Points Set-up

[gregwils]

Sorry to ask such an elementary question, but I don't feel like have found definitive information elsewhere. I use to change points back in the 60's and 70's, but they were all cars and lawnmowers.

My question where or not this is correct regarding the set-up left to right: nut, fiber washer, spring, points mounting plate, fiber washer, coil lead, condenser, nut. Thanks and if incorrect, I would appreciate the correct sequence.

[Jordan]

Not right as you have described it I think.
The spring conducts current, and should not be touching the points plate lug.
The spring, condensor and wire to the HT coil should be electrically connected to each other, and all 3 should be insulated from the points plate (earth).
There's a fibre sleeve to keep things from touching the plate lug.
Use a tester to confirm connections.

[gregwils]

Thanks Jordan.

I am going to interpret this as: nut, spring, coil lead, condenser, fiber washer, points plate, fiber washer, nut.

One quick follow-up. You say use a tester to confirm, do you mean a timing light? I am not sure what other test I might perform. Thanks.

[gregwils]

The coil lead and condenser are now connected to the spring side points plate, but still no spark using a spark testing light. Unfortunately, it's Sunday evening and I have to shift gears to start thinking about the work week ahead.

The battery has been charged, the coil has been tested, I replace the leads to the stator. The bike did run in my possession, so I know it has the capability, but I have somehow managed to accomplish a no-spark condition. A little frustrating, but it will keep working. Suggestions welcome, will respond as time permits. Thanks.

PS - This is a 65 250 Monza.

[Jordan]

There's a third fibre washer, which I called a sleeve in my previous reply. It's important, as it prevents the screw from making contact with the points plate hole. If you add that, your sequence should work (but I'd call the first nut a screw).
There should be a fibre washer either side of the points plate lug hole, and a smaller fibre washer within the hole. All the other parts can be placed in any order as long as they are on the "outsides" of the fibre washers (remote sides from the points plate lug) - they will then make electrical connection to each other, which is what you want.
Watch that the wire connection terminals don't touch the points plate, as they could do if bent over far enough. Some plain metal washers and a spring washer can be added, for a secure assembly.
If the small fibre washer is missing, you can probably make something with some plastic or fibre sheet of thickness no greater than the points plate lug.
A tester could be a multi-meter on resistance range, maybe with audible signal. Or, make up a lead with a light bulb and battery.
You want to confirm that the condenser, points spring, and coil wire are all in electrical contact with each other, and that there is no contact between these and the points plate lug.

[gregwils]

Thanks Jordan. I'm at work at the moment, but understand the need to isolate the points plate from any current. I do not believe that I have a 'sleeve' that would prevent the current from grounding against the plate. I will fabricate something, should not be an issue at all, then give it another go. I will update the thread later in the week. Thank you again.

[JimF]

Do you have a multi-meter? You could use it in the ohms or continuity setting (continuity would have an audible tone so you wouldn't have to look at the meter) to just get the points working.

To do this though you would disconnect the wire going from the points up to the coil as the ohm and continuity settings are not tolerant of voltage which your battery or alternator are putting on that wire indirectly.

Why do this? If you have your points plate and washers configured wrong then you could have (until you get everything correct) a permanent direct connection from that wire that connects to the coil to the engine/frame (this is the amperage return path back to the battery.) If this is the case the battery will drain quickly, and that drain will occur through the coil. Since you can't see amperage flowing from the battery through the coil, then through the points plate configuration, you could touch the coil to see if it's hot. Be careful, because it could be hot enough to give your fingers a good burn.

That's another reason you are better getting this straightened out with a multi-meter on a disconnected wire. The coil is meant to handle the amperage, but perhaps not constantly. When the engine is spinning, either by virtue of being kicked over or by running, the only time amperage flows is when the points are closed which is when the lobe of that eccentric cam is not pushing the small fiber block which then pushes the point's contacts apart. This means the contacts run open and closed (closed when the cam is not pushing the contacts apart) such that there is a time that amperage flows and a time when it doesn't. That's what makes the spark but the open points period also gives the coil a chance to cool a little.

Place your multi-meter in the continuity setting. If you have it right when you touch the test leads together you will hear a constant tone, and when you separate the test leads the tone will stop.

Connect one test lead to the wire that used to go to the coil. Connect the other test lead to the engine or frame.

When you have the points configured correctly you will hear the tone sound switch off when the cam lobe pushes against that fiber block which in turn opens the points, and as you rotate the engine the lobe will move, the points will close and the tone will sound. this will repeat as you repeatedly spin the engine.

Do you have a center stand? put the bike on the center stand and in gear, perhaps 4th gear. in this way you can watch the points work as you use your left hand to rotate the rear tire slowly and in turn rotate the engine.

When you get the points to opening and closing, you might then want to refer to Carl Liebold's excellent write up on setting the tming:

http://www.liebold.com/timing/timing.htm

Jim

[JimF]

My question where or not this is correct regarding the set-up left to right: screw, fiber washer, spring, points mounting plate, fiber washer, coil lead, condenser, nut. Thanks and if incorrect, I would appreciate the correct sequence.

If I recall correctly, there is a metal tab with a hole on it that holds the spring half of the two points plates. As you can see, the metal tab is connected to the engine which makes it "electrically" at frame potential.

You can also see that the other half of the points, the fixed point plate, is also connected to the engine with a metal connection making it electrically at frame potential as well.

The spring half of the points plates needs to be electrically isolated from the frame so that it does not conduct electricity when the point plates "open" (separate) by virtue of the cam lobe pushing the two points plates apart. So the problem is that the metal screw that secures the sprung points plate to the bracket will bring the sprung points plate to engine potential. We need to electrically isolate the sprung points plate but we need the metal bracket and screw to mechanically locate and secure the spring.

It's OK that the screw touches the spring - we want that to be one common electrical node.

So as Jordan points out, there is something that needs to go in the hole of the metal bracket that holds the sprung points plate to electrically isolate that metal points plate and the spring it's mounted on from the bracket. Look for either a non-conductive sleeve that would fit over the screw threads yet within the bracket hole, or perhaps one of your two fiber washers has a collar on it.

The collar or sleeve has to rest in the bracket hole so that when the nut passes through the bracket its threads will make no metal-to-metal (electrical) contact with the bracket. The second fiber washer keeps the condensor, coil wire and nut from electrically contacting the bracket. Although difficult to sequentially construct, this keeps the spring electrically isolated from the frame. The only way then that the sprung plate and mounting screw go to engine/frame electrical potential is if the points plate at the end of the spring touches the fixed points plate.

So I think your sequence should be "screw, spring, fiber washer with a collar which will face and drop into the points mounting plate, points mounting plate, fiber washer, coil lead, condenser, nut. " When you are done rotate the engine so that the cam lobe is under the fiber block. At this time the lobe and fiber block should be collaborating to lift the sprung points plate up and off of the fixed points plate.

Using your continuity tester check the spring mounted points plate for continuity to the engine and/or frame. There should be NO continuity. If there is continuity, loosen that rusty screw and slide the points assembly inward such that the points plates separate. Then tighten down the screw.

Rotate the engine to bring the cam lobe out from under the fiber block. The two points plates should touch, and a continuity check should indicate that the sprung points plate is electrically connected to the engine/frame. Bring the cam around again, slowing as you get to the fiber block. As the cam lobe pushes the fiber block check that the sprung plate looses its connection to the frame.

Now you have operational points plates. The next thing to do is to set the points gap, the gap that the lobe is creating, with a feeler gauge. Again, you will loosen the rusty screw and carefully adjust the gap using the feeler gauge resting between the points. Then re-tighten the screw and the points gap is set. Check it though, it usually takes a few tries to get it right.

Lastly you will have to set the timing of when the points open with relation to the piston's position on the compression stroke which is the subject of Carl Liebold's write-up.

Jim

[gregwils]

Jim,

Thanks very much for the detailed response. This is in response to your first post, haven't read the second yet. I do have a multimeter and can perform the test you suggest. It sounds pretty close to what you might perform with a timing light. I did time the engine, but what I can't explain is that my points connection were not correctly installed when I did it. They were as I described, not what Jordan provided which BTW is consistent with other sources of information that I subsequently found. The light never when entirely off when I was timing, just dim - the manual indicated that might happen (dim). I will try to grab a few minutes this evening to perform the multimeter test, not sure if my meter has a continuity test or not.

[gregwils]

Jim - Thank you for the second post. I follow everything. The sequence you listed below is the sequence of my points when I timed the engine. I did see a spark when I initially timed the engine, but didn't seem like it was sparking when I tried to start on another day. I am fairly confident that the bolt that connects everything is not isolated from the mounting plate, which would hose everything up. It actually sounds like if the bolt is isolated from the mounting plate, the lead and condenser connections could connect to either side.

So I think your sequence should be "screw, spring, fiber washer with a collar which will face and drop into the points mounting plate, points mounting plate, fiber washer, coil lead, condenser, nut. " When you are done rotate the engine so that the cam lobe is under the fiber block. At this time the lobe and fiber block should be collaborating to lift the sprung points plate up and off of the fixed points plate.

I will verify that the nut is isolated prior to performing any tests. Thanks again for this information.