the others are the correct number of turns would out apart from one.
i rode home yesterday, got fuel. went to start it, and it didnt start. so i waited for a few seconds, and tried again, and it started straight away! very confusing.

cheers for the advice you lot.

[natehog]

Try checking the HT leads, spark plug condition and electrode gaps - failing that have a look at the engine cutout switch - make sure it's not giving an intermittent fault.

This does sound like a strange one! Sorry I can't be more specific with my solutions.
Nate