Author Topic: Condenser Missing?  (Read 3396 times)

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Hancock

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Re: Condenser Missing?
« Reply #15 on: 30 June, 2018, 12:55:48 »
Here’s a photo with new condenser. I tried the above with plug out and opening points. As you said difficult to tell wether spark is better or not. How can a condenser be wrong polarity?.and I presume it’s correctly fitted.

JulianS

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Re: Condenser Missing?
« Reply #16 on: 30 June, 2018, 14:08:48 »
Your very first photo seems to show a black sleeved wire connected to the distrubutor (this is the one I though might be connected to a remote condenser). This wire is not shown in the second photo??

Running without condenser would result in burnt points - are they in good condition?

AWJDThumper

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Re: Condenser Missing?
« Reply #17 on: 30 June, 2018, 15:39:16 »
Sorry - my use of English wasn't clear enough! I meant that without the capacitor, you might find it difficult to see the spark. The difference with and without the capacitor should be totally obvious - in the former case, you will see (and hear) a strong bright blue spark; in the latter case, you might struggle to see the very weak spark. If you can't see a difference then it suggests the capacitor is not doing it's job.

This assumes that the coil is working correctly. If there is a problem with the primary winding (eg partially shorted), it might not generate the correct HT voltage across the spark plug. If you have a digital voltmeter, you can measure the resistance of both the primary and secondary windings. If ok, they should be about 2 Ohms and 10,1000 Ohms, respectively.

The capacitor used is electrolytic which will normally only work properly when connected the right way round. On this basis, if you have a capacitor designed for a -ve earth system, it might not work with a  BSA +ve earth system.

ANDY HIGHAM

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Re: Condenser Missing?
« Reply #18 on: 30 June, 2018, 17:46:29 »
Hi, - interesting. As you know I'm having misfiring problems. My condenser is fitted remotely near the coil. Please explain why it needs to be near the points - I haven't heard this before.

Many thanks,
Phil

The condensor does not not need to be near the points, it needs to be electrically connected to the points-coil connection. Fitting the condensor near the coil is better because it is not getting cooked by engine heat

AWJDThumper

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Re: Condenser Missing?
« Reply #19 on: 01 July, 2018, 13:23:44 »
In a brand new bike it doesn't matter where the capacitor is. The potential problem is with older bikes and corroded earth contacts and degraded earth return paths. The points serve two purposes in a coil ignition system. When they open, they interrupt the current though the primary coil which then generates the HT voltage across the spark plug gap. However, when the points close they also perform the important task of shorting out the capacitor and reducing its stored charge to zero. With the capacitor close to the points, this will always happen. However, if the capacitor is mounted near the coil, there is a risk of a corroded earth connection between the capacitor and the points housing and this may result in the capacitor not being properly shorted out and discharged when the points close. If this happens, the quality of the HT spark may degrade and more arcing across the points may occur. It would be more of a problem with a 6V system rather than a 12V system.

Hancock

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Re: Condenser Missing?
« Reply #20 on: 04 July, 2018, 14:14:19 »
Tested coil got readings of primary 3.9 ohms secondary 4400 . Also measured ht lead and got 12000 ?

JulianS

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Re: Condenser Missing?
« Reply #21 on: 04 July, 2018, 14:22:28 »
With a copper cored HT lead you should be getting a zero reading - that is just the cable not including plug cap.

If your HT is a carbon cored resistive type then replace with copper cored.