Ignition or Carburetion?

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Moksha827
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Bikes: 56 Hydra Glide
Location: Maine

Ignition or Carburetion?

#1

Post by Moksha827 »

56 Hydra Glide Stock
Running a 6 Volt System, 2 brush gen, round style coil (Dual Tower)<<<<< I'll come back to this <<.
SU Eliminator II.

Been running it this way for 35 years without a hitch.
Couple years ago I was noting weak spark from coil, figured 35 years was pretty good service.
Replaced with aftermarket coil. Seems to work Ok, but begin to have popping and or missed ignition.

Tried two more coils and had some brief improvement only to go south again before warranty expired.
Have had an old timer bench test the coil(s) numerous times and never had consistent results with spark.
That is, never consistent between the two towers\secondary.
In fact, it is always the same (L) tower which throws a very weak spark.
Old timer is scratching his head now trying to figure out how 35 year old coil and 2 new aftermarket coils behave in this same manner.

In all of the posts and articles I have read there is never any mention of the "Dual Tower" coil configuration and whether or not there is a variable here that is being missed.
Polarity not an issue as far as I can tell.

Switch Gears>>>>> Carburetion question arises with popping and missed ignition.

Symptom: Acceleration from stop can be funky, not really a backfire from the carb, but more like sucking air and SU piston slapping.
Up to speed runs like a champ and sounds smooth.
As soon as I drop the throttle a hair and bring it back the nonsense starts again.
Rebuilt the carb, drained tank and replaced filter.
Seemed better for a bit and then its back.
So then I am back looking at the coil issue and begin to wonder if I am chasing my tail.

News Flash!!! The results are in, I am indeed chasing my tail.

Please weigh in with your thoughts, and I would very much appreciate any feedback on the "(L) tower which throws a very weak spark".
After 35 years of smooth sailing, this has really got me stumped.

Thanks in advance
58flh
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Re: Ignition or Carburetion?

#2

Post by 58flh »

Check the wireing from coil to breaker for any rubs, or corroded ends!---Replace the points & if its popping out the carb. maybe a bubbletest is in order!. Check ex. for leaks near the spigots. & just process of elimination.--If hyd. lifters are used check the ADJ. & lifters for scoring in the bores that might make them bleed-down fast. That carb. once set-up should run nice on a pan!--I think take your time & you will find the problem.----Richie---Ps---check points cam & make sure it opens the points to the same setting on each lobe.
steve_wood
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Re: Ignition or Carburetion?

#3

Post by steve_wood »

Assuming your coils are all non-supression, in other words, non-radio frequency interference, are your spark plug wires and spark plugs also non-supression? You can have problems if you mix and match.
john HD
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Re: Ignition or Carburetion?

#4

Post by john HD »

start with your condensor.

99 per cent of the time running misfires will lead to this one very inexpensive part.

-AND- do not assume a brand new one is good either! get a couple and try them -OR- test yours against a know good one and see what happens...

then move on to the other components one at a time. points, coil, carb, manifold.....

john
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