1970 a65 capacitor

[Rory57]

I have recently stripped some of my Thunderbolt down during the lock down , I assembled it connected the battery up and it immediately blew the inline fuse. There appears to be a dead short somewhere, If I disconnect the capacitor it seems to cure it. Could this be a faulty capacitor. 

Any advice/ suggestions are more than welcome.

[Mark N]

Has the capacitor been fitted the correct way around?
I don't know much about "modern" bike electrics but if it's got an electrolytic capacitor it must be fitted correctly. And certain capacitors can explode if fitted incorrectly.

[Rory57]

Thanks for the suggestion. Yes it has it has a small and large spade connector. I also photographed everything before dismantling.

[idie]

They can short to earth. It seems you have proved that by removing it. Any car type capacitor will do the job, they all have the same value.

[Rory57]

Thanks for your replies.

[Bess]

Hi,
    Worth checking if the capacitor cable is down to earth first. Then disconnect the battery neg terminal, start the engine, turn on lights with main beam. It will be difficult to start with a faulty capacitor.

If it is suspect here are the capacitor testing instructions:

Best wishes...

[Allan G]

Who fitted the capacitor? They were normally only fitted to batteryless models. Or do you mean the points "condensers"?

[Bess]

Hi,
     In later models they were also fitted for use in emergency , when the battery was flat.

Best wishes...

[AdrianS]

Standard capacitors are around 220 micro farads.
You can buy small solid state ones which aren't polarity sensitive and are very cheap to buy.
A lot of nos or pattern ones are shite.
They can also be mounted remotely.

[Allan G]

Bess, it would never have been standard equipment on a road model, optional extra yes but never As standard from the factory.

[Bess]

Hi,
    Yep, capacitor kit part number 00-4402.

To be used with or without battery, useful in a road bike for emergency operation.

Best wishes...

[Rory57]

This is a photo of it , looks like it has always been fitted, certainly been there for the 3 years I've owned it and also for the previous owner of 2 years.
It has electronic ignition fitted also.

[Rory57]

Standard capacitors are around 220 micro farads.
You can buy small solid state ones which aren't polarity sensitive and are very cheap to buy.
A lot of nos or pattern ones are shite.
They can also be mounted remotely.

Thanks, where would the best place be to get an electronic replacement?

[Rory57]

Hi,
    Worth checking if the capacitor cable is down to earth first. Then disconnect the battery neg terminal, start the engine, turn on lights with main beam. It will be difficult to start with a faulty capacitor.

If it is suspect here are the capacitor testing instructions:

Best wishes...

Thank you.

[Rory57]

Hi,
    Worth checking if the capacitor cable is down to earth first. Then disconnect the battery neg terminal, start the engine, turn on lights with main beam. It will be difficult to start with a faulty capacitor.

If it is suspect here are the capacitor testing instructions:

Best wishes...

Very useful thank you.