Condenser fail symptoms

[Kawksam]

Kawks been at garage for day and half and still quizzed what's wrong with it.

Top end off nothing wrong in there
Exhaust not coked up but missing baffle
Carb float height reset
Carb rejetted back and forth
Worked abit better with air filter off no change
Points resett back and forth

Only thing electrical has to be condenser that is failing what would symptoms be.

[The Shaggy D.A.]

If your condenser's failing you'll get rough running and pitted points - how do your points look? More likely to be a bad connection than the condenser actually failing though.

What bike is it, and what's it doing (or not doing)?
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Currently : Royal Enfield 350 Meteor
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[kingsmith]

Condenser

I've never had a condenser (an old-fashioned term for 'capacitor') fail in 40 years, but I've been carrying a spare in each of my MGBs for probably the whole time I have had them. Ignition Theory will explain the function of the condenser, which isn't just to prevent points burning but significantly boosts the energy in the HT and the spark at the plugs. The reduction in points burning is merely a side-effect of putting enery into the spark instead. A diode would be much more effective at quenching the spark at the points, but would do nothing to improve the spark at the plugs.
When the condenser isn't in circuit the plug spark energy is much reduced but will just about jump a plug gap, but that is 'on the bench' i.e. plug out looking at the gap. Under compression the spark finds it harder to jump the gap and fire the mixture. So it is possible that your engine will start and run, but misfire badly under acceleration. The tach will be relatively steady while this is happening, so you know it isn't anything else in the primary circuit like points, coil primary, ignition supply or connections. Note that this symptom is identical to when the HT circuit is breaking down somewhere, like at the rotor or distributor cap, because the HT voltage has to rise higher before the spark can jump the plug. But if you can reproduce the problem with a timing light connected to the coil lead and plug leads you can isolate it a bit more by watching the flashes as it happens. If the flashes start getting erratic or missing altogether on the plug leads but not the coil lead, then you know the problem is with the cap and/or rotor. If the erratic flashes are on the coil lead as well, then it will be coil or condenser. The condenser is much cheaper (and should be carried as a running spare anyway) than a coil, and you don't even have to disturb the distributor to test the theory. Simply croc-clip the condenser between the points terminal on the coil (white/black) and earth (case to earth although they are not polarity sensitive) and if that solves the problem you know it is the condenser. If not it must be the coil, although coil HT failures seem to be very rare.


quick google search
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[Kawksam]

[cb1rocket]

new points and condensor and go from there. there cheap bits so give em a go first.

One thing i found with my bike was that the HT lead to spark plug cap was breaking up. Replaced that and all was good.

Awkward to diagnose sometimes