Random stalling, trouble starting when warm

[jpdevol]

Were it me, I'd replace both coils with new and plug caps. If you're running resistor plugs, run non-resistor caps.
"Pamco Pete" recommended the following coils.
https://www.mikesxs.net/yamaha-xs65...n-coil-oem-30400-306-672-4m4-82310-60-00.html

https://www.mikesxs.net/yamaha-xs650-ultimate-high-output-coil.html

5Twins, Jim and others recommend a Honda MP08 type coil

https://www.xs650.com/threads/ignition-problems.60900/#post-719892

"Pick your poison"

Curious: why are you checking voltage while kicking? I've never tried that and I don't think you're gonna get anything accurate that way.

 

[peterg]

Thanks. I have a voltmeter on my bike. After each kick the voltmeter is showing random voltages. As if there is a draw when the motor is in one stroke but not in another stroke.

 

[peterg]

It is a single coil.

 

[Jan_P]

No experience on Pamco
Done a bit reading ..If the bike runs fine cold and stalls when warming up
on both sides I would look for electric problems .( As others here )

I had starting problems with stock coils .when they got warm but it did not stall.

Assuming wiring is serviced ..and ground is solid

I would suspect the pamco and start letting it idle to a stall and then take out the plugs immediately still warm and look at the sparks .grounded plugs
If weak or non existent I would try to cool down the Pamco electronic via air stream or so ...and then do it over again.
( Perhaps wet rags ?? )
On HiFi equipment one can use cooling spray..

Not saying it is the right forward here just potting it here as thinking out loud please do the read up

https://www.biltema.se/en-se/car-ca...ive-sealant-materials/freeze-spray-2000040315

Fluctuating Voltage on start up I don't believe is a problem unless low 11 ish or lower indicating a short somewhere.
A video could help .. Listening to if the timing is about right some light blipping
Since it starts cold I would assume it about right .. but if it starts misfiring heating up and die

Hot air gun can be an option reproducing heat and fault ....carefully
https://www.biltema.se/en-se/construction/paint/painting-tools/hot-air-guns/

And IR thermometer
https://www.biltema.se/en-se/tools/...-thermometers/infrared-thermometer-2000044496

on the coil as well

 

[5twins]

Yes, that 5.5 ohms on the primary does seem rather high. I see that coil is sold as a direct replacement for the stock TCI coil. Although no primary spec is given for that coil, the TCI normally uses something in the 2.5 to 3 ohm range. But let me ask you this - did you touch your tester leads together first and then subtract any reading you got from your coil measurement? You'll often get a couple ohms reading on just the leads and that can really throw off a low ohms reading like you're trying to take.

 

[peterg]

Thanks Jan. I will look at the Pamco and test as you suggest. I’m dreading having problems with it since it’s not an easy fix if broken.

5twins. I just tested the multimeter. The reading with the leads touching is 0.5 ohms. That means the primary reading is about 5 ohms - 0.5 ohms more than the Pamco spec.

 

[Jan_P]

lets see what happens

Thanks Jan. I will look at the Pamco and test as you suggest. I’m dreading having problems with it since it’s not an easy fix if broken.

As they say on television the Detectives -- this is an ongoing investigation .. half of the cases it is something simple like a loose connector
or a fuse .. kill switch , ignition lock ground loose .

I have not had any Carburetor problems to speak of for 40 years and definitely not one shutting down both sides
And very few wires off or damaged. no more than five.

Do you have fuel supply -- petcock opening -- and tank venting.

 

[peterg]

No problems with fuel.

I was planning on changing the coil, caps and plugs but am going to check for loose electrical connections first. Today I went for a 25k/16m city/suburb ride - took about 1 1/2 hours. Started cold first kick with the choke. First hour of the ride was ok. Then the voltage started jumping from under 11 to 14 and I felt the motor responding to the voltage. Got home, hit the kill switch and voltage read about 10.5. Turned off the key switch then back on. 13.2 volts. Electric start worked (after a few stater grindings). Turned it off. Tried 2 kicks with a bit of throttle. No go. Tried a third kick, no throttle and it started. I’ve probably been flooding the motor trying to restart after a stall.

I’ll find out how to check the reg/rec as well as checking connections.

 

[jpdevol]

Then the voltage started jumping from under 11 to 14 and I felt the motor responding to the voltage. Got home, hit the kill switch and voltage read about 10.5. Turned off the switch then back on. 13.2 volts. Electric start worked (after a few stater grindings). Turned it off.

Ok, there may be a clue there in that passage I copied: pondering. For anyone else following I've attached wiring diagram in question from OP other thread. (peterg please update if changed from shown)

 

[peterg]

Updated the line “turned off the switch then back on” to read “turned off the key switch then back on”

 

[peterg]

Thanks jpdevol. The kill/start switch is my prime suspect.

 

[jpdevol]

You can measure voltage in and voltage out to see if it (they) has excess resistance causing a voltage drop - more telling than straight ohm reading I think.

Frankly, I think it's further down the line: the coils or the e-advancer. The former is a little out of spec and cheaper to replace. Guessing, of course. Perhaps I'm just stuck on the excess draw theory.

Did you ever measure AC output at idle? Mike's does give specs. Also, seems I've heard the magnets in the rotor can be suspect.

 

[peterg]

Jpdevol. After testing the Pamco voltage I’m on side with your assessment. Not that I was ever disagreeing with it but I was hoping for a less costly issue and less riding down time! There is a sign of overheating on the e-advance chip - a bit of grey powder on the chip (ash?). The reading at the green wire from the e-advance to the sensor is somewhat constant at 2 volts. I understand it should range from 1 to 12 volts.

I’ll be joining the growing list of those on this forum who swap out their pamco ignitions. In my case to a Boyer unit.

I haven’t tested the AC yet but will need to do so when I get erratic DC readings. I might just replace the reg/rec for the sake of it.

 

[jpdevol]

An unfortunate result. Perhaps test the AC voltage to verify XS charge integrity. If it has issues too, knowing now will put you ahead of the game and opens-up opportunity to replace the whole system with a quality integrated charging/ignition system. Yes, costly: Ignition only ~$300, Integrated system ~$700.

XS Charge testing: https://www.mikesxs.net/blog/how-to-test-the-xs-charge-pma-system/

 

[peterg]

Thanks for the testing instructions. I don’t have a stator puller so I’ll test it on the bike.

A couple of questions:

I take it this is referring to dc voltage? If so I’m getting that range.

Sounds like I need to run the bike without the pma connected with only the battery providing charging power. Won’t this deplete the battery?

 

[Jan_P]

I do believe there is a stator inside the rotor the electric machine must have one otherwise no charging
Thanks for the testing instructions. I don’t have a stator so I’ll test it on the bike.

The battery is either receiving current ( Charging ) or use its stored energy ( Discharging )
Sounds like I need to run the bike without the pma connected with only the battery providing charging power. Won’t this deplete the battery?

Depending on battery size it can run a while on batter only

But please follow instructions running electrics and electronics without all parts connected can in some cases damage the components

 

[jpdevol]

Sorry peterg - I thought you had an XS Charge system??

Edit: well maybe you do have an XS Charge. You also have a stator, you can check it installed on bike, just unconnect the block connector and do the resistance checks. But first, leave it plugged in and test the AC output while running @idle with the multimeter probes @ the block connector.

 

[peterg]

Thanks Jan and jpdevol

I meant to say “I don’t have a stator puller so I’ll test it while it’s on the bike”. The instructions say to remove it from the bike.

I do have an xscharge pma. I will test the ac at the block connector. The mikes instructions are a bit unclear to me and I thought I had to test with the stator unplugged.

My checklist is:
-Warm up motor
-Test ac voltage at stator/reg connection block
-turn off power
-unplug stator/reg connection
-test stator continuity
-test reg/rec with diode setting on multimeter

 

[jpdevol]

Mike's specs the AC output "no load", so just turn headlight off (close enough IMO)