honda crf100 non start

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honda crf100 non start

Postby antthecat » Mon Oct 08, 2012 4:13 pm

hi all, got the above bike in, no spark start issue.

no pulse to coil, cdi unit has no output but has a signal to the cdi unit and kill switch and key switch prove good.

i have uploaded waveforms, waveform 1 has probed coil feed (permanent earth to coil so im presuming switched feed) on ch.a and one side of the crank sensor (blue/yellow wire if its helpful),
honda pit bike no start 1.psdata
(545.58 KiB) Downloaded 214 times


waveform 2 has same coil feed and other side of crank signal (black/red wire),
honda pit bike no start 2.psdata
(776.44 KiB) Downloaded 205 times


looking at pick up, it only has one raised notch on pulley. see photo below
crank pickup.bmp


has any bike guru's seen this fault before, btw it has had a new cdi unit fitted also.

cheers

Ant
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Re: honda crf100 non start

Postby Avdr » Mon Oct 08, 2012 5:57 pm

On the second file, what are we actually looking at? I'm guessing it represents two revolutions of the engine - or atleast two events where the notch passed the pick up?

Seems that taking a time differential from the beginning of first event to the beginning of the second, correlates to approx 40rpm.

And that individual fluctuations within an event represent over 2500rpm.

40 seems slow, and 2500 is clearly too high. So what is causing the minor fluctuations within each event, surely that should be a clear graph, with a start point as the leading edge of the notch comes by the sensor, a consistant line as the arc passes by, and a drop as the trailing edge leaves the sensor window.

How is the cdi powered, by an exciter coil on the stator plate or battery?

EDIT: the first file once zoomed in looks more informative. That shows the pick up as working.

I can tell you, I once had odd problems with an aprilia rs125. It kept wrecking coils - literally shorting them out internally. After the second replacement coil I began to suspect the cdi. Changed cdi and fitted a new coil and its been fine since.

Have you tested the coil's resistance?
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Re: honda crf100 non start

Postby antthecat » Mon Oct 08, 2012 6:44 pm

Each ripple is as I'm kicking it over, can't quote the rpm, I think the first waveform is the business one but thought I better show what's happening out of the black/red wire as it might be relevant.
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Re: honda crf100 non start

Postby antthecat » Mon Oct 08, 2012 10:18 pm

Last post was rushed, I have not tested the resistance of the coil, will get the meter on it as and when workshop is quiet, no battery, voltage is generated by stator as far as I can tell.

This has had a cdi unit but unsure of quality as supplied by customer.

Customer has also brought in a 90cc quad with a c90 engine, may use a similar setup and as its running may be useful for info, can't muck about on the quad yet as chain keeps falling off.

Cheers for the help

Ant
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