Sun May 23, 2021 6:39 am

bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6010
Location: So Cal
 
bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6010
Location: So Cal
Sun May 23, 2021 6:39 am linkquote
Got a head scratcher for the collective.

Helping a friend with some upgrades to a late-70's US Super w/battery and points (new top end, brakes, suspension bits, etc...)

Bike's in very nice original condition, wiring and electrics are in good shape. It's been starting and running on the bench reliably, until yesterday.

Started it, it was idling for a minute, then shut down, like the key was turned off. Spark has now suddenly disappeared.

Replaced plug... no spark
Replaced plug wire ... no spark
Replaced HT coil ... no spark
Key switch working.
Kill switch is disconnected.
Points are new and gapped.

Multimeter and test bulb shows current coming from red ignition wire off stator when the flywheel spins.

What's going on? Bad condenser?
Sun May 23, 2021 7:01 am

Addicted
Vespa lxv 125 vie dell moda Chianti
Joined: 28 Aug 2012
Posts: 845
Location: Cheshire
 
Addicted
Vespa lxv 125 vie dell moda Chianti
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Sun May 23, 2021 7:01 am linkquote
years ago when I had lambretta I had a problem that bike started fine went wherever stopped but bike wouldn't restart, no spark left it 10 15 minutes and it was ok turned out to be condenser.
Sun May 23, 2021 8:01 am

Hooked
61 VBB and 79 P200
Joined: 01 Jan 2018
Posts: 208
Location: Folsom CA
 
Hooked
61 VBB and 79 P200
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Location: Folsom CA
Sun May 23, 2021 8:01 am linkquote
Sun May 23, 2021 1:52 pm

Hooked
Rat 2003 Stella 2T; 1979 P125x (in pieces, out for paint)
Joined: 12 Sep 2015
Posts: 313
Location: Madtown
 
Hooked
Rat 2003 Stella 2T; 1979 P125x (in pieces, out for paint)
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Posts: 313
Location: Madtown
Sun May 23, 2021 1:52 pm linkquote
Condensers are so cheap. I used to run points on my Moto Guzzi, and the standard advice was that if you thought the condenser was the problem, just buy a new one.
Sun May 23, 2021 2:17 pm

bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6010
Location: So Cal
 
bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
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Location: So Cal
Sun May 23, 2021 2:17 pm linkquote
Yeah I get that. I can replace it easily enough. That's not the point. I'm trying to understand what the failure is. How many volts needs to flow from the red wire to the HT coil before the HT coil produces a spark?
Sun May 23, 2021 2:24 pm

Style Maven
'74 50s x3 '78 P200 E '84 Cosa '91 PK50XL2 '58 AllState '68 Sprint '80 50special and a '66(?) Super125
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Sun May 23, 2021 2:24 pm linkquote
I don't know, but could you measure and compare to one of your bikes?
Sun May 23, 2021 2:27 pm

Addicted
Old douglas ..smallie with polini 115..super with nasco 177
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Location: New Zealand
 
Addicted
Old douglas ..smallie with polini 115..super with nasco 177
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Sun May 23, 2021 2:27 pm linkquote
condensor hack
Some where on you tube is a clip where a dude manually connects a new condensor EXTERNALLY to the engine with the old condensor still in place.

I did i it years ago on the side of the road and twisted the wires of a condensor in line to the old at the junction and duct taped it to the pod to get me going

If its on the bench just fit a new one..or do the hack as a test
good luck
Sun May 23, 2021 3:37 pm

bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6010
Location: So Cal
 
bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6010
Location: So Cal
Sun May 23, 2021 3:37 pm linkquote
LOL. I love everybody saying to put a new condenser on. No kidding. Gee why didn't I think of that? If I had a new condenser I would have put it on the bike yesterday.

We'll get one and put it on. What I'm trying to find out in the meantime is if anybody knows if a bad condenser will allow "some" current to pass through to the HT coil, but not enough to create a spark.

Voodoo: Good suggestion. I just did that. On my other points scoots the red wire produces around 3-4V per kick. This one seems to only produce around 1.8V.

So if it's the condenser, what exactly is failing?
Sun May 23, 2021 4:14 pm

Ossessionato
VSX, Stella 177, Stella 150, VNX1T, V9B1T
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Posts: 3276
Location: Staten Island, NY
 
Ossessionato
VSX, Stella 177, Stella 150, VNX1T, V9B1T
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Sun May 23, 2021 4:14 pm linkquote
You sure it's not the ignition coil failing, working poorly enough to generate a voltage, but not enough to spark and ignite?
Sun May 23, 2021 5:24 pm

Ossessionato
1963 VBB2T
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Ossessionato
1963 VBB2T
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Sun May 23, 2021 5:24 pm linkquote
SoCalGuy I can't help with what's going on but I can certainly understand why you would rather follow through to figure out what exactly is the problem rather than throw a part at it. Following to get edumacated.
Sun May 23, 2021 5:34 pm

bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6010
Location: So Cal
 
bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6010
Location: So Cal
Sun May 23, 2021 5:34 pm linkquote
swiss: No, not sure. Trying to rule things out. That and the flywheel are the only things left in the equation. Do ignition coils normally just lose voltage while a scoot is running? Never happened to me before. It was literally like the key turned off, and now no spark.

Lynn: Yep. Replacing parts without knowing if they're bad or not - just because they're cheap - strikes me as pretty low level mechanical problem solving.
Sun May 23, 2021 8:53 pm

Ossessionato
VSX, Stella 177, Stella 150, VNX1T, V9B1T
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Location: Staten Island, NY
 
Ossessionato
VSX, Stella 177, Stella 150, VNX1T, V9B1T
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Sun May 23, 2021 8:53 pm linkquote
SoCalGuy wrote:
swiss: No, not sure. Trying to rule things out. That and the flywheel are the only things left in the equation. Do ignition coils normally just lose voltage while a scoot is running? Never happened to me before. It was literally like the key turned off, and now no spark.

Lynn: Yep. Replacing parts without knowing if they're bad or not - just because they're cheap - strikes me as pretty low level mechanical problem solving.
Not sure, but possibly the ignition coil circuit has a short that happened while it was running?

Now no spark cause the short? Or a connection broke on the coil and its an open circuit now?

I'm just taking guesses here.

Take some readings directly off the ignition coil to see if anything suspect sticks out as different than through the condenser.

I'm only suggesting it cause my smallframe had no spark at all similarly even though the coils had continuity and I could see some voltage changes on kick when testing directly at the coil. Still don't know what the exact problem was, but when I got it back from Mercato, they had replaced the ignition coil along with the points and it was working fine after that.
Mon May 24, 2021 7:41 am

Style Maven
'74 50s x3 '78 P200 E '84 Cosa '91 PK50XL2 '58 AllState '68 Sprint '80 50special and a '66(?) Super125
Joined: 22 Nov 2010
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Location: seattle/athens
 
Style Maven
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Mon May 24, 2021 7:41 am linkquote
SoCalGuy wrote:
LOL. I love everybody saying to put a new condenser on. .....

Voodoo: Good suggestion. I just did that. On my other points scoots the red wire produces around 3-4V per kick. This one seems to only produce around 1.8V.

So if it's the condenser, what exactly is failing?
The condenser is like a shock absorber for your points, stores energy most of the time and gives it back when you need spark. Sounds like yours is leaky and just stealing energy, not giving any back .

Why don't you try putting on a new condenser?

Mon May 24, 2021 8:09 am

bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6010
Location: So Cal
 
bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6010
Location: So Cal
Mon May 24, 2021 8:09 am linkquote
Got one coming with along with a pile of other stuff, so we'll soon see.

I always understood the condenser to be basically a filter or capacitor. It momentarily absorbs the current when the points open to keep them from arcing, then passes it along to the HT coil.

Here's a question: If the condenser isn't letting enough current through, would a spark occur if the condenser were taken out of the circuit?
Mon May 24, 2021 8:14 am

Ossessionato
1963 VBB2T
Joined: 07 Nov 2012
Posts: 2511

 
Ossessionato
1963 VBB2T
Joined: 07 Nov 2012
Posts: 2511

Mon May 24, 2021 8:14 am linkquote
We all know how parts are sometimes similar in specifications on other vehicles , does anyone know if these condensers can be cross referenced , aren't they just a 12 volt?
Mon May 24, 2021 8:31 am

Style Maven
'74 50s x3 '78 P200 E '84 Cosa '91 PK50XL2 '58 AllState '68 Sprint '80 50special and a '66(?) Super125
Joined: 22 Nov 2010
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Style Maven
'74 50s x3 '78 P200 E '84 Cosa '91 PK50XL2 '58 AllState '68 Sprint '80 50special and a '66(?) Super125
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Location: seattle/athens
Mon May 24, 2021 8:31 am linkquote
They are rated in microfarads for their storage capacity and also for maximum voltage they can handle. A working old auto condenser would probably work on a Vespa.
Quote:
Here's a question: If the condenser isn't letting enough current through, would a spark occur if the condenser were taken out of the circuit?
I think so depending on how much juice your stator is kicking out, but you'll burn your point contacts up a whole lot sooner. And a condenser IS a capacitor, same thing.

Last edited by V oodoo on Mon May 24, 2021 8:40 am; edited 1 time in total
Mon May 24, 2021 8:39 am

Ossessionato
1963 VBB2T
Joined: 07 Nov 2012
Posts: 2511

 
Ossessionato
1963 VBB2T
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Mon May 24, 2021 8:39 am linkquote
V oodoo wrote:
They are rated in microfarads for their storage capacity and also for maximum voltage they can handle. A working old auto condenser would probably work on a Vespa.
You just shook my memory , microfarads , I recall now having to find one for my old British bike 30 years back. I bet I still have one or two in my stash. Voodoo any idea on what I would be looking for in microfarads?
Mon May 24, 2021 8:40 am

Ossessionato
Joined: 22 Oct 2011
Posts: 4455
Location: Tega Cay, SC
 
Ossessionato
Joined: 22 Oct 2011
Posts: 4455
Location: Tega Cay, SC
Mon May 24, 2021 8:40 am linkquote
SoCalGuy wrote:
Do ignition coils normally just lose voltage while a scoot is running?
They can and do as they age out and get hot enough. Or especially if the are make by Lucas - the prince of darkness.
Mon May 24, 2021 8:42 am

Ossessionato
VSX, Stella 177, Stella 150, VNX1T, V9B1T
Joined: 20 Jul 2018
Posts: 3276
Location: Staten Island, NY
 
Ossessionato
VSX, Stella 177, Stella 150, VNX1T, V9B1T
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Mon May 24, 2021 8:42 am linkquote
Tierney wrote:
Or especially if the are make by Lucas - the prince of darkness.




Mon May 24, 2021 8:45 am

Style Maven
'74 50s x3 '78 P200 E '84 Cosa '91 PK50XL2 '58 AllState '68 Sprint '80 50special and a '66(?) Super125
Joined: 22 Nov 2010
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Style Maven
'74 50s x3 '78 P200 E '84 Cosa '91 PK50XL2 '58 AllState '68 Sprint '80 50special and a '66(?) Super125
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Location: seattle/athens
Mon May 24, 2021 8:45 am linkquote
Sorry, I'm clueless, but I bet Google knows.

Yep, led me to a Studebaker forum of all places
Quote:
IIRC, 0.2 uF, +/- % is the typical value for an ignition condenser. So both of those are "close". Probably close enough to work OK. Old-time mechanic's manuals used to have a section illustrating how the build-up/pitting of the ignition points varied if the ignition condenser was under/over capacity for the coil being used.
Mon May 24, 2021 8:56 am

Ossessionato
1963 VBB2T
Joined: 07 Nov 2012
Posts: 2511

 
Ossessionato
1963 VBB2T
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Mon May 24, 2021 8:56 am linkquote
Tierney wrote:
They can and do as they age out and get hot enough. Or especially if the are make by Lucas - the prince of darkness.
I went through years of abuse with Lucas prince of darkness Positive ground poor sense of humour.
Mon May 24, 2021 9:03 am

bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6010
Location: So Cal
 
bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6010
Location: So Cal
Mon May 24, 2021 9:03 am linkquote
swiss & Tierney: If the ignition coil on the stator shorted or developed an open circuit while running the red wire would no longer produce current, correct? It still does, so doubt it's the coil.
Mon May 24, 2021 9:08 am

Ossessionato
1963 VBB2T
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Ossessionato
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Mon May 24, 2021 9:08 am linkquote
I found 3 in my stash but none have numbers on them, I bet they go bad after 30 yrs?



Tue May 25, 2021 3:47 pm

bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6010
Location: So Cal
 
bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6010
Location: So Cal
Tue May 25, 2021 3:47 pm linkquote
Think I found the problem. Took stator off... the black ground wire inside the plastic sheath was in, um, less than perfect condition.



Tue May 25, 2021 4:10 pm

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1963 VBB2T
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Tue May 25, 2021 4:10 pm linkquote
SoCal that wiring is in horrible condition.
Tue May 25, 2021 4:37 pm

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Joined: 22 Oct 2011
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Tue May 25, 2021 4:37 pm linkquote
Good man, SoCal
Tue May 25, 2021 4:44 pm

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Tue May 25, 2021 4:44 pm linkquote
Ok so if the ground is rough why would it matter if it was shorting out to metal ?
Tue May 25, 2021 5:02 pm

bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
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Location: So Cal
 
bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
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Tue May 25, 2021 5:02 pm linkquote
Lynnb wrote:
Ok so if the ground is rough why would it matter if it was shorting out to metal ?
Don't think it was shorting out to metal. I don't think it was providing a reliable ground.
Tue May 25, 2021 5:42 pm

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1963 VBB2T
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Tue May 25, 2021 5:42 pm linkquote
SoCalGuy wrote:
Don't think it was shorting out to metal. I don't think it was providing a reliable ground.
Ahh ok now that makes perfect sense, nice find.
Tue May 25, 2021 6:58 pm

Banned
2:6
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Location: San Francisco
 
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Tue May 25, 2021 6:58 pm linkquote
for future reference, points should "work" without a condenser and on a magneto it's almost impossible to have too large a condenser.

So from a trouble shooting perspective you can add a condenser at the coil between the lead from the points and ground, this will double the capacitance. if this solves it the existing one is likely failed in an open state.

If the exiting condenser is shorted, then only disconnecting it will solve anything.
Wed May 26, 2021 12:28 am

Ossessionato
1963 VBB2T
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Wed May 26, 2021 12:28 am linkquote
oopsclunkthud wrote:
for future reference, points should "work" without a condenser and on a magneto it's almost impossible to have too large a condenser.

So from a trouble shooting perspective you can add a condenser at the coil between the lead from the points and ground, this will double the capacitance. if this solves it the existing one is likely failed in an open state.

If the exiting condenser is shorted, then only disconnecting it will solve anything.
Good tidbit of info , thanks.
Wed May 26, 2021 6:51 am

Hooked
1958 Allstate 177VMC, 2005 70cc Yamaha Vino
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Posts: 410
Location: Philadelphia
 
Hooked
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Location: Philadelphia
Wed May 26, 2021 6:51 am linkquote
Have you thought about getting a new condenser?



Wed May 26, 2021 8:24 am

Addicted
'64 Motovespa 150S (177) , '66 Allstate SF, '65 VBB, '66 180SS
Joined: 27 Mar 2013
Posts: 927
Location: S.Salem, NY
 
Addicted
'64 Motovespa 150S (177) , '66 Allstate SF, '65 VBB, '66 180SS
Joined: 27 Mar 2013
Posts: 927
Location: S.Salem, NY
Wed May 26, 2021 8:24 am linkquote
FWIW... I think the guy in that video has it wrong. The condenser ( capacitor) absorbs the energy that would cause the points to arc and burn when they separate until the circuit closes again and it is released into the circuit. We all know the plug fires when the points open and not when they close. YouTube...

Yes, a motor will run without the condenser.

The red and yellow wires are connected at the condenser, which is basically piggy-backed onto the circuit and can be attached at any point between the points arm and the HT coil.
Wed May 26, 2021 11:07 am

bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6010
Location: So Cal
 
bodgemaster
63 GL, 76 Super (x2), 74 Primavera (x2), 79 P200, 06 Fly 150
Joined: 26 Sep 2013
Posts: 6010
Location: So Cal
Wed May 26, 2021 11:07 am linkquote
New ignition ground wire and it's sparking like Fourth of July.

Thanks all.
Wed May 26, 2021 11:25 am

Addicted
'64 Motovespa 150S (177) , '66 Allstate SF, '65 VBB, '66 180SS
Joined: 27 Mar 2013
Posts: 927
Location: S.Salem, NY
 
Addicted
'64 Motovespa 150S (177) , '66 Allstate SF, '65 VBB, '66 180SS
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Location: S.Salem, NY
Wed May 26, 2021 11:25 am linkquote
Good one.
Wed May 26, 2021 1:15 pm

Ossessionato
1963 VBB2T
Joined: 07 Nov 2012
Posts: 2511

 
Ossessionato
1963 VBB2T
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Posts: 2511

Wed May 26, 2021 1:15 pm linkquote
SoCalGuy wrote:
New ignition ground wire and it's sparking like Fourth of July.

Thanks all.
Awesome well done.
Wed May 26, 2021 3:14 pm

Ossessionato
VSX, Stella 177, Stella 150, VNX1T, V9B1T
Joined: 20 Jul 2018
Posts: 3276
Location: Staten Island, NY
 
Ossessionato
VSX, Stella 177, Stella 150, VNX1T, V9B1T
Joined: 20 Jul 2018
Posts: 3276
Location: Staten Island, NY
Wed May 26, 2021 3:14 pm linkquote
Congrats! And of course it had to be some random unexpected thing making you work for it!
Thu May 27, 2021 2:49 am

Style Maven
'74 50s x3 '78 P200 E '84 Cosa '91 PK50XL2 '58 AllState '68 Sprint '80 50special and a '66(?) Super125
Joined: 22 Nov 2010
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Location: seattle/athens
 
Style Maven
'74 50s x3 '78 P200 E '84 Cosa '91 PK50XL2 '58 AllState '68 Sprint '80 50special and a '66(?) Super125
Joined: 22 Nov 2010
Posts: 8250
Location: seattle/athens
Thu May 27, 2021 2:49 am linkquote
Nice one Mike!
Another innocent old condenser w/ lots of life still to give saved from the dust bin by your determination to really know stuff, dig up the facts and not just accept conventional wisdom.



This is as close to your place that I could find, wear it proudly regardless!
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