PMA/PAMCO - Sponanteous Bog with throttle - Idles fine

[Tyler Jay]

BIKE:
79 XS PMA/PAMCO/Sparx Capacitor/Kick-only/Lighting system on separate toggle circuit

BACKSTORY:
My daily bike, I was riding around all day, turned it off, then all of a sudden hard to kick over, once I did, it bogged with any throttle applied.

TESTS: (Fires and idles fine at low rpm with all tests)
Cleaned Carbs - Checked all functions. Butterflys, Vacuum Diaphragms, Ports, holes and orifices. Twice.
Swapped Carbs/Intake Manifolds for VM36s
Swapped Headers
Swapped Spark Plugs
Swapped Ignition Coils
Cleaned Grounds
Checked Diode of regulator/rec - all within 10% across 6
Checked Ohms of stator - all within 10%
Swapped capacitor for full charged battery 13.6v
Checked voltage at idle on battery - 13.8v ("battery tender" lithium battery 13.8v was max charge with mid rpm on a stock charging system) - drops to 13.4 with lighting circuit on.
I tried hooking a battery up, starting bike, and pulling the connection between stator and reg/rec. Results: turns off. But I'm not sure what that tells me. I'm electrically inept. Im stuck.

 

[I am Carbon]

Hi TJ
I would check timing to see if has retarded.
I would check ATU it might be stuck closed
I would also check fuel filter

 

[Tyler Jay]

I'll check the timing today.
For the ATU, I just need to ensure they spring back n forth correct?
Replaced fuel filter.

 

[pamcopete]

TylerJay,

Here is a video of the proper "snap back" operation of a mechanical advancer.

 

[Tyler Jay]

Hey Pete, mine doesnt snap back quite as well as yours when pulling on the arms. However it snaps when I turn the rotor.

 

[Tyler Jay]

Checked the timing, it's on mark.

 

[Tyler Jay]

I just realized the coils I tried swapping for we stock ones, not dual output.
Could coils cause such an issue? They read 2.9ohms on wiring leads 23,400ohms between caps.
If not coils, would I just have to put new springs on the advancer to get better "snap-back"? Or Pete's E-Advancer

 

[I am Carbon]

quote "I tried hooking a battery up, starting bike, and pulling the connection between stator and reg/rec. Results: turns off. But I'm not sure what that tells me. I'm electrically inept. Im stuck."
Please elaborate.
Hooked battery up to what Or where?

 

[Tyler Jay]

I am Carbon,
I hooked a battery up in place of the Sparx Capacitor. Connected the two positive leads from capacitor with a clipped wire and ran it to the battery as well as Ground lead to battery.

 

[I am Carbon]

well just pulling the connection between stator and reg/rec. shouldn't make the bike quit running with a good battery hooked up correctly. there's a stator test that can be preformed with that disconnected while engine is running on the battery. I'm only so so with the electrical so not sure how much help I can be.
a good battery connected to the ignition completely separate from charging system would be better at this point, then go for a start to see what happens.
Maybe someone with more electrical experience will chime in too.

 

[retiredgentleman]

"BACKSTORY:
My daily bike, I was riding around all day, turned it off, then all of a sudden hard to kick over, once I did, it bogged with any throttle applied."

It may be that the engine or its accessories such as the PMA are now binding/rubbing. Try taking out both spark plugs, and then turn the engine by hand. Engine should be easy to rotate. Listen for any strange sounds.

How long has the PMA been on the bike? Might be wise to take off the left engine cover and have a look around for any thing that looks abnormal.

 

[Tyler Jay]

Retiredgentleman,
I purchased the bike with the PMA 5 months ago. I believe the previous owner put it on but never rode it as the carbs were terribly out of sync when I got it.
Now that you mention it, I thought I heard a winding down noise at one point. I suppose I'll need a puller to get the rotor off to check it out.

 

[I am Carbon]

If you have the banshee PMA HERE is one $13.24 shipped

 

[Tyler Jay]

It looks like I have the PMA from mikesxs. I'm hoping I can get it off with a puller from advance auto or harbor freight. Its 80 deg out, I wanna ride!

 

[Tyler Jay]

I pulled the flywheel/rotor off and everything checked out, no signs of rubbing.
I'm getting a .9ohm reading between wire terminals. The charge on my capacitor at idle bounces from 13.6-13.8.
I'm so lost.

One other symptom, I'm getting a hanging/hovering idle when I twist throttle and when I get voltage on capacitor it drops to 11-12v.

I suppose next I'll try and borrow an ATU/advancer and swap it out.
Might as well do cam chain, valves, timing, and sync carbs for the hell of it.

 

[I am Carbon]

well have you connected a good battery to the ignition completely separate from charging system yet? And go for a start to see what happens?

 

[Tyler Jay]

Yeah, it died, unless I should disconnect it from the reg/rec instead if between stator-reg?

 

[I am Carbon]

I suggest that you connect the PAMCO to a separate battery sitting on the floor and not connected to the bikes charging system at all.
If it dies then it has nothing to do with charging system
What we are tryin to do is find out what isnt the problem

 

[I am Carbon]

if you can video your progress that can and quite often helps us help you.
I've needed help more than once and people seeing my videos have saved my azz from screwing up.

 

[Tyler Jay]

I'll have to get the girl to help me record. I tried the battery test again, however this time I disconnected the the ground from the reg/rec and it still dies. Before I pulled the wire I was watching the voltage on the battery and it didn't look as if it was charging, stayed at 13.6. Around in circles I go.