Bike Died While Riding, Now No Start

[Ricksonc]

I have a '78 XS650 Bobber that i built. PMA, Pamco, Capacitor, single kill (Toggle) switch)

I rode the bike on and off for about 3 hours on Saturday and about 2 min from home it died and wouldnt start up again.

I have it home and started testing all the connections as it seemed like it just lost power. All connections seem seem good (I have unplugged and plugged in everything).

While testing the coil power is disconnected from coil, I bought a cheap multi meter, I get ~4.7ohm between the two terminals, nothing between either terminal and the spark plug cap...not sure if that is the proper way of testing or if I just have a shitty multimeter? ( say this because I did the same test on my running xs650 and get the same results.

I tested the kill/toggle switch and that functions correctly, open when off and 1.0ohms when in the on position.

How do I test my Pamco?

How do I test my Regulator/Rectifier?

How do I test my PMA?

How do I test my Capacitor?

I have learned so much from this site and hope I can get this resolved. I know there is a lot out there on this topic but I have not been able to get a clear picture of how to test these that I understood. All help is appreciated.

 

[xjwmx]

I get ~4.7ohm between the two terminals, nothing between either terminal and the spark plug cap.

What do you get from plug cap to plug cap?

 

[Ricksonc]

I just connected a battery inline to power (coil and red from Pamco) and ground. No change.

 

[Ricksonc]

xjwmx,

With power connected to coil of no?

Just tested, either way no reading when meter set at the 200ohms setting.

 

[xjwmx]

^Ohms, no power. Could be a bad plug cap, wire pulled out of coil, or fried coil secondary. If it doesn't read open cap to cap it's probably okay.

 

[xjwmx]

Just tested, either way no reading when meter set at the 200ohms setting.

In that case pull the wires out of the coil and see if you get any reading. If still not, fried coil... If get reading then, then it's most likely a bad plug cap.

 

[Ricksonc]

Wires seem fine as per pictures Im getting a reading (just had the meter set wrong)
The plug cables do not come off my coil so I can not test directly at the coil.
Good reading between terminals (no power connected)
No reading between one terminal and one plug wire...BAD?

 

[Ricksonc]

This may sound like a dumb question but this is my first build does the coil need to be grounded. I have mine mounted on the rear motor mount tucked under the carbs. But I am not using the mounting points on the coil just a wrap around mount I had laying around.

 

[xjwmx]

The readings look okay. I thought you said you read nothing plug cap to plug cap.

Coil itself doesn't need to be grounded. One side of the primary probably goes to ground but that's taken care of in your wiring. I don't know anything about Pamcos, PMAs, and Capacitors instead of battery. My best advice is use the meter and be methodical.

 

[Ricksonc]

Okay, thanks. I will keep hunting then.

 

[mrtwowheel]

My understanding of how a coil mounts and works is that the coil is mounted to metal brackets that work as a heat sink to absorb and spread heat away from the coil.

Scott

 

[xjwmx]

^Actually the coil I'm using is rubber mounted in its natural habitat (Goldwing).

 

[Ricksonc]

Replaced the coil and Pamco today. No change! WTF

I have a replacement Reg/Rec I'll try next. If it's not that I'll replace the Capacitor.

Still open to ideas?

 

[xjwmx]

Yes. That is the most expensive and time consuming method of repair. That's why I suggested use the meter earlier -- find out how each part works or what it needs to do (you don't have to know the physics) and use the meter to see if there is something wrong with that part. The coil for example -- it needs to read some amount across the secondary, some much smaller amount across the primary, and open between the primary and secondary. It it does that it's not broken and you move on to the next part...until you've discovered what the problem is. But at least now it's kind of safe to say the coil and the Pamco are okay.

At this point you suspect the reg/rec, so use your meter to see if it's broken instead of just replacing it. You might replace everything on the bike but the problem is just a bad crimp on a connector... Find out where you should have 12 volts and use the meter to find the first place you don't have it. Use the meter to see if everything that's supposed to be grounded has continuity to the frame.

 

[650Skull]

Post #2 in this link for testing a Solid State Reg/Rect..http://www.xs650.com/threads/testing-a-rectifier.3272/#post-34317

Pamco ignition........http://www.xs650.com/threads/pamco-ignition.46859/

 

[Ricksonc]

^ thanks

I put my spare(new) Reg/Rec in and still no change.

I know it sounds expensive to throw new parts at the bike but I have a second XS650 that I bought all this for already, just sitting waiting to get to it when this one is fixed. So anything I test and doesn't fix will just go back to the other XS.

So all that's left to check is the Capacitor. How should I test that? I don't have one of those sitting here.

If that's good then I will be pulling the entire harness and rewriting to be sure at every connection.

 

[xjwmx]

The way to test a capacitor is use the C setting on your meter If it doesn't have that feature, with a big capacitor use the ohms setting and the ohms should start out low and move quickly to high. That's one thing that's easiest with a analog (needle) meter. Does the bike you're working on use the same parts, e.g. capacitor, pma, etc. as the parts bike? Put a resistor across the capacitor for a second to discharge it before you put the meter on it.

 

[Ricksonc]

The other XS is a cafe build in progress with all stock electronics currently. Plans are to do the same set up in it when I work this one out.

 

[Ricksonc]

Bump

 

[TwoManyXS1Bs]

This thread reminds me of another from long ago. Folks offered a variety of tests and solutions, poor fellow faithfully tried everything. Exhausted and exasperated, he finally checked his tank.

No gas.

Sometimes it can be the simplest things...