Author Topic: Point Setting  (Read 6570 times)

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Offline surein

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Re: Point Setting
« Reply #25 on: October 18, 2011, 07:05:09 PM »
That's exactly what I did. I went about 60 to 90deg from the 1.4 mark and made the left gap .014, then I rotated 180deg and made the right gap .014. When I checked static timing it fired at the 1.4 mark instead of the F. I rotated the plate to retard but it still fires before the F mark.. I will recheck this routine again tomorrow

Offline Spanner 1

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Re: Point Setting
« Reply #26 on: October 18, 2011, 07:23:56 PM »
But, but, but !.... if you set 1-4 gap and then rotated the cam 180 degrees, you have way passed the 2-3 point max. opening... the points are not 180 deg. apart.
Try this; turn the cam to open point 1-4 to it's max. opening. Set the gap @ 14 thou. Mark this place on the cam with a Sharpie marker right at the point 'shoe' ( that rides on the cam ). Now rotate the cam until the Sharpie mark is under the 2-3 point shoe.... see? , it's not 180 deg, more like 90 deg. +/-
So, with your Sharpie mark now under 2-3 shoe, set the 2-3 gap to 14 thou. Setting the point gap and timing the motor are two separate items. Forget about F marks when setting the point gap, has no relation until gaps are set as described, THEN turn cam to 'F' mark and adjust plate ( turn it ) until points are just opening........
« Last Edit: October 18, 2011, 07:31:30 PM by Spanner 1 »
If your sure it's a carb problem; it's ignition,
If your sure it's an ignition problem; it's carbs....

Offline surein

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Re: Point Setting
« Reply #27 on: October 18, 2011, 07:34:57 PM »
I'm confused: HM in his book clearly states to turn crankshaft 90deg past the 1-4 mark to set the left gap then turn 180deg to set right gap

Offline Spanner 1

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Re: Point Setting
« Reply #28 on: October 18, 2011, 07:48:35 PM »
Yep, correct.... if the max. place on the points cam is 90 deg. past the 'F' mark ( sounds right to me ) , then the max. place on the points cam for 2-3 will be 90 deg. more, or 180 deg. TOTAL rotation  ;), not 180 deg. from the place you have set the 1-4 gap...
If your sure it's a carb problem; it's ignition,
If your sure it's an ignition problem; it's carbs....

Offline surein

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Re: Point Setting
« Reply #29 on: October 18, 2011, 07:58:05 PM »
I quote: "Turn crankshaft (always to the right) until it is 90 degrees past the "1-4" mark, then set 1-4 points gap (left set) with gage. Turn engine 180 degrees from here, set 2-3 points (right side) the same gap."

Now how did I mess that up? it states to turn 180 degrees from here (which is 270 degrees from the 1-4 mark).

scratching my head..

Offline Spanner 1

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Re: Point Setting
« Reply #30 on: October 18, 2011, 08:10:28 PM »
Oops!... had my numbers wrong !... yes, 1-4 and 2-3 points are 180 deg ( 1/2 turn of the cam ) apart, so gap setting as HM describes would be correct !
If your sure it's a carb problem; it's ignition,
If your sure it's an ignition problem; it's carbs....

Offline surein

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Re: Point Setting
« Reply #31 on: October 18, 2011, 08:16:05 PM »
*phew* thanks Spanner.
I'll try to static time as per the manual again and hopefully I won't run out of plate rotation.

Offline jonboycox

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Re: Point Setting
« Reply #32 on: October 18, 2011, 08:18:54 PM »
There is a way that you ran out of rotation on the plate. The same thing happened to me exactly. The points I have are identical to the original off of the bike, minus the pitting of course. From talking to a professional motorcycle mechanic as well as lots of research on the internet you have two options if this occurs. One is to do as I did and reset the 1-4 gap slightly so that when the 1-4 timing is set the sub-plate has enough room to achieve proper timing on 2-3. As long as the gap on 1-4 is within the range set out in the manual, the point should only receive the normal amount of wear. If the points must be set outside of this range to achieve proper timing on the 2-3 plate then that is bad news. It was suggested to me to then take off the sub-plate and and elongate the adjustment slots with a round file. Take a good look at the points before they go on the bike. Make sure that the contacts touch completely with no light coming through. You may need to tweak them slightly if they where handled poorly before they got to you. These parts are not robust, and can get out of alignment easily. Also, after every time you mess around with the points you should be sure they are free from dust, dirt and grit. It was suggested to me to take a clean piece of thin cardboard and open the points with your fingers, place the cardboard between them, let them close then wiggle the cardboard around. Open the points with your fingers to remove it. This will get rid of any crap in there. Keep on fiddling, its the only way to learn.

Offline surein

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Re: Point Setting
« Reply #33 on: October 18, 2011, 08:33:28 PM »
Thanks jonboy.  I knew someone out there understood me LOL!
I got the Japanese Daiichi points - hope this is not the root of evil.


Offline tanman855

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Re: Point Setting
« Reply #34 on: October 18, 2011, 09:49:10 PM »
Does anyone have experience with any of the solid state ignitions?
1974 cb750 (cafe in progress)

Offline TwoTired

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Re: Point Setting
« Reply #35 on: October 18, 2011, 09:53:22 PM »
You CANNOT adjust points that have pitting!!
Yes you can, and quite accurately with a dwell meter, (which doesn't give a rat's butt about pits and valleys).

Once the points are pitted(usually for being too small of a gap or leaving the key on. They are ruined. But you want the gap to be the minimum.

Filing or sanding the pitted points contacts surface will also not improve them.
I agree sanding ruins them due to embedded particles (sand), but filing does not.  Been doing that for 20 years, and I have point sets that are that old and reconditioned at least 10 times.

Matter of fact they will be worse.
Only if sandpaper was used.  Otherwise, they work as new (assuming proper adjustment).

Also try to use a multimeter analog with needle to set your points NOT a light because with a test light by the time the light lights up the amount of resistance that that takes will make the timing late. Use the multimeter and set it on the ohms x1000 scale. As soon as the needle jumps it means the coil has fired.
What !!??!?
I double dare you to actually measure the difference in real time.  I look forward to your post of this data.
It will be lost in the noise of human reaction time.
Further, to use the ohms scale effectively, you will have to disconnect the coils from the points as they are both connected together at the power source.

See what happens is the points start to open and the condenser is storing that energy(micro farads) and not allowing it to be released to the coil until the gap is at the right amount.
No.  You'd best review how this Kettering type system works.

The coils store all their energy when the points are closed (dwell time).  When the points open, the coil's primary electromagnetic field collapses generating power in the coil secondary windings to create an arc at the spark gap.

The collapsing primary magnetic field also generates a voltage in the primary winding, too.  The condenser absorbs some of this "back EMF" surging back to the opening points, and reduces the current and voltage peaks that develops across the opening points.  This reduces the heat generated at the point contacts, which reduces pitting.

The condenser ALSO helps the coil magnetic field to collapse more rapidly, as it makes the current rise faster than a coil does.  In capacitors current leads Voltage.  With inductors, Voltage leads current during a change in power.  (The trade schools teach ELI the ICE man, to help remember how these things work.)

Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline TwoTired

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Re: Point Setting
« Reply #36 on: October 18, 2011, 09:55:09 PM »
There is a way that you ran out of rotation on the plate. The same thing happened to me exactly. The points I have are identical to the original off of the bike, minus the pitting of course. From talking to a professional motorcycle mechanic as well as lots of research on the internet you have two options if this occurs. One is to do as I did and reset the 1-4 gap slightly so that when the 1-4 timing is set the sub-plate has enough room to achieve proper timing on 2-3. As long as the gap on 1-4 is within the range set out in the manual, the point should only receive the normal amount of wear. If the points must be set outside of this range to achieve proper timing on the 2-3 plate then that is bad news. It was suggested to me to then take off the sub-plate and and elongate the adjustment slots with a round file. Take a good look at the points before they go on the bike. Make sure that the contacts touch completely with no light coming through. You may need to tweak them slightly if they where handled poorly before they got to you.
You could also look in the ignition FAQ about shimming the main plate during gap setting and timing adjust.
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline phil71

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Re: Point Setting
« Reply #37 on: October 18, 2011, 11:39:17 PM »
Holy crap this is nuts . Points adjustment is not a matter of opinion, but empirical data . This thread has occupied enough time to set the points on 25 inline fours. What's the threshold for wasting what's left of the season futzing or just paying a pro for a half hour of his time .

Offline surein

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Re: Point Setting
« Reply #38 on: October 19, 2011, 04:27:07 AM »
Holy crap this is nuts . Points adjustment is not a matter of opinion, but empirical data . This thread has occupied enough time to set the points on 25 inline fours. What's the threshold for wasting what's left of the season futzing or just paying a pro for a half hour of his time .

I agree - sorry to burden you guys but I wanted to start learning the little things and all the idiosyncrasies pertaining to these old bikes.  There's a wealth of info in the forum - perhaps even more so than my local mechanic.

Thanks TT for filling in the gaps


Offline surein

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Re: Point Setting
« Reply #39 on: October 20, 2011, 05:25:15 PM »
Just want to finish off the thread with this bit info I found:
http://forums.sohc4.net/index.php?topic=59886.0

It's my Daiichi points afterall