# Points Ignition short?



## InvalidID (Feb 18, 2011)

Being a relatively young fella I haven't had the good fortune to mess with points ignition systems yet. While I have a basic (VERY BASIC) grasp of how these things work, I'm not sure how to troubleshoot the bigger stuff.

So here's my issue. Older motorcycle (1979 GS850) with points ignition. Not getting spark of course. The multimeter shows continuity to both sides of the contacts at all times, even when the points are open. This is wrong yes? If so, why is this happening and how do I fix it?

Also, I show a weak spark on the points when turning it over but only every so often, not on every rotation. Coils bad? That was my first thought as I tested the end of the plug wires and showed very little power (the needle on the meter moved when the plug should have been firing, but barely). But with continuity on both sides of the contacts I'm not sure if it's the coil or a short somewhere in the points now...


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## Evons hubby (Oct 3, 2005)

How are you testing this with your multimeter? I always used a regular test light when working with points. Attach the clip on test lite lead to the wire leading from the coil to the points (usually at the coil but if the terminal at the distributer is handy thats ok too) and ground the light anywhere you have a solid ground. When the ignition is turned on and the points are open the light comes on. (or should if things are right) If the points are closed it grounds out the circuit and your light will go out. Turn the engine over until they open, and the light comes on. If your light stays off regardless of the opening of the points, you have a short somewhere in the circuit. This is most likely caused by a shorted condenser. It can also be the points themselves, highly unlikely, or it could be the wire itself grounding against something in the distributor. If your light stays on regardless of the position of the points then you have an "open" somewhere in the circuit, thats usually caused by dirty/burned points, not allowing them to ground out the circuit when closed. I am guessing by your description that your condenser has failed or your points are fouled. The obvious fix is to simply replace them. In the dark ages we called this procedure a "tune up", which included replacing the spark plugs and making adjustments to the carb. Best done every 10 thousand miles or so. Another thing to check for is points not opening due to improper gap setting. This is normally caused by the fiber or nylon block that runs against the cam wearing down and not opening the points.


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## InvalidID (Feb 18, 2011)

Yvonne's hubby said:


> How are you testing this with your multimeter? I always used a regular test light when working with points. Attach the clip on test lite lead to the wire leading from the coil to the points (usually at the coil but if the terminal at the distributer is handy thats ok too) and ground the light anywhere you have a solid ground. When the ignition is turned on and the points are open the light comes on. (or should if things are right) If the points are closed it grounds out the circuit and your light will go out. Turn the engine over until they open, and the light comes on. If your light stays off regardless of the opening of the points, you have a short somewhere in the circuit. This is most likely caused by a shorted condenser. It can also be the points themselves, highly unlikely, or it could be the wire itself grounding against something in the distributor. If your light stays on regardless of the position of the points then you have an "open" somewhere in the circuit, thats usually caused by dirty/burned points, not allowing them to ground out the circuit when closed. I am guessing by your description that your condenser has failed or your points are fouled. The obvious fix is to simply replace them. In the dark ages we called this procedure a "tune up", which included replacing the spark plugs and making adjustments to the carb. Best done every 10 thousand miles or so. Another thing to check for is points not opening due to improper gap setting. This is normally caused by the fiber or nylon block that runs against the cam wearing down and not opening the points.


 So ordering new points and condenser WAS the right idea. I wasn't sure WHY exactly, but I was sure something in there was in need of replacement. I was hoping it wasn't a bad coil which is a bit spendy.

Thanks a ton YH.


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## OkieDavid (Jan 15, 2007)

I agree with YH. Continuity through open points almost has to be a bad condensor. Change out the points/condensor and I bet you are good to go. I'm not sure what the suggested gap is supposed to be but back in the day, I always used a matchbook cover to set them. Do they even still sell/give away matchbooks? Man, I'm too old.


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## Evons hubby (Oct 3, 2005)

OkieDavid said:


> I agree with YH. Continuity through open points almost has to be a bad condensor. Change out the points/condensor and I bet you are good to go. I'm not sure what the suggested gap is supposed to be but back in the day, I always used a matchbook cover to set them. Do they even still sell/give away matchbooks? Man, I'm too old.


16 thousands will work on most points. Its best to check the manufactures specs though. My ferguson tractors... (fifties vintage) call for 20 thousandths and I have found it makes quite a difference in the power curve.  matchbooks are getting harder to find all the time.


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## Evons hubby (Oct 3, 2005)

InvalidID said:


> So ordering new points and condenser WAS the right idea. I wasn't sure WHY exactly, but I was sure something in there was in need of replacement. I was hoping it wasn't a bad coil which is a bit spendy.
> 
> Thanks a ton YH.


Yer welcome! If your motorcycle is like mine and sits for extended periods, I recommend cleaning the points every riding season.


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## InvalidID (Feb 18, 2011)

Matchbooks I got in spades over here. I think the gap was something like .88mm or something. I have the manual around here somewhere. I was thinking matchbook too though. That's the gap you set when open or closed BTW?

Is it worth spending the $300 bucks to switch to electronic ignition do ya think?


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## Evons hubby (Oct 3, 2005)

InvalidID said:


> Matchbooks I got in spades over here. I think the gap was something like .88mm or something. I have the manual around here somewhere. I was thinking matchbook too though. That's the gap you set when open or closed BTW?
> 
> Is it worth spending the $300 bucks to switch to electronic ignition do ya think?


There is no gap when the points are closed.  To set the gap turn the engine slowly until the points are at their widest gap, (the rubbing block will be in contact with the highest point of the cam) then adjust to 16 thousandths. Is it worth 300 bucks to set your points once a year? I dunno, my time isnt worth a whole lot these days. Yours could be worth far more than mine.


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## Evons hubby (Oct 3, 2005)

I recently went through a 1971 Norton for a buddy of mine.... all new seals, gaskets, anything that time had taken a toll on. It had been sitting since 1971... had 64 miles on it! He is not too mechanically inclined so had me put in the point/electronic conversion kit while we had it all apart. It was something like 150 bucks I think. In his case he felt it was worth it, due to the history of that particular model. They were notorious for point problems. After looking through the original mechanism I understood why.... very poor design from the factory. Hopefully the kit will be trouble free.


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## bikehealer1 (Oct 8, 2009)

Start with a point gap of .014 (fourteen thousandths) 

Remember, one set controls 1 and 4 cylinders, while the other controls 2 and 3. 

Weak or loss of spark on a points type bike can be caused by many things...
1.- dirty or improperly gaped points
2.- shorted condenser
3.- loss of backing plate ground ( due to oil/grease buildup, corrosion etc...)
4.- grounded spade connector at points
5.- failing coils
6.- failing plug caps ( ohm test with a GOOD ohm meter.. should be 5kohm's or less...anything more is a bad plug cap.)
7.- bad battery connections- lack of proper voltage to coils results in weak spark conditions. check all your connections, including ground to engine. A bad starter will cause such a voltage drop that the ignition will fail to spark.
8.- ohm test the harness to the points plate ( with the points disconnected and harness disconnect from coils and or main harness, ohm test each lead for broken wires.) had a CB550 with spark on 2 and 3 only one time with a bad wire in the points harness.


If it were me, I'd go with the Dyna Ignition system using the matching Dyna coils. Once you set it, it's good.


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## InvalidID (Feb 18, 2011)

The wires that connect to the armature need to make contact with the spring but not the screw that holds them in yes? How is this accomplished? Seems like it would be nearly impossible to set up. I'm guessing this is what you mean by grounded spade connector?


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## k9 (Feb 6, 2008)

Yvonne's hubby said:


> I recently went through a 1971 Norton for a buddy of mine.... all new seals, gaskets, anything that time had taken a toll on. It had been sitting since 1971... had 64 miles on it! He is not too mechanically inclined so had me put in the point/electronic conversion kit while we had it all apart. It was something like 150 bucks I think. In his case he felt it was worth it, due to the history of that particular model. They were notorious for point problems. After looking through the original mechanism I understood why.... very poor design from the factory. Hopefully the kit will be trouble free.


A problem with Lucas Electrics points???? Say it isn't so!!!! Joseph Lucas the Prince of Darkness.


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## InvalidID (Feb 18, 2011)

Well, I got the points straightened out, the timing seems about right... time to move on to the carbs.... :smack:


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## foxtrapper (Dec 23, 2003)

InvalidID said:


> Is it worth spending the $300 bucks to switch to electronic ignition do ya think?


Points are simple and easily fixed. At the worse, you run your matchbook cover through them at the start of the riding season. On bikes, the points tend to last for many years. While I like electronic ignitions, I'd see no reason to spend the money to switch on this bike.


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## bikehealer1 (Oct 8, 2009)

Make sure none of your brass floats are sunk. Make sure the bowl vents are not clogged ( you have no idea how many carb flooding issues are from clogged bowl vents.) Check each passage with carb spray for positive flow twice.Check your pilot jets twice. ( pilot jets have a tendency to hold on to gunk in the passage, clogging back up after you check the first time.) Bench test before remounting ( put fuel to them to make sure you have no leaks).Each bowl should have between 1.5 to 1.75 ounce of fuel in them.(I have been doing carbs for 16 years, and can pretty much tell you what most carbs should have in the float bowl to run properly.) I drain mine into a shot measure that holds 2.25 ounces. Nothing like getting a set of carbs reinstalled only to discover one is flooding like a s.o.b. Make sure to replace the o-rings behind the intake pipes ( part no. 09280-32006). They are only $2 or $3 a piece and trying to use silicone to correct an air leak is a waste of time. Guarantee you they are flat. Synchronize after you reinstall and get it running. It may seem to be running right, but.... its always good to check. 



Just my 2Â¢. I do mail order rebuilds occasionally, and have a few local restorers who use me as well. Old carbs dont scare me. :grin:


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