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Ignition Timing 1973 CB350

2K views 15 replies 5 participants last post by  Bill H 
#1 ·
Hello all! First post, so forgive me if I miss something. I’ve looked all over for this info and found some cases similar but couldn’t quite figure it out. Brand new to motorcycles (first bike) and I’m doing some engine tuning. I’m trying to set my points and time my ignition. I followed the Common Motor Collective how-to video and couldn’t get my test light to illuminate. I also used feeler gauges to set the left point and the gauges had a little bit of oil on them. Not sure if that’s an issue. I got the test light to illuminate two times by attaching it to different locations but couldn’t replicate it.

I’m stuck on this and want to get my timing set right. Are my coils not delivering power? Is the wiring bad? Are my points bad? Am I missing something simple? Please assuming I know NOTHING when explaining...I’m not even sure I know exactly where the coils are, I know nothing about electrical, etc.
Thank you in advance!
 
#2 ·
Use an OHM meter and put the + on the contact point where the wire mounts on the points. put the - on ground turn on the ing switch and see if you get a reading. Dont leave the switch on too long it will overheat the coils. If you get a reading chances are you have power to the points. I dont Know what kind of test lamp you have but run a wire from the + side of the battery thru the lamp to the coil side of the points and a ground wire from the points to ground. close the points and the light should be on. Take your finger and open the points and the light should go out. If that works then set your points after cleaning the oil off then turn the crank and see if the points open on the timing mark. The light should go out just as the marks match. If at any point something doesnt work you need to find the problem. If the light goes out on the mark just set the points as per the manual.

Bill
 
#4 ·
Does this bike have a battery? I was looking at the pictures on your introduction post and didn't see one. The static light will not luminate without one. Also, the bike will not run right without a battery. The ignition requires a steady supply of power. Some people who strip the wiring down take a little too much off. To make it run, you will need a 12v source. Apply +12v to the primary side of the coils and kick it over. it should fire. On the stock wiring, the wires that connect to the coils are black with a white stripe. Then on the other end of the primary side of the coil is either (depending on left or right) yellow or blue.
 
#5 ·
That light should be fine. With the power on, the light should come on when the points are open. You can use it to probe the primary side of coils for power.
 
#7 ·
Do both points have to be open? Or just the one I am touching with the test light?
Can I just poke the outside of any wire with the test light connected to ground to see if there's power running through that wire? Sorry, square one... haha
 
#8 · (Edited)
I'm not following how you're testing this. Basically here's what happens with ignition.

Points open and the spark happens.
When the F/LF mark on the flywheel meets the mark on the stator then the points should open.
The light is to help you see precisely when the points open.

So, if you have power at your points, then you need to ground your test light and your light will come on when the point open.

If you have the light hooked up to the + on the battery, then the light will turn on when the points close.

Edit: if you do the bottom one, unplug the points or your blow your test light
 
#10 ·
Yea, I think that all makes sense to me! I just don't know where to touch the test light. The aligator is hooked up to either ground or positive, but am I touching the right spot with the tip of the test light? See the photo I posted to see where I'm touching

What do you mean if I do the bottom one?
 
#13 · (Edited)
Kill switch in the off position? If so, there will be no power to the points. Also, the gap looks well over the .012" to .016" settings range. To answer your question about where to touch with the test light: if you have the wires, insulated washers and bolts/nuts to the points connections assembled properly, the spring on the points and the connector on each of the blue and yellow wires should be positioned outside of the fiber insulating washers so that they do not touch the metal "bodies" of the points assembly themselves (the part where the screws are that mount and lock position of the points to the plate). If that assembly is correct, the bolt holding the blue and yellow wires to the points will be the place you find power when the points open with the key and kill switch on. If there is no power to the points wires in that situation, either there is a connection issue elsewhere or the insulating washers aren't properly assembled on the points themselves, allowing the power from the coils to get shunted to ground. A closer, properly-oriented picture that zooms would help us determine the wiring and assembly better. To confirm, the test light should be clipped to ground for this method to work (as it is when connected to the head or cylinder fins, given that the grounds to the frame and engine are connected and clean and the battery is connected properly as well)
 
#14 ·
Make sure you have a good ground on the test light. Probe the positive side of the battery. It should light up. Then turn the ignition switch on. The black wires in the harness will be hot and should light up the test light. Then make sure the kill switch is in the run and the spring side of the points should be hot.
 
#16 ·
Early in this post I told Jeff the prob he was using wouldnt work and he needed a test lamp. Later on Jim Palmer said the prob was fine. Ive never used any thing but test lamps so I tried the prob and it worked. As the man said you can teach an old dog new tricks it just takes longer. Thanks for the heads up JIm

Bill
 
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