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Old 08-11-2014, 01:54 PM   #1
MacEntyre OP
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R75/5 Dynatec Question

I'm installing a Dynatec electronic ignition in my '73 R75/5 airhead... got a question, as the answer is not at all clear in the instructions.

When it says to crimp the pieces that hold the advance weights, to restrict the movement of the weights, is it for the purpose of preventing them from moving out with centrifugal force?

If so, mine will not restrict the weights by crimping. I can wrap a thin aluminum band around them, but crimping does nothing.

Asked another way... does the Dynatec electronic ignition depend on the mechanical advance?

Thank you!
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Old 08-11-2014, 02:53 PM   #2
Whiteguyphil
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Yes the Dyna system uses the mechanical advance system to advance the timing. Although the crimping was already done on mine, it was just bent down the middle. The reason is unclear to me, maybe someone else will chime in on that...
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Old 08-12-2014, 02:44 AM   #3
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Quote:
Originally Posted by Whiteguyphil View Post
Yes the Dyna system uses the mechanical advance system to advance the timing.
Thanks, Phil!

Mine will be completed today!
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Old 08-12-2014, 08:16 AM   #4
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near disaster!

Geez, I thought I was sunk when I saw one of the tiny springs missing from the mechanical advance...

Fortunately, Lee Spring is in GSO, and they had a replacement in stock.

Really dodged a bullet with that!
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Old 08-12-2014, 09:15 AM   #5
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I had to replace mine as well, The best tip I have for the DynaIII is to attach the sensor plate in the center of the adjustment play allowing room to advance or retard the timing. Then, use a test light (one end to ground the other to the ground side of the second coil), pull the spark plugs, place the gearbox in the highest gear and statically align the two sensors to the S mark. The test light method worked the best for me. I would have issues with ghosting using a multimeter or listening for the spark. Just be patient, and go around a few times until that light comes on exactly at the S mark while "bumping" the rear tire forward when you get near the timing marks.

Good luck.

When my timing is spot on and my carbs aligned, it rides smooth with little vibration and great throttle response (although, I have not ridden one with points )
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Old 09-08-2014, 06:03 PM   #6
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Quote:
Originally Posted by Whiteguyphil View Post
... pull the spark plugs, place the gearbox in the highest gear and statically align the two sensors to the S mark.
I put it in neutral and used the kick stater lever and the foot peg... I put the lever all the way down, let it up until one cog clicked, then pulled it down slowly by squeezing the lever and the peg together. About a dozen cog-clicks goes once around the flywheel.

I set mine so that it is just slightly advanced. The spark fires when the S mark is at the upper half of the window.

I need to get a timing light with an inductive pickup so I can check the timing while running, to see if the new springs on the mechanical advance are working properly.
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Old 09-08-2014, 06:42 PM   #7
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The crimping is done to keep the cam from moving back and forth. This locates the magnet in place. It probably isn't really necessary, but it can't hurt.

Always use a strobe-type timing light. This can confirm static and advance timing, as well as helping with diagnosis; intermittent flashing indicates a misfire.
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