Author Topic: dwell questions  (Read 6808 times)

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Offline TwoTired

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Re: dwell questions
« Reply #25 on: August 09, 2013, 01:53:51 PM »
or 47.97 degrees
I disagree.  That might be a dwell meter's calibration value for point cams with multiple lobes, firing a single coil 4 times for every 720 degrees of crankshaft rotation.

But, a dwell meter that indicates 47.97 degrees of crank angle on the SOHC4 is lying to the operator.  That representation is only meaningful if the operator interprets the indication.
Put a degree wheel on the crankshaft, and note the degrees that the points are closed.  That is true dwell, and not some electrical circuitry's interpretation of a half speed, multiple cycle firing time distributor cam.

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 Reganator

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Re: dwell questions
« Reply #26 on: August 09, 2013, 02:23:01 PM »
Somebody isn't going to like this, but screw it, sayin it anyway.

For my 750 I've found that the tolerances from the manufacturer on the points and plate are off enough that rather than mess with feeler gauges and dwell meeters and the such I just set my points using a multimeter and my bike runs great.  I'm sure my dwell is on the high side, so I'll see how the coils fair, but the coils on there are old as dirt and are doing fine as is.
Frankenbike CB750: 
71 K1 Frame
72 K2 Engine
75 F0 Carbs:
     #40 slow jets
     #105 Main Jets
     Stock needle and settings.
My-neighbors-love-me-Kerker 4 into 1
Stock airbox

The best way to make a small fortune on the stock market is to start out with a large fortune.  Trust me, I'm an actuary.

Offline Bootlegger56

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Re: dwell questions
« Reply #27 on: August 09, 2013, 03:37:42 PM »
My seat of the pants aint calibrated enough to note the difference between setting the points with a carefully used feeler gauge and the timing with a digital meter set on continuity.  The only reason I use the digital meter is because it buzzes at me until contact is broken.  That way I can just close my eyes and rotate the engine, see where the marks fall and adjust accordingly.
Ya can travel near or ya can travel far; but no matter where ya go thar ya are!

750 K5
550 K1

Offline Reganator

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Re: dwell questions
« Reply #28 on: August 09, 2013, 04:14:20 PM »
Sounds like I'm doing the same thing as you bootlegger.  At some point I figured out that my bike ran just as well if not better and I saved a bunch of time and hair pulling by just using the continuity setting.
Frankenbike CB750: 
71 K1 Frame
72 K2 Engine
75 F0 Carbs:
     #40 slow jets
     #105 Main Jets
     Stock needle and settings.
My-neighbors-love-me-Kerker 4 into 1
Stock airbox

The best way to make a small fortune on the stock market is to start out with a large fortune.  Trust me, I'm an actuary.

Offline TwoTired

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Re: dwell questions
« Reply #29 on: August 09, 2013, 05:54:49 PM »
...rather than mess with feeler gauges and dwell meeters and the such I just set my points using a multimeter and my bike runs great. 
;D ;D ;D
...As far as you know.   ;D ;D ;D

Fark, it's your bike.  If you don't give a rats bum about how well it can run or how efficient it can be, I don't care either.  My guess is that, how it is supposed to work and be adjusted is beyond your comprehension, so you just made something up that the bike didn't puke on immediately.  (The design IS quite robust!)

Anyway, the info here is for those that DO care to do things that are best for the bike, rather than simply convenient for the present bike's abuser, er, owner.  So now I have to question, why you're on this forum at all?  Is it just a "social media" thing?

It's amazing what one can do with bailing wire, chewing gum, and random twiddles.  Lots of these bikes are just throw-aways, right?  So, who cares what's been done to them?

Historically, people are just too good for following a manufacturer's design recommendations.  (But quick to complain about the manufacturer when it breaks as a "lousy design").   But, just try making a million bikes with seat of the pants, willy-nilly adjustments, and also supplying a warranty.  There is a reason why you don't know any companies that do business that way.  They don't last too long.


Haven't we had a thread or two about ignorant and machine abusive P.O.s?    Perhaps we have a defender to add "rationale" for the P.O.s in absentia?   ;D ;D ;D
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 Reganator

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Re: dwell questions
« Reply #30 on: August 09, 2013, 06:13:09 PM »
...rather than mess with feeler gauges and dwell meeters and the such I just set my points using a multimeter and my bike runs great. 
;D ;D ;D
...As far as you know.   ;D ;D ;D

Fark, it's your bike.  If you don't give a rats bum about how well it can run or how efficient it can be, I don't care either.  My guess is that, how it is supposed to work and be adjusted is beyond your comprehension, so you just made something up that the bike didn't puke on immediately.  (The design IS quite robust!)

Anyway, the info here is for those that DO care to do things that are best for the bike, rather than simply convenient for the present bike's abuser, er, owner.  So now I have to question, why you're on this forum at all?  Is it just a "social media" thing?

It's amazing what one can do with bailing wire, chewing gum, and random twiddles.  Lots of these bikes are just throw-aways, right?  So, who cares what's been done to them?

Historically, people are just too good for following a manufacturer's design recommendations.  (But quick to complain about the manufacturer when it breaks as a "lousy design").   But, just try making a million bikes with seat of the pants, willy-nilly adjustments, and also supplying a warranty.  There is a reason why you don't know any companies that do business that way.  They don't last too long.


Haven't we had a thread or two about ignorant and machine abusive P.O.s?    Perhaps we have a defender to add "rationale" for the P.O.s in absentia?   ;D ;D ;D

I should know better than to feed trolls, but here goes:

First off, I don't think you know either the particulars of my bike or my experience setting points.  I also know you wouldn't have the stones to take that tone with me face to face, better men than you have tried. 

I happen to know the "correct" procedure for setting points and I opt for the one I use because it, and read this part twice just in case you are as dense as you seem, works better for my bike, and I'm not simply talking about a seat-of-the-pants measurement. 

Finally, there are entire threads devoted to the fact that some of these aftermarket parts do have lacking tolerances, and as such it can be ridiculously difficult if not completely impractical to set points using the "factory approved method."  Additionally, I actually understand the theory of how the ignition system works and I'll take that over a magic spell follow the procedure method any day of the week.

Anyway, I knew someone would show up crying about it, and here you are.  Wish I had been wrong about a certain member or two of the forum being so eager to be a smart-ass, but clearly I'm not.
Frankenbike CB750: 
71 K1 Frame
72 K2 Engine
75 F0 Carbs:
     #40 slow jets
     #105 Main Jets
     Stock needle and settings.
My-neighbors-love-me-Kerker 4 into 1
Stock airbox

The best way to make a small fortune on the stock market is to start out with a large fortune.  Trust me, I'm an actuary.

Offline TwoTired

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Re: dwell questions
« Reply #31 on: August 09, 2013, 06:36:16 PM »
Somebody isn't going to like this, but screw it, sayin it anyway.

And this wasn't the voice of a troll?  Or, just more youthful brash for it's own sake?

I should know better than to feed trolls, but here goes:

I guess you're trying to feed yourself.  Screw it.  Wallow in your own ignorance.  Anyone who wants to join you is welcome to what they get.

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 Reganator

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Re: dwell questions
« Reply #32 on: August 09, 2013, 06:42:29 PM »
I guess you're trying to feed yourself.  Screw it.  Wallow in your own ignorance.  Anyone who wants to join you is welcome to what they get.

A well running bike?

Also, you must not have read this part, so please read it again:

"I happen to know the "correct" procedure for setting points and I opt for the one I use because it, and read this part twice just in case you are as dense as you seem, works better for my bike, and I'm not simply talking about a seat-of-the-pants measurement."

So that's at least 5 times I've asked you to read that.  Here's 6, read it again.  Read it, know it, and understand it.  If you have questions, and clearly you would if you were actually interested in digging into how this stuff works, you should ask. 
« Last Edit: August 09, 2013, 06:46:32 PM by Reganator »
Frankenbike CB750: 
71 K1 Frame
72 K2 Engine
75 F0 Carbs:
     #40 slow jets
     #105 Main Jets
     Stock needle and settings.
My-neighbors-love-me-Kerker 4 into 1
Stock airbox

The best way to make a small fortune on the stock market is to start out with a large fortune.  Trust me, I'm an actuary.

Black 750K8

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Re: dwell questions
« Reply #33 on: August 09, 2013, 08:36:43 PM »
Time out everyone take a deep breath. Don't make me have to get up ;D

Offline lucky

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Re: dwell questions
« Reply #34 on: August 09, 2013, 10:00:58 PM »
IF you do not check the dwell the points could be gapped right but you could still have weak spark because the phonelic block that rides on the points cam is worn.
Or you adjusted worn out points which will give you a false setting of the points.
Just stating that the above comments are technically unjustifiable.

The block begins to wear upon the first revolution of the crank.  And so, will be "worn" soon after engine start.   
The spark will achieve full power if the dwell or accurate gap (jagged or not ) is properly set.  Proper dwell = proper gap= proper coil charge up time.  The dealership must have loved Lucky, replacing points for every serviced bike unsuspecting owners brought in.  $$$   This serves to prove that many dealerships were more interested in fleecing their patrons to the maximum amount to bolster their business, than to provide honest service.

I've been reconditioning points for years, without spark or run issues related.  Flat contacts give you correct feeler gauge gap AND dwell AND coil charge times.  It matters not if the points look like crocodile teeth, if the dwell is correct (as well as the effective gap), then so is the coil charge time and spark strength.

If you want to throw away parts with service life remaining, you are certainly free to do so.  It's your money, until you give it away.

"Just stating that the above comments are technically unjustifiable."

Use a magnifying glass and look at them.


The problem with points that have peaks on one side and holes on the other side is that the spark or release of energy can occur in the depth of the hole of the contact, or on the surface. Those peaks correspond to the holes.


Offline 74750k4

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Re: dwell questions
« Reply #35 on: August 10, 2013, 11:18:51 AM »
or 47.97 degrees
I disagree.  That might be a dwell meter's calibration value for point cams with multiple lobes, firing a single coil 4 times for every 720 degrees of crankshaft rotation.

But, a dwell meter that indicates 47.97 degrees of crank angle on the SOHC4 is lying to the operator.  That representation is only meaningful if the operator interprets the indication.
Put a degree wheel on the crankshaft, and note the degrees that the points are closed.  That is true dwell, and not some electrical circuitry's interpretation of a half speed, multiple cycle firing time distributor cam.

I agree, and here';s why! :)

Think of it as a Ratio. Ratio of Time closed vs. Time open at the points. Using your 360 degree example...
190/360 = 52.77% duty cycle. Closed 52.77% of the time, of a complete 100% revolution of the points cam, or 190deg of a 360 degree revolution. Don't matter.

52.77/1.1=47.97

If you take your 360 as 100% (multiply by .2778) = 100
and do the same to your 190 (multiply by .2778) =52.78 you're there!
Take a Duty Cycle reading with a DVM (those readings are 0-100, by the way) of 52.77 multiply by 3.6 you get 190...  multiply 100% by 3.6 = 360 it's all the same! Just different ways of expressing the same values!

So you are RIGHT! So am I...  be HAPPY!

Offline TwoTired

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Re: dwell questions
« Reply #36 on: August 10, 2013, 12:39:07 PM »
Use a magnifying glass and look at them.


The problem with points that have peaks on one side and holes on the other side is that the spark or release of energy can occur in the depth of the hole of the contact, or on the surface. Those peaks correspond to the holes.

So what?  That is a mechanical/visual observation without bearing on electrical function.  It is an electrical control device, and electricity doesn't care about peaks and valleys, only when it is able to flow or not.  And THAT is what controls coil charge time.

I do agree that once the craters and peaks form in the contacts, a feeler gauge is an inaccurate measurement device, unless you file off the peaks, at least.  The width of the valleys effect contact heating due to less contact area remaining.  But, you can file those flat.  Regardless, a dwell meter can still be used to set correct gap on used points, as it has direct relation to the coil charge time, which is half the purpose of the point contacts.

Perhaps you are referring to the spark you may see at the contact points, that is an event that occurs just after the points open, and has nothing to do with coil charge time.  That sparking occurs as the coils are firing the spark plugs.  It is an artifact of the coil's discharge behavior which is opposite the charge time or dwell.
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 74750k4

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Re: dwell questions
« Reply #37 on: August 11, 2013, 08:54:15 AM »
Sure is muddy in here :)

Hey, turns out using a test light/meter just might be a very accurate way to set your points after all! :)

Only one other item necessary, well maybe 2.

Install your test lead to the points and ground.
Install your Degree Wheel.
Observe the test light/meter, as you turn the crank with ign on. Make a note of the degree position on the wheel (or adjust for  zero)
Turn crank until the light goes out/meter shows zero.   Make a note of that reading. Determine the number of degrees you had to turn it.
Subtract from 360. That should be 190 degrees, or, adjust points as necessary to get there!
Here's the hardest part apparently...

Be nice!

Black 750K8

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Re: dwell questions
« Reply #38 on: August 11, 2013, 09:55:43 AM »
I still go with the dwell meter once I determine what my reading is with a new set of points with a very very careful round gauge setting. Mainly because it is easy plus the meter has a much better tachometer for other tuneup adjustments. Plus between tuneups if the engine starts running different I can look at the meter and quickly see if something has changed. To each his own.

Offline Reganator

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Re: dwell questions
« Reply #39 on: August 11, 2013, 01:34:35 PM »
Sure is muddy in here :)

Hey, turns out using a test light/meter just might be a very accurate way to set your points after all! :)

Only one other item necessary, well maybe 2.

Install your test lead to the points and ground.
Install your Degree Wheel.
Observe the test light/meter, as you turn the crank with ign on. Make a note of the degree position on the wheel (or adjust for  zero)
Turn crank until the light goes out/meter shows zero.   Make a note of that reading. Determine the number of degrees you had to turn it.
Subtract from 360. That should be 190 degrees, or, adjust points as necessary to get there!
Here's the hardest part apparently...

Be nice!

Like I said man, I get really really good results with this method.  As far as things going out of sync, I can do it so quickly I just reset them.  Takes maybe 30 minutes including taking the cover off, putting it back on, and grabbing my tools.
Frankenbike CB750: 
71 K1 Frame
72 K2 Engine
75 F0 Carbs:
     #40 slow jets
     #105 Main Jets
     Stock needle and settings.
My-neighbors-love-me-Kerker 4 into 1
Stock airbox

The best way to make a small fortune on the stock market is to start out with a large fortune.  Trust me, I'm an actuary.