Transistor Ignitor Diagnostics - Failed?

[JonnyC]

Bike starts, but is really rough, and seems to lose different cylinders at different times. Did a full carb rebuild, so I suspected it was them since I see that there is spark. Had them off 3 times now to go through them, and each time I put them on a different cylinder is now acting up. Originally #2 exhaust header was cold, then it was #1, then #3. I can pull spark plug wires and not have it affect the idle.

Decided to test the ignitor (bought the bike years ago in a non-running state - bad idea). This is an '83 650G, so it has the transistorized ignitor. With ignition on, connecting an ohmmeter under any setting (don't have a 1xOhm setting) to the signal generator input leads on the ignitor will not cause a spark. Read that I could use a 1.5v battery. When connected one way, plug #1 will spark. Remove battery, nothing. Flip battery around, connect it, and #2 will spark. Nothing when it's removed.

Is this the way it should function? Or is my ignitor bad?

One other observation is that at times the ignitor got really hot to the touch while the bike was running. Other times it wasn't nearly as warm.

Also, I can't swap it out for a Dyna S, correct? The Dyna only works on mechanical advance systems?

[posplayr]

Don't try to invent a new test method unless you are trying to learn electronics instead of fix your bike.
There is an ignitor test in the FACTORY manual.

Short of that a timing light, RPM meter or a scope is helpful to see missed sparks(intermittence).


The ignitor getting real hot is not a good sign.

[JonnyC]

Well I'm not inventing anything, just going off of the vast knowledge from members on this site. I don't have a 1xOhm setting on my DVOM (as explained in the factory manual), so I had to try to find another way to test it (I believe the battery method came from Matchless).

Actually, thanks for the reminder. I have a pocket oscilloscope that I can hook up to the coil output wires from the ignitor and see what's going on. Hell, I can record in slow motion on my phone one of the plugs grounded to the block and see if it's missing any.

[posplayr]

Well I'm not inventing anything, just going off of the vast knowledge from members on this site. I don't have a 1xOhm setting on my DVOM (as explained in the factory manual), so I had to try to find another way to test it (I believe the battery method came from Matchless).

Actually, thanks for the reminder. I have a pocket oscilloscope that I can hook up to the coil output wires from the ignitor and see what's going on. Hell, I can record in slow motion on my phone one of the plugs grounded to the block and see if it's missing any.

Sorry, I see that the ohmmeter with 1xOhm is a described tests with described criteria. Unfortunately you don't have the required equipment so it should be no surprised the test does not work.

I have never seen Matchless description of a test using a 1.5V battery but assume he would have also described what you should see. You deviate and you're on you own(unless it is something interesting ).

My suggestion is to do an integrated test which only requires a volt meter. Plug the pickup into the ignitor and crank over the motor. The output of the ignitor should go from +12V to ground and the plug should spark at that moment. If that doesn't work something is busted and it won't fire.

[tom203]

" and each time I put them on a different cylinder is now acting up. "

This doesn't sound like an ignitor problem, probably misconnected plug wires or carb problem. With ignition "on" ignitor has about 3 amps running thru it thanks to draw of one ignition coil, so it feels warm
All the 650 shafties had mechsnical advance, so the dyna is an option.

[JonnyC]

All the 650 shafties had mechsnical advance, so the dyna is an option.

Ah yeah, I read this part, "Ignition timing is maintained properly at all times and require no maintenance" and thought that the advance mechanism was built into the ignitor. I then read the signal generator "is comprised of an iron rotor attached to a mechanical advance mechanism". Popped the signal generator cover off, and what do you know, it has a mechanical advance. I'll throw a timing light on it now and see what's going on.

What the hell does the ignitor all do then? Seems like it would be a pretty simple circuit.

Why does the 650 always get "shafted" (ha, get it?)? Dyna doesn't list anything for the 650, but since I see ND stamps on the signal generator and the ignitor, I would think the DS3-2 would work?

[JonnyC]

Screw it, I just ordered the Dyna DS3-2. This entire bike will be brand new by the time I'm done with it.

[tom203]

That will work: not listed for the 650 because the dyna plate needs slight modification to clear oil sending unit as you will find out!

[JonnyC]

That will work: not listed for the 650 because the dyna plate needs slight modification to clear oil sending unit as you will find out!

Thanks for the heads up!

[JonnyC]

Hey Tom,

Is there a thread on here which discusses modifying the dyna plate to fit the 650? The problem looks to be that the metal I have to cut away would remove the mounting location for the wiring support. This is going to sound stupid, but could I relocate the oil sensor to the inspection plug on the filter housing to free up some room?

EDIT: Well nevermind, it looks like it will just barely fit...



- Jon

[tom203]

"EDIT: Well nevermind, it looks like it will just barely fit..."

Many have done it successfully, but dyna was worried about others being hamfisted during install!

[JonnyC]

Got the Dyna S in. I cut out a half moon for the oil pressure sensor, then had to flip the wire strain relief upside down as it was hitting the oil sensor. After this picture was taken I clocked everything (had to be rotated to the right quite a bit) to the advanced mark with rotor fully advanced so it's ready to fire up once I get a crimper to finish up my wiring. Finally I'll be able to use my timing light for maybe the 3rd time in 10 years. Also note I'm missing a screw because it was pretty mangled - someone was already in there I think to replace the oil seal. Going to the hardware store to get 3 new ones tomorrow.



Thanks again for the heads up Tom.

Side note, I really need to make a conscious effort to be more organized. Not much of a workbench when there's no room on it.

[Lorenzo]

Not much of a workbench when there's no room on it.

It's kinda groovy though...