what causes a white spark on points ignition?

[supersonictoys]

well I have an issue that has nothing to do with my GS but one of my other bikes has me confused. I have a 72 honda cb450 twin which has points ignition and for some reason the right hand plug keeps fouling out even though there is no smoke or oil consumption. I happened to be trying different things today and pulled the plug out of the cylinder that has been having issues and started the bike up with the plug laying on the head and the spark is SUPER BRIGHT and white , not blue at all! did the same with the good cylinder and it has a nice normal blue spark. what gives here?? any ideas? someone told me years ago what causes this but I need to hear it from someone who knows for sure. LOL thanks for any help!

 

[Big T]

White is better than blue

The 450 is a single coil bike, isn't it? Both plug leads come off the coil?

 

[supersonictoys]

2 coils ,2 sets of points. dont think you understand what I mean by white spark. looks like someone is welding. super BRIGHT. very weird

 

[Nessism]

When's the last time you replaced the condensers?

 

[supersonictoys]

Have never changed them and it's probably got the originals from 72 but the bike had only 6k and sat for 30 years. Will a condenser cause this and what is actually happening to make it spark so strangely?

 

[chuck hahn]

did you take a womens nail file and polish the points themselves?? That never hurts to ensure a good connection as the points work.

 

[rustybronco]

Is the set of points for the coil in question arcing? if so, replace the condenser(s).

 

[Nessism]

Have never changed them and it's probably got the originals from 72 but the bike had only 6k and sat for 30 years. Will a condenser cause this and what is actually happening to make it spark so strangely?

Yes, the condensers do effect the spark quality. Points and condensers are maintenance items and should be changed occasionally. You can file the points if necessary but I'd just replace the set and relax knowing you have good parts in there.

 

[supersonictoys]

havent looked at the points to see if they are sparking insanely bright yet like the plugs, will do that this morning. I did clean the points by removing them, disassembling them, wire wheeling the contacts then carefully filed down the rough spots, re lubricated them and reinstalled and gapped to factory specs. I was thinking maybe my rectifier was going out and I was getting some ac current into the system or something. guess you need to see this spark to understand. its impressive!

 

[rustybronco]

What is your charging system voltage?

 

[Nessism]

Yes, check the charging system but that has almost nothing to do with spark - unless the battery is flat.

 

[BIKERTUCKER]

I Have a 71 and 73 CB450. Have never heard of this problem, would guess it is not caused by the points,they would be on the primary side of the coil. Perhaps it's a problem as suggested with the condenser, also remember there is a resistor inside the spark plug boot that can be accessed by unscrewing the brass cap with a flat tip screwdriver. I think i would swop parts in the ignition
system from one side to the other till the problem switches sides.
Example Swop spark plugs from one side to the other, if the problem follows the spark plug, the problem is the spark plug.
You could also trade the leads from the condenser, if the problem follows the condenser lead, the problem is the condenser. Also remember even though the condenser is a single component it houses two condensers, one for each side, two wires leaving the unit. by swopping wires your swopping condensers. You get the idea.
Good luck, please post when you find the problem. Very strange.

Tim

 

[BIKERTUCKER]

Since a final post was never made I don't know if the problem was found as to what was causing a very bright white glare instead of a blue spark at spark plug gap. Put my 73 CB450 on the lift for some spring time maint. and to my suprise the left spark plug would produce a bright white light instead of an expected blue spark. Bike seemed to be running fine but what caused me to check plugs was the left spark plug was mostly black as if the left side was running too rich. Replaced left spark plug with a new one I had in stock and, nice blue spark returned at the plug gap. Went on a fourty mile ride, removed plug and color of plug was back to normal. In this case the bright white light at the plug gap was caused by a faulty plug. In the past I have found open plugs producing a weak spark
but have never seen a white light before. Thought I'd reply to post because this could apply to bikes in this forum also. If anyone has an idea as to how a spark plug could produce a super bright white light, instead of a blue spark I'm out of ideas.

Take Care

Tim