Author Topic: Non BSA spark issues.  (Read 115 times)

Offline A10 JWO

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Non BSA spark issues.
« on: 02.12. 2019 15:22 »
One of my trials bikes ( non battery ) generates the spark via the alternator via a 6 volt coil, points and condenser. The bike is not running but I have a bright blue spark. I suspect I have no spark when the plug is fitted and under compression. It has been suggested that a large blue spark is wrong and something may be breaking down. I have heard of plugs not sparking under compression in the past but cannot find any reference to this. All fuel aspects and compression are fine. I know there will be a few experts on here, thank you.

Online RDfella

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Re: Non BSA spark issues.
« Reply #1 on: 02.12. 2019 17:31 »
Blue spark is good. It's the anaemic reddish ones which fail under compression. Is it timed right?
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Offline A10 JWO

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Re: Non BSA spark issues.
« Reply #2 on: 02.12. 2019 17:51 »
Was running fine before being put away. Have ordered a new coil and condenser. will fit a new plug as well. I googled no spark under compression, loads of answers. Will see what the postman brings.

Offline Triton Thrasher

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Re: Non BSA spark issues.
« Reply #3 on: 02.12. 2019 18:24 »
Put some petrol in through the spark plug hole and see if it fires.


Offline A10 JWO

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Re: Non BSA spark issues.
« Reply #4 on: 06.12. 2019 17:26 »
Fitted a new coil and condenser, nice smaller spark and now starts first kick.