starter switch fried

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Hullsfire

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Jun 10, 2012
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I'll preface this with - not strong electrically.
My 1971 Commando has been running beautifully since last fall after a tear down and some nice new parts.

Yesterday she started and died after a couple minutes at idle.
Same after a couple more attempts. A couple times it died after I toggled the lamp over to on.

All connections look good (everything was cleaned and many upgraded connections made - not all though)
New trispark and single coil from CNW
New three phase alternator and reg/rectifier (eliminated zener diode and 2MC capacitor)

Battery voltage is good but when the ignition switch is turned on the voltage sinks quickly.
Bike won't start, obviously, in that condition.
It was a new Japanese cheapo ignition switch

Am I looking at just a new switch or something more sinister?

Thank you for any help.
 
Hullsfire said:
Battery voltage is good but when the ignition switch is turned on the voltage sinks quickly.
Click to expand...

How old is the battery?

If you suspect it could be an ignition switch problem, try temporarily bypassing the switch (connect the white to brown/blue).
 
Battery voltage is good but when the ignition switch is turned on the voltage sinks quickly.
Click to expand...

and that should not happen

your battery may even charge up fully just fine, but that is not an indication of a good battery

I would buy a new battery and you can confirm this by turning on the headlight high beams without the motor running, wait about 3 minutes and then put your volt meter on the battery, fully charge battery first of course

voltage should be in the range of 12.3-12.5
 
Battery is new as of last year.
And as soon as the switch is off the voltage jumps right back up to where it should be.
 
then the voltage bleed is likely in your ignition switch

I would take the rubber boot off and then unscrew the unit from the frame tube

so that you can pull off the leads and take a good look at the male ignition prongs

they and even the female leads may be badly corroded and thus discharging voltage?

also possible that the insides of the ignition switch could be corroded and gummed up

if your switch is original it is some 40 years old, could be time to replace it?

is it possible you have a weak ground going from the positive terminal to frame?

I would do my above fast and easy battery headlight with high beam load test first and go from there
 
It was a new (last year) ign. switch though a cheaper Japanese one.

So I ran a jumper from the battery to the kill switch.

Warning light immediately is on - that should be normal given the circuitry.
Then in order to get the lights on I had to turn the switch to the on position (ie. The brown/blues)

Battery voltage stayed true holding 12 + volts.

This jumper provides power through R hand cluster to the white wires hub under tank and onto L hand cluster, lamp housing (warning light and front brake switch), with the last white wire from hub travelling to the ign. switch.

I'm not understanding why, if the switch is gone, I would need to turn the key to the position where I originally thought the problem originated from.
 
Any chance of the new reg./rectifier being bunk and sucking juice before power gets to the switch?
 
Hullsfire said:
Any chance of the new reg./rectifier being bunk and sucking juice before power gets to the switch?
Click to expand...

Try disconnecting it (as it isn't doing anything while the engine isn't running)?
 
Hello folks. I've been contemplating this issue and it's taken a turn for the worse.
I have no spark now.

One change I made - I had a suspect grounding connection (last year I had rewired all grounds to a single connecting point and I didn't like my soldering job), and so I tied in all ground wires to a new connector, then from it a short pony length of a single ground wire to the grounding point.

Turned the key (power on) and blew the fuse.
New fuse but now no spark from plugs when grounded on engine.

I'm lost.
Damaged coil?
 
Electronic ignitions strongly dislike a poor corroded ground to the point where the electronics give up. This is a worst case scenario.
 
Hullsfire said:
No corrosion. I am wondering if all grounds into one could cause resistance?
Thanks.
Click to expand...

I read somewhere years ago that if you grounded to many things to a single point it can cause radio interference (was car related) but just as with power side of wiring then all ground wires must be large enough to carry the load an if multiple items are on same ground wire it must be large enough to carry all loads at once.

Do you have the capacitor (big blue 2 ohm type) fitted as they can give trouble.
 
I removed the capacitor when I put in a new three phase stator and reg/rect. kit.

I will undo my step and ground each wire individually. This makes sense to me too.

Tomorrow I will run a jumper again to the kill switch and do a load test with the lights on. Also jumper directly to the tri spark blk/yellow and check for spark.
 
Hullsfire said:
I removed the capacitor when I put in a new three phase stator and reg/rect. kit.

I will undo my step and ground each wire individually. This makes sense to me too.

Tomorrow I will run a jumper again to the kill switch and do a load test with the lights on. Also jumper directly to the tri spark blk/yellow and check for spark.
Click to expand...

Individual grounding is not the answer.
First, verify the battery.. http://www.amazon.com/BA5-100-1200-Cran ... ery+tester
most auto parts stores have them.

The age of the battery is no guarantee it's still viable.

If the battery proves good, use jumpers to bypass the key switch, and kill switch.
 
If you list your location then maybe someone here could make a house call and straighten this out because it seems like you are digging yourself into a deeper hole. Or take it a reputable shop that has actually worked on Nortons, possibly the guys who did your engine and trans work.

With a multimeter and some logic it should be fairly quick to find. Don't assume anything is good just because it has been replaced. Could be something really simple like a cracked bullet connector. These are notorious -- check all of the double (accept up to 4 wires) and triple (up to 6 wires) ones in the HL shell and under the tank. Also, there have been a few Tri-Spark deaths but very unlikely to be the cause of your voltage going away.
 
How old is the Tri-Spark?
Mine did the same thing last month. Voltage drop, blown fuse and then no spark. Replaced the Tri-Spark with the new version and no more problems.
I tried everything like bypassing the switch, putting power to the TS unit with no joy until I replaced the TS.
 
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