I don't understand the points of it all.

[1972_XS650]

Hi all, I recently bought a ‘72 xs650 as a project bike for the summer and when I have a chance to work on it, I’m finding so much has been changed on this motorcycle. For example, the right cylinder was totally deleted. Meaning the points was missing and the wires from the points was disconnected and electrical taped on purpose for an unknown reason. The only reason that I can come up with is last week when I took apart both carburetors and cleaned them in the ultrasonic cleaner, checked every part and found out the diaphragm had a small hole in it possible reason I don’t know. (Super glue fix preformed for now) I bought new points for both cylinders connected all wires checked all other wires. Everything is getting power as it should.
I am now trying to get the points in order. I have a service manual and I set the gaps on the points as they should be. I’m now trying to do static timing on the engine that I saw on YouTube. The bike runs way too rough and does not idle at this time. So I thought doing static timing first just to get the bike running correctly as possible before I use a timing light. Well, I found out that the points are not opening and closing when they’re supposed to. They are exactly 180° off. Please check pictures. My question is why is this happening? What can I do to fix that? Am I doing the test right in the first place?

My setup to test when points are opened or closed.
Points open or not touching the light is supposed to be on. When closed or touching the light is off.

Picture #1

Picture #2
Timing mark you can see poking out a tiny bit 180 degrees. Just above the ratchet.

picture #1

picture #2

Light is off. And before asked, yes I rotated the engine all the way around multiple times to see if the light and timing markers would line up.

What would make it 180 degrees off?

Thanks!

 

[Jim]

Two main reasons it can be 180° out:
1. advance rod and mechanism (ATU) installed incorrectly...180° out.
2. Wires are swapped either at the points or the coils.

You can swap the two leads at the points. That will get you back to normal timing. To put it back "right" though, you'll need to check wire colors at the points and coil. If both of those are correct, it's the ATU. Just swapping the wires at the points will "fix" it for now though.

 

[Jim]

... and welcome aboard!!

 

[1972_XS650]

Two main reasons it can be 180° out:
1. advance rod and mechanism (ATU) installed incorrectly...180° out.
2. Wires are swapped either at the points or the coils.

You can swap the two leads at the points. That will get you back to normal timing. To put it back "right" though, you'll need to check wire colors at the points and coil. If both of those are correct, it's the ATU. Just swapping the wires at the points will "fix" it for now though.

Reason 1. ??? Please explain.

 

[1972_XS650]

... and welcome aboard!!

Thanks. Just know I’m going to have a lot more questions about the xs650 in the future.
FYI if you or anyone has a autobody or motorcycle paint question please ask. I’ve been autobody painter for 35+ years. I would love to pay it forward.

 

[Jim]

The ATU can be assembled 180° out and it will look perfectly normal just looking at it.

Bring the left cylinder up on compression stroke until the points just open. Tell us which points set opens and we'll know if the ATU is assembled correctly.
If it is, it should be the lower points set that opens.

 

[Jim]

Thanks. Just know I’m going to have a lot more questions about the xs650 in the future.
FYI if you or anyone has a autobody or motorcycle paint question please ask. I’ve been autobody painter for 35+ years. I would love to pay it forward.

I was doing painting for forum members at a "forum discount." I'm hangin' up my guns. Feel like jumpin' in?

https://www.xs650.com/threads/painting-tins-no-really.56271/

 

[Jim]

Here's a '72 tank I did in the Euro/Oceana colors.

 

[1972_XS650]

I’m looking at the bike now. I’m wondering about your reason #2 the wires are swapped.
If I take the yellow lead and connect it to the other point there is no difference. The light comes on at the 180 degrees point.

 

[1972_XS650]

I was doing painting for forum members at a "forum discount." I'm hangin' up my guns. Feel like jumpin' in?

https://www.xs650.com/threads/painting-tins-no-really.56271/

Why are you hangin up your guns? The tank looks amazing!
Are you or were you a autobody painter?

 

[1972_XS650]

And to answer your question, yes I’d be happy to jump in and help.

 

[Jim]

If I take the yellow lead and connect it to the other point there is no difference. The light comes on at the 180 degrees point.

Well yeah... if one's swapped, they both have to be. Try what I suggested before, bring #1... the left up on compression stroke and tell me which point set opens. Not worried about the light, we're just trying to see if the lower point set opens when the left comes up on compression.

 

[Jim]

And to answer your question, yes I’d be happy to jump in and help.

Then you can introduce yourself on my painting thread and maybe throw in some pics of your work.

 

[Jim]

Why are you hangin up your guns? The tank looks amazing!
Are you or were you a autobody painter?

I was into autobody when I was a kid. I'm almost 71 now and just don't feel like painting anymore. I still paint my own stuff, but that's about all I care to do nowadays.

 

[1972_XS650]

Well yeah... if one's swapped, they both have to be. Try what I suggested before, bring #1... the left up on compression stroke and tell me which point set opens. Not worried about the light, we're just trying to see if the lower point set opens when the left comes up on compression.

I’m working on dinner right now. After I’ll check.
Just to be sure on my part. Compression stroke is piston TDC and both valves closed. Right?
Remember, painter not mechanic.

 

[Jim]

I’m working on dinner right now. After I’ll check.
Just to be sure on my part. Compression stroke is piston TDC and both valves closed. Right?
Remember, painter not mechanic.

Yes, correct. Easiest way to check is to hold your thumb over the plug hole and feel for compression as you rotate the crank counterclockwise. After you feel compression, finish rotating to TDC and look and see which points opened.

 

[Jim]

A good idea since you're having timing problems is to watch through the plug hole for the piston stopping at TDC and look at the rotor. The timing mark should line up on the line just to the right of the T on the stator.

 

[1972_XS650]

Yes, correct. Easiest way to check is to hold your thumb over the plug hole and feel for compression as you rotate the crank counterclockwise. After you feel compression, finish rotating to TDC and look and see which points opened.

Looks like they are both closed.

 

[1972_XS650]

 

[Jim]

Well, if you're at TDC on the left cylinder (compression stroke), then it looks like your ATU is correct. You can see the lower points set is on the "ramp up" side of the points cam.... so that's a good thing.
It means either your points or coils have the wires swapped. Just off memory... I think it's the orange wire for the left side and grey for the right.