dual points adjustment?

what is the correct way to adjust the points on a 1972 xs650 how will i know is it is top dead center?what is the setting .016

gap or timing? i always use a timing light if the bike is running.

You set the points gap at .016" when the point cam is at its highest spot and the points you're adjusting are opened farthest. That spot can be hard to see, just spin the motor a few times and watch the points arms move to find it.

Be sure you feeler gauge is clean, the slightest oil on those points will foul them. If that happens give them a quick blast with a quick flashing solvent like brake cleaner or electrical contact cleaner. The lube the sponge pads with a drop or two of motor oil.

Once the gap is set, disconnect the point wires where they connect to the coils under the gas tank. Connect one wire to a multimeter lead, ground the other lead, set it to resistance or continuity checker. Pull the left side alternator cover and turn the engine counterclockwise with a 17mm wrench. As you turn it that cylinder's points should close and you should see 0 ohms or hear the beep. When the alternator line hits the "F" range just before T the points should barely open and the resistance on the meter should go to infinity or the beep should stop. If it doesn't, loosen the adjustment screws and turn the whole contraption to adjust the timing. Set the giant right side points dial first with the big screws, then adjust the bottom points for the left side. The crankshaft and cam shaft both turn counterclockwise(as viewed from the left side) so to advance the timing(fire earlier), turn the points dial clockwise.

Now repeat this process for the other set of points. You use the same mark on the alternator...the crankshaft goes round twice for one turn of the cam.

The top points should fire the right cylinder, bottom should fire left. If you want to double check this, pull off one of the valve covers. The cylinder that firing should have its camshaft lobes pointed down and the rocker arms should be loose. It's worth noting that if you install the advance rod upside down the points will be backwards, but still run as long as you wire it backwards as well.

Once you've used this method to get the timing close, you can crank the bike and use a timing light set the timing perfectly. Well, never perfectly, but as long as both sides are firing in the "F" range on the alternator you're good.

The acceptable range is .012"-.016". As it runs the points gap will usually shrink from .016" due to wear. Or the points will get tiny holes in them that actually increase the gap more than the feeler gauge indicates. The only way to know exactly is with a dwell meter, but that's another story.

Here's more info with pictures:
http://www.650motorcycles.com/points.html

After you get everything close, be sure to go back and check your points gap again. These bikes have a lousy points system, all the adjustments can wiggle around in every direction making it a real pain to set them up. If you can't get the timing within the range, your point rockers may be worn too much or there may be even too much slack in the timing chain. Just keep adjusting and checking and eventually you'll either get it right or break down and buy pamcopete's electronic replacement ignition, haha: http://www.yamahaxs650.com/

To be honest, the only reason I haven't gone electronic is I'm cheap, stubborn, and like to be able to pull a spark plug wire while I'm tuning without worrying about frying electronics.

I've got a question, sorry for the thread revival but it's applicable here. I've followed the steps in this thread at at the link below. I set the gap for the right cylinder, upper set of points, and went to check with a 12v test light that I had power and the power was on at the lower points and not the top. Is this right? Seems backwards to me. If it is in fact wrong, what would my next step be?

Question to you. Are you asking what .016 means?

No, I'm asking why the directions that I forgot to link to...Fuck... says to set the gap on the upper points, and check for power there, but I don't have power there, I have power on the lower points.

The bike ran off both cylinders when I started to check the ignition so it was firing, all I did was loosen the point adjusting screw, set gap with my feeler guage, and no light when I check with my indicator light.


now I'll actually link the directions I've been following:
http://www.650central.com/fsetting_pointstype_ignition_on.htm

step 8 is where I'm stuck, I don't get a light at the right cylinder set of points.

It depends on where your other indicator light lead is connected, if it's to +12 no light when the points are open, if it's to ground, light when the points are open if the points wire is still hooked to the coil. In the link he has not removed the point wire from the power (coil). So with the other lead to ground and the ignition on the light will be on points open. The only down side with this method is the other points are closed and their coil will get real hot because power keeps flowing to it. Some coils will give up a little cloud of smoke and die if left on too long. Yeah, I had a KZ305 coil actually give off a little mushroom cloud of smoke as it headed for the happy hunting grounds. They were kind of touchy about that.

I think I may have figured it out. THe directions aren't great for someone who's never messed with points before.

I should be getting spark at the gap correct? Which means that should take place on the compression stroke correct? Those aren't matching up, pulling the plug and putting my thumb over the cylinder to find compression has showed me that the points were long closed by that time.

Simply put, the ignition spark (at the plug) occurs when the points open. This should happen on the compression stroke, with the piston a few degrees before top dead center.

And yes until you have done it a few times setting points is touchy and misleading with the bolts a bit loose the timing and spark will move around and change one more time when you tighten them. That's why Pamco's are so popular. Also open the other side and make sure the advance springs are tight and the advance weights are fully retracted. Limp springs and sticky advance rods are VERY common and a Pamco won't cure either of THOSE problems. I'm working on my 79's timing right now. I snugged the springs and removed, buffed, and lubed the advance rod. Timing light for low and high RPM checks is next on the list.

Power at the point is what creates the spark at the plug correct? So I should be getting 12v power at the point when it's gapped. I'm not.

When the right cylinder point is gapped, i'm getting 12v at the left cylinder and vise versa.

Maybe I just need to find new directions and start fresh. Looking on youtube now.

I think you are confused but it's counter intuitive so don't feel bad. I stole this from auto zone then shortened it to match the XS650 system

power from the battery is fed to the primary circuit of the coil and is then grounded through the ignition points (the points are closed).
This produces current flow through the primary windings, which induces a very large, intense magnetic field. This magnetic field remains as long as current flows and the points remain closed.
As the cam rotates, the points are pushed apart, breaking the primary circuit and stopping the flow of current.
Interrupting the flow of primary current causes the magnetic field to collapse.

So when the points OPEN the spark jumps the gap.

As the magnetic field collapses, its lines of force cross the secondary windings, inducing a current in them. Since there are many more turns of wire in the secondary windings, the voltage from the primary windings is magnified considerably up to 20,000 volts.

As mentioned I am messing with my points today, it is very frustrating and I am very tempted to tear them out and install the Pamco I have. as soon as I loosen a screw enough to adjust, the timing goes wandering off. It is probably just stubbornness that keeps me working on the points. After I get it right I will ride it for a bit and then probably put in the Pamco and see what difference I get.

Yah, I'm getting more and more confused.

So I started with the top set at the right cylinder and cranked it CCW with a socket to where the point was at max gap, set it at .16 with a feeler guage. The next step is to hit it with a test light, so I take my light, (red alligator clip with black handle end) clip it to the positive on the battery and touch it to the gapped point, no light. Touch it to the closed point, light.

Is that how it's supposed to be? If so am I cool to go onto the next point and set it's gap? The directions I was following would be great with pictures or more descriptions. And I can't find a single damn video on youtube that's helpful

Ok, I think I got it. Thanks everyone for the help. It idles great now, starts first kick but has a some good hesitation at quarter throttle so now I think It's onto the carbs......yay /sarcasm

Carbs are my least favorite.

Trying to advise you really made me get into setting my points. I set both sides with a 12 Volt bulb so they were opening in the | F | zone. Then I jammed the advance weights out so the points cam was fully advanced. I checked the points opening again, they were opening 4-5 degrees BEFORE the advance timing mark. So I retarded the points plate til the points opened AT the advance mark. Test rode it 15 miles or so. Seems good but had a bit of break up in the 6500 to 7000 RPM area. I rechecked compression today and the RH cylinder is at 140 the Left is good at 155. The plugs looked good, coffee with cream not a throttle chop though just checked after I pulled it into the garage. I also put stock air cleaners back on and need to check which main jets I have in these carbs.
While I was at it I put a new gasket on the starter gearcase cover that had a slow drip, and changed the oil to 20-50 and checked and cleaned both oil filters. Then we went hiking and later horse back riding. What happened to the weekend?

I think the points gap is .016 not .16.
The Clymer book has a good how to with pics.
The factory book has a better how to and pics.
Gary, Grizld1 figured out how to correct the full advance timing by peening the tip of the fly weights that engage the disc notches. I don't recall the width he peened them too but I think if you peen them to a snug fit in the notches will be better. As long as they are not so snug they bind in the notches.
Leo

Mainly he is complaining about having to ride today.
The other part was he is to far advanced with the timing and retarded it abit.
So as to not burn a hole in the piston. That(a holed piston) would be one step forward and 4 back when you are trying to get going.

XSLeo, Retiregentleman gives a good description in this thread.
http://www.xs650.com/forum/showthread.php?t=11400&highlight=peen+advance+weights