CSR1000 pickup coil magnets.

I was replacing the pickup coils on my 1981 csr1000 and I
didn't mark the magnets.I noticed a white dot on each magnet can anyone tell me which way the dot should face,either engine side or facing the pickups.Thanks.

First of all, it should not matter which way you install the magnets. Second of all it is very easy to tell which way they faced before you removed them. Take a look at the impressions in the face. The side facing the main plate will be uniform and have no impressions with the exception of the timing oval. The side facing the coil plates will have the impression of the coil plate. Especially visible at each end of the magnet. But one thing that IS IMPORTANT. Is that the screws you use are NON MAGNETIC. The original screws are brass. If you use regular steel screws, it will change the continuity of the magnetic field and will give an inconsistent spark.

Thanks for the info,I just read one time that if they were
mounted backwards that would reverse the polarity.I will use
the original screws,and check for the impressions in the magnets.Thanks again.

It matters. The dots are there for a reason. There should be stripes on one side of each magnet. If there are no stripes, assume the dots are in place of the stripes.

Incidently, I believe I figured out the stripe is magnetic north (using the right hand rule on a coil method of determining magnetic polarity).

I believe all the screws are steel with zinc plating. But notice the magnets are isolated from them with brass inserts in the holes.

EDIT:
I changed the page so the polarity can be confirmed through using a voltmeter instead of using the stripes/dots as the polarity test.
Details here:
home.comcast.net/~loudgpz/GPZweb/Ignitio.../PickupAndRotor.html

I now have 12 sets of pickup coils. Every set has BRASS screws holding the magnet plates down. I checked six different pickup plates and all but one had stripes some were facing to the back plate and some were to the pickup plates. I looked at each set before disassembly with a magnifier to see if the screws were virgin (not removed)previously. These screws were never intended to be removed in the first place since the individual parts are not available separately. I inspected each magnet very carefully for plate depressions to determine if it was factory installed that way. Some were stripe and some were stripe out.

ah yes, you are correct. The magnet plate screws are brass. What threw me off is the washers on them are steel.

The pickup mounting screws are steel.

In order for the pickups to work, each magnet must have the same pole facing the timing plate. If one has north facing the plate and one has south facing the plate, the two fields will semi-cancel and the overall magnetism is weaker.

Also, if you flip the poles, then the polarity is reversed. That is ok if you also flip the wire polarity. (Just like humbucker pickups on a guitar... one half of the pickup has magnets and wires reversed so the signal from each half is still in phase, but the hum from RF will be out of phase. Reversing the wires cancels the hum, but reversing the magnets allows the signal to remain in phase with the other half of the pickup.)

If you check the magnets it should be easy to tell which ones are different. If they stick together stripe to stripe, then they are opposite polarity magnets. I only checked about 4 or 5 sets from 550's in the '81 to '84 range. Maybe they made some with opposite polarity, seems unlikely though. On all of the ones I've checked, the center core of the pickup is a south pole, which makes the reluctor rotor a north pole. This is why the signal goes positive when the rotor approaches and negative as the rotor moves away (based on black and yellow being the positive wires).

Also, it doesn't matter which way it rotates, just whether the rotor point is approaching or receding. Therefore, by flipping the rotor, you can invert the duty cycle to get longer dwell, but the signal becomes less stable that way.

I think one reason I researched the actual details of the magnet polarity was because I got some used ones on ebay that were assembled wrong. I probably found the coils were good but the pickups didn't work quite right.

I just checked the polarity vs. markings on a couple of the magnets. While the polarity position was the same between all of the plates, the markings are reversed. What this means to me is that the markings mean nothing. I would just follow the indentation marks in the magnets and you cant go wrong. And YES I do agree that if one magnet is placed up side down from the other they will cancel each other out and all will be Kaput.

Anyway I looked for the markings on the magnets where the pickup plate was located.They were pretty easy to see so I
just installed them according to the marks and its working fine.
Thanks again for all the input.

That it is working is the most important.

That it is working is the most important and is really the only thing that counts.

Well that's odd. I guess marking can be made wrong, but on the dozen or so magnets I have they are marked white stripe as north. I'm only checking the smaller 550/650/750 pickups, though.

As i said in the webpage, if one magnet is flipped, but the stronger one is in the correct way, it may still work ok, but the signal will be weaker. Probably just harder to start.

If both are flipped, the bike will still probably run, or at least start, but the timing will be off.

Those are the symptoms to look for.

To test the magnets, you put them flat-to-flat. If they repel, the two sides facing each other are the same pole and they should both face down or both face up. To check, if it's right, you can look at the timing with a strobe light.

If someone assembled it wrong and it sat on a shelf, the indentation markings may be the same on both sides. I believe I have at least one magnet like that somewhere.

Since there are some magnets with reverse marking, then we can't use that as the test. I'll devise a new test involving a voltmeter and do a write up on it.

EDIT:
I changed the page so the polarity can be confirmed through using a voltmeter instead of using the stripes/dots as the polarity test.
Details here:
home.comcast.net/~loudgpz/GPZweb/Ignitio.../PickupAndRotor.html