Right Cylinder Timing

LikeyMeYommy

XS650 Enthusiast
Messages
44
Reaction score
27
Points
18
Location
Bloomfield Hills, MI USA
Hey Guys. Timing Adjustment question...

Did dynamic point adjustment w/dwell meter. Readings were 42 and 49. Adjust to 44.5 / 44.5. Running much better! You could hear it running better during the adjustment. Moved on to timing...

Had to re-adjust idle down. Seem it wanted to idle higher after the points adjustment.
I turned the idle screw all the way down (i.e. screw is barely touching the stop plate). Can't get it any lower than 1,230 RPM (according to both light and tach) which I guess I'm OK with.

Moving on to timing...
Have timing light. Left cylinder was way off to the left of the "F" mark (like an 1" to the left). Adjusted as much as I could and it's now slightly to the left (approx 3mm) of the "F" mark. Unless somebody tells me different, seems I could live with it but it is at the mechanical limit of the adjustment range.
Moved on to Right cylinder. Mark was like 1mm to the right of the "T" mark. Could not adjust it any further to get it over to the "F" mark.

Any suggestions?
 
Yes do sounds like it's sticking Not hard with a couple things you need to pay attention to.
 
Here's my advance assembly AS IS... should it be snapping back freely?

Do I have to take the whole thing apart to get the shaft out? Do I have to mess with the points side to get the shaft out? Trying to figure out how to remove/clean/lube.
 
The link shows splains it.
It depends where the points are on cam how well it will spring back but yeah that looks stiff .
 
To remove the advance rod, just take the little nut off the advance side and take that little disc off with the slots in it. Then you can pull the rod out from the points side, points cam still attached. You may have to lift the points sets rubbing blocks off the cam as you withdraw it because there's a lip around the back of it they may catch on. When you put it back in, there's an alignment thing you have to do or the timing will get thrown off 180°. There's a locating pin for the little disc on the advance side and one for the points cam as well. They need to point in the same direction. It's possible to assemble it with them pointing in opposite directions, 180° to one another, and that throws the timing off 180° .....

Advance Rod.jpg


The factory put slash marks on the disc and backing plate to help you get this right (yellow arrows) .....

Correct Advance Install.jpg
 
After adjusting dwell to 44.5, did you check the point gap with a feeler gage? I don't know why, but sometimes dwell specs and gap specs don't jive. Also, changing point gap to min or max of spec will make a big change in timing.
 
To remove the advance rod, just take the little nut off the advance side and take that little disc off with the slots in it. Then you can pull the rod out from the points side, points cam still attached. You may have to lift the points sets rubbing blocks off the cam as you withdraw it because there's a lip around the back of it they may catch on. When you put it back in, there's an alignment thing you have to do or the timing will get thrown off 180°. There's a locating pin for the little disc on the advance side and one for the points cam as well. They need to point in the same direction. It's possible to assemble it with them pointing in opposite directions, 180° to one another, and that throws the timing off 180° .....
The factory put slash marks on the disc and backing plate to help you get this right (yellow arrows) .....
This is EXACTLY what I was looking for. Thank you very much, again!!! I’ll let y’all know if this fixes my timing adjustment issue…
 
If your idle won't drop any lower with the idle speed screw backed all the way off, most likely your carbs are out of sync. One butterfly plate has closed all the way but the other remains open. Once that one plate is closed, the idle speed screw won't lower the speed any more.
 
After adjusting dwell to 44.5, did you check the point gap with a feeler gage? I don't know why, but sometimes dwell specs and gap specs don't jive. Also, changing point gap to min or max of spec will make a big change in timing.
The gap on the points is what determines your dwell... dwell being the amount of degrees the coil is charging.
A manufacturer will give a point gap that will get you close to (approximates) this dwell angle. Using a dwell meter to nail it exactly is the preferred method.
There's no need to go back and check the points gap afterwards. It'll likely be off slightly from the book value.
If you reset it back to the book gap, you've just lost the work of getting the dwell exact.
 
OK... observed something. Do your springs on your Advance rotate your shaft all the way home? Mine do not. It leaves it maybe a degree shy of rotating all the way home. Also the spring on the left (in the video) does not have ANY tension on it when I manual rotate the shaft home (it's loose). If it doesn't go home when engine is Off, how could it go home when engine is On (spinning)? I wonder if this is my timing problem.... weak springs???

 
Did you clean and grease the advance rod yet? I ask because it still looks like it's turning stiffly. Many times, the springs are a bit sloppy and loose at full retard but if the advance rod is well lubed and rotates freely, it doesn't seem to hurt anything.

Also, it looks like your little disc is installed wrong, 180° off. Many times, when guys assemble it wrong, instead of fixing it they simply switch the points wires. If the bike runs as is, then that's probably what has been done. But, it's not the right way to do it and may get confusing in the future for you or the next owner. On the points plate, the top set of points is for the right cylinder (marked with an "R") and should have a gray wire connected to it which then runs to the right cylinder's coil. The bottom points set is for the left cylinder (marked with an "L") and should have an orange wire connected to it which runs to the left cylinder's coil .....

650Points3.jpg


And I meant to ask - do you have an actual 2 cylinder dwell meter? I've never seen one of those and have had to use one with a 4 cylinder setting. When using the 4 cylinder setting, you must divide the actual dwell value (88°- 98°) by 4. This gives a reading range of 22° to 24.5°. Dividing it by 2 would give the range you're working in, and why I'm asking about your meter.
 
I did clean and lube the shaft. My thought is if the spring is literally loose at full retard, then theoretically only one spring is responsible for getting it all the way there. Are the 2 springs supposed to be identical?

Valid question about the dwell meter. My meter has options for 2-12 cylinder. I did test on the 2 cylinder.

I'm perplexed about the disc. I see what you're saying. Marks are 180 off. In my partial defense, I put it back together the exact way it was (LOL)! But the keyway in the shaft needed to be lined p with the key hole i the disc. Should I have reinstalled the shaft 180-degrees? My next question is how is this thing running? Is this part of my timing problem? Orange and Gray wires appear to be on the correct points.

IMG-5938.jpg


IMG-5937.jpg
 
OK, orange and gray wires are connected properly at the points, but which coils do their other ends connect to? Also, then which cylinder does each plug wire run to? It's possible to switch things up at the coil connections, or by which cylinder a coil's plug wire runs to.

If you timing was 180° off, I don't think the bike would even start.
 
So, does your advance rod turn easily by hand now and not "stick" at certain spots? Yes, sometimes the springs do get weak but as I mentioned, a well lubed and easy turning advance rod usually still works fine with loose springs, returning to full retard. But, you can shorten them to make them stiffer. You cut the "hook" off one end and bend the next spring loop out to make a new hook. Only do this to one end of the spring, and only to one spring. That's often enough to fix the issue. Obviously, do the spring that's loose. You can over-do it and make things too stiff, then the advance won't advance. That's why you only do one spring to start with, test that and see if it's enough.
 
I mean it's pretty smooth but I wouldn't say it's like butter, but I'm trying to rotate this shaft with my fingers twisting it by the threads. I would not say it rotates easy and smooth. It takes a little bit of work and again is not like butter smooth. Kind of hard to describe…

Now I just removed and cleaned the rod. I guess I'll remove the entire advance unit today and try clean and lube it up better. Any benefit in taking the points assembly off?

RE the wiring, sounds like I'd have to take the tank off to get at the coils? Are there 2 coils. Left is left cylinder, right is right type deal?? Any chance I can do a continuity test from the points to the plugs?
 
re L- R If it runs you are good, f'getabout it.
The points rub blocks going up and down the points cam ramps change how freely the rod rotates.
You got a timing light? watch timing as you idle, slowly rev, back to idle a few times. Does the timing move slow and smooth? Set timing at full advance, check both sides, if the idle time is still in range you're done.
 
Back
Top