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1972 Suzuki T500 Spark problem
Posted: Sat Jun 06, 2020 10:44 am
by Wernvilla
Hello,
I know this issue comes up a lot on the forum.
I have an issue.....
Got great spark on Right side
No spark on left
Been checking points multiple times and all is set good.
I checked the voltage with the points open
Right side - 12.4v
Left side - 23.2m v no spark - got little voltage not alot
Would this be down to Regulator fault?
Coils have been tested
Primary - 4.4k
Secondary - 12.5k
Re: 1972 Suzuki T500 Spark problem
Posted: Sat Jun 06, 2020 12:26 pm
by jabcb
Not sure what you have based on your explanation.
Looks for voltage drops that are not good:
With left point closed & right point open, check voltage at both primary sides of both coils.
With left point open & right point closed, check voltage at both primary sides of both coils.
Re: 1972 Suzuki T500 Spark problem
Posted: Sat Jun 06, 2020 12:37 pm
by Wernvilla
With left point closed & right point open, check voltage - 0.00v on both
With left point open & right point closed, check voltage - left - 0.00v right 11.3v
Re: 1972 Suzuki T500 Spark problem
Posted: Sat Jun 06, 2020 2:04 pm
by Wernvilla
For side with closed points:
coil voltage for orange wire should be close to 12.4v - I got 12.2v
coil voltage for other wire (White) should be close to 0v - I got 12.2v
voltage on coil side of points should be about 0v - I got 0v
Re: 1972 Suzuki T500 Spark problem
Posted: Sat Jun 06, 2020 4:51 pm
by jabcb
Did you replace the points? Or remove them for cleaning or inspection?
Did you disconnect & reconnect any the the ignition circuit wiring?
Re: 1972 Suzuki T500 Spark problem
Posted: Sat Jun 06, 2020 11:22 pm
by Wernvilla
Fitted new points and condensers
And yes i have had the loom apart
Re: 1972 Suzuki T500 Spark problem
Posted: Sun Jun 07, 2020 3:14 am
by jabcb
You probably incorrectly installed the left points. If the insulators & other parts are in the wrong order, you can end up with no current going through the coils, or current always going through the coils.
See:
PointDiagram1 by
jabcb, on Flickr
Re: 1972 Suzuki T500 Spark problem
Posted: Sun Jun 07, 2020 12:51 pm
by Wernvilla
I got spark at both sides on the points.
If i manual move points on left side i get a small spark from plug.
Right side is sparking great.
Thats for drawing, thats really helpful and very well drawn
Re: 1972 Suzuki T500 Spark problem
Posted: Sun Jun 07, 2020 1:20 pm
by jabcb
This kind of problem is not easy to diagnose via a forum.
You should not be getting much of a spark at the points. If the spark at the left points appears bigger, you might have a bad condenser.
You could try running a temporary wire from the coils to the right points. If you get a good spark when you test the right coil, and a bad spark when you test the left coil, then the coil is suspect.
You might have a bad plug cap. The resister in the cap can go bad.
Also check & clean the electrical connectors between the coils & points. Make sure they are properly seated.
Make sure to charge up the battery too. The electrical systems on these bikes are marginal. It might be fine with a good fully-charged battery. With a weak battery, these bikes tend to loose spark on one cylinder before the other one.
Re: 1972 Suzuki T500 Spark problem
Posted: Sun Jun 07, 2020 5:59 pm
by alanr
Was it running well before new points put in.
Re: 1972 Suzuki T500 Spark problem
Posted: Mon Jun 08, 2020 1:58 am
by Wernvilla
Bought bike as a non runner
I finally got spark on both sides
I refitted the original points and now got spark on both.