350 NC timing

[ty_tk421]

Could somebody give me some instructions on the best way to set the ignition timing on a 350 NC? I have a manual but I'm struggling to get everything to fire properly. I'm either not doing something correctly or my set up is askew.

I'm working on an inherited 350 NC that was used for racing. It has a two spark set up from a single DynaTek coil & has an electronic ignition (I think it's a DynaTek but I'm not sure what model exactly). The alternator was removed & wiring is set up as a total loss system with a 12V battery.

Any and all help is greatly appreciated. Thanks.

[Duccout]

Tyler, we need a little more info! What exactly are you having trouble with? Assuming you have a degree disc set up and have found TDC? So we need someone who knows Dyna Tek ignition systems. Are there any marks on the pick up which tell you the full advance point?


Cheers,

Colin

[LaceyDucati]

Is the original mechanical advance being used? If not I think it will be fixed ignition, not an issue for a race bike, but no use if you are trying to use a kickstarter. If the advance mechanism is in use then time it statically 5 to 8 degrees as you would a set of points. If not in use, time it at full advance at 33 to 36 degrees.....then bump start it.

Nigel

[ty_tk421]

I did set up the degree wheel and got TDC. I don't have any markings to tell where I'm at full advance- I'll have to do a little trial and error. Appreciate the help. What are your recommendations on test light set up? I'm familiar with using a test light on my Honda twins but they're all running mechanical points, so I'm out of my element here.

Thanks again.

[Jordan]

When you know the number of degrees you want for the ignition timing, you can use a circular protractor with a hole made in its centre.
Mount it to the left end of the crankshaft, after removing the 8mm grubscrew and replacing it with required bolt, spacers etc.
Mark another line (on some masking tape on the clutch cover), measuring from your TDC mark.
That will do for static timing (engine not running).
You can alternatively not make another mark on the clutch cover, instead read directly from the protractor.

For timing a running engine, something similar but more robust needs to be made.
I could describe my home-made disc, with has a keyway to lock its position on the crankshaft.

If the pickup sensor is a Hall Effect type or optical type (both recognisable with 3 conductors), then you can use the same timing light for static ignition timing, as you have been using for points type ignition.
If the pickup is an inductive type (with 2 conductors), you need to use a strobe light with the engine running, triggered by the spark plug lead.

[LaceyDucati]

The Dyna systems I've seen are just large hall effect switches that replace the points, hence the no electronic advance. There should be lines on the rotor and switch that are aligned when the engine is set to the required advance on the degree disc. Theoretically where it is set is where it will fire when running and unless it has a mechanical advance that's it. Some photos of the system would help identify what you have, I'm assuming it's a modified Dyna S from a 750GT as I've never seen a specific system for a bevel single....certainly not one listed.

Nigel

[ecurbruce]

Hi Tyler,
Here's what I did for my two wire inductor timing setup, you may be able to do a similar thing. With this setup, use a spark plug triggered timing light directed at the protractor to see the degrees of the pointer (engine running,)
viewtopic.php?f=3&t=2308&p=17232&hilit=Timing+light#p17232

Good luck,
Bruce

[ty_tk421]

Attached is a picture of what I'm working with- not sure if it will reveal any other information. I was able to find out that it's a DynaTek DS6-1 that is meant for Harleys (not sure how/why my grandfather decided to go with that option). I think I might have an issue with the ignition module itself though because I can't get the test light to turn off no matter what position the rotor is in. I've checked all the wiring & it looks fine. I'll have to try checking all the individual components to see if there's an issue. I'll update as I make progress & once again thank you for all the input/suggestions thus far.

[LaceyDucati]

Looks the same as the Dyna S systems I've seen. Is there a mechanical advance mechanism behind the rotor? Installation/setting instructions are online for this system. You can connect a timing light between the blue wire and ground and use it as you would for a set of points. This assumes you have a charged 12v battery connected to the system. If the light is not going on and off when you turn the rotor, then the hall effect unit (trigger) is most likely dead, baring any wiring/kill switch faults. These hall effect units are effectively just a replacement for the points. The wiring looks to be touching the rotor, it should be looped around the inner diameter of the housing on its way to the trigger unit.

https://www.manualslib.com/manual/39652 ... tml#manual

Nigel

[Jordan]

Good guess, Nigel. It is a DynaS electronic Hall Effect ignition unit.

These were the first electronic ignitions I noticed that don't have a separate black box - nice and simple.
Just connect the module wires to 12V battery switched power, and ignition coil.
The 3rd conductor is the module body, which is earthed.

They produce a square wave output for the coil, just like a points ignition system.
That means that if advance / retard is wanted, it is used used in conjunction with a mechanical device with springs and bobweights.

An inductive sensor (pickup unit) makes a waveform like a sine wave, which because it changes with engine revs, can be used to advance and retard spark timing, so don't need a mechanical advancer.

I just mention all this in case someone's confused with the different systems, like I was.