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Discussion Starter #1 (Edited)
Hey All,

So I was setting the static timing on my 73 T140 using the points ignition and I noticed that the left hand point ( with Yellow/Black timing wire) was not fully opening or really closing. It was moving in very VERY small increments when bike was running, and when moving the back wheel to manually set points it again was barley opening.

I should Preface, before when the bike was running I was getting some bad backfires and some mild smoke from the pipe and a little smoke out of where the headers connect, But ONLY on the left side. ( and when revving)

So what I decided to do was to switch the pointers ( not the wires ) and see if it was just a shot pointer ( nylon heel worn out) or if it was something to do with plate position ect.

I switched the pointers and it open and closed perfectly now on the left pointer side ( yellow/black ) But something interesting happend when I started the bike, it ran for a few seconds then stuttered out with some smoke out of the carb and pipe , I ran it again, and it did the same. But the last time , it started running, and sounded a little more healthy, but now the smoke (when revving) was coming out of the Right hand side header, not the left as before.

So my question is , Why is this happening? was I only running one cylinder properly and when i switched the points I burned up some excess gas? And secondly is there a way to fix the pointer problem or should I just buy a new one.

Thanks very much for the help!!!
 

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Hey All,

So I was setting the static timing on my 73 T140 using the points ignition and I noticed that the left hand point ( with Yellow/Black timing wire) was not fully opening or really closing. It was moving in very VERY small increments when bike was running, and when moving the back wheel to manually set points it again was barley opening.

I should Preface, before when the bike was running I was getting some bad backfires and some mild smoke from the pipe and a little smoke out of where the headers connect, But ONLY on the left side. ( and when revving)

So what I decided to do was to switch the pointers ( not the wires ) and see if it was just a shot pointer ( nylon heel worn out) or if it was something to do with plate position ect.

I switched the pointers and it open and closed perfectly now on the left pointer side ( yellow/black ) But something interesting happend when I started the bike, it ran for a few seconds then stuttered out with some smoke out of the carb and pipe , I ran it again, and it did the same. But the last time , it started running, and sounded a little more healthy, but now the smoke (when revving) was coming out of the Right hand side header, not the left as before.

So my question is , Why is this happening? was I only running one cylinder properly and when i switched the points I burned up some excess gas? And secondly is there a way to fix the pointer problem or should I just buy a new one.

Thanks very much for the help!!!
On the face of it this is a nutty problem. Altering point gaps and position will only affect timing, and has nothing at all to do with smoke. You have more than one issue confronting you, so deal with each separately.

If you can statically set these points up correctly for each cylinder, with the gaps consistent for both sets, then do so, provided the points themselves are in good condition.

If they are corroded or pitted, you can try to file this out, but some skill is required in keeping the points square, and to re-polish the surface again.

Most owners will simply replace badly pitted/corroded/worn points.

Despite the fact that artful static timing can be made very accurately, a strobe timing check is really pretty essential for any ignition system.

So, the object is to get the points operating perfectly, and a strobe of the timing is pretty much essential. The back firing and smoke are most likely other causes that you can attack when you're satisfied ignition timing is good. RR
 

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Discussion Starter #3
Thanks so much for the Reply!

Ah! That makes sense. I have the workshop manual, but somehow missed the info on the the eccentric screw needing to be adjusted.

Well that explains alot. I do have the TDC timing tool for the inspection plug.

So for clarification. I set both gaps at 0.015, at the marker on the cam, Then I use the tool to find TDC. Then rotate to BTDC and at this point my left point ( yellow/black ) should JUST be beginning to open? I then lock this in with the Pilar bolts. Then I rotate 360 degrees and set the right side points with the eccentric screw on the "secondary plate?

Hopefully this is the key!

Let me know if I am off on any of this.. and Im sorry for being new at this!
 

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Discussion Starter #4
On the face of it this is a nutty problem. Altering point gaps and position will only affect timing, and has nothing at all to do with smoke. You have more than one issue confronting you, so deal with each separately.

If you can statically set these points up correctly for each cylinder, with the gaps consistent for both sets, then do so, provided the points themselves are in good condition.

If they are corroded or pitted, you can try to file this out, but some skill is required in keeping the points square, and to re-polish the surface again.

Most owners will simply replace badly pitted/corroded/worn points.

Despite the fact that artful static timing can be made very accurately, a strobe timing check is really pretty essential for any ignition system.

So, the object is to get the points operating perfectly, and a strobe of the timing is pretty much essential. The back firing and smoke are most likely other causes that you can attack when you're satisfied ignition timing is good. RR
Yes I agree with the need to strobe!

The smoke was not so much of the problem as it was just interesting that it switched sides when I switched the points.

I hope that once I get the timing set the strange firing and little bits of smoke will go away as the timing is WAY off. haha

Cheers for the reply!
 

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Obviously the points need to open and close to make sparks.When you set the points gap to 0.015",you should get 160 degrees dwell.The points should stay closed for 160 degrees of cam rotation.
IF THE AAU IS BENT,AND HAS RUNOUT,THIS WILL NOT HAPPEN.
90% of AAU's are bent,cause peole knock them with a hammer to release and remove them (That should never happen).

I suggest you look at one point gap,and see how it varies around the high part of the cam.It should not vary at all,but 0.002" probably wouldn't matter.If it varies a lot,straighten the cam with an aluminium punch and a hammer.Loosen the centrebolt a little first,but leave it at least 1/2 tight.
Check the gap variation after you tighten the centrebolt again.

Then you can set both points to 0.015" gap.
Then check timing statically.With the timing mark aligned,you should only just be able to open the points when you force the cam fully clockwise (to the stop) against the springs.
Then double check the timing with a strobe light.Chances are that you won't need to adjust the timing .

Full advance should not happen below 2000 rpm.2500-3000 rpm is better.0.010" extra tension on the advance springs changes it about 1000 rpm.
 

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Then rotate to BTDC and at this point my left point ( yellow/black ) should JUST be beginning to open?
Good to hear Pete chip in with his usual good advice you need to heed.

I use a test lamp across the points to determins when the points begin to open. If one is fussy, you can get the points to where the light is just starting to glow dimly. This is the time to lock them up.

I recall from my youth we'd use a cigarette paper that would release just as the points broke contact. I prefer the lamp method though. RR
 

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I've never had to use a test light on the points.You can put the plug lead on a spare plug against the head.Watch and listen for the spark.
If you happen to be listening to the radio,just tune it between stations and turn up the volume.You'll hear a loud crackle on the radio,when the points open.
 

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Discussion Starter #8 (Edited)
Good to hear Pete chip in with his usual good advice you need to heed.

I use a test lamp across the points to determins when the points begin to open. If one is fussy, you can get the points to where the light is just starting to glow dimly. This is the time to lock them up.

I recall from my youth we'd use a cigarette paper that would release just as the points broke contact. I prefer the lamp method though. RR
Nice Cigarette Paper!..Haha I love the old school advice cheers for that.

Do I have to keep the AAU spun to fully advance while i am doing this?

Thanks for all who are chipping in this discussion!
 

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Discussion Starter #10
Thanks for the help guys! Got the bike timed and running better than it ever has! As for the smoking it disappeared.. So the mystery is over... for now!

Cheers to all you who contributed!
 
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