Runs absolutely perfect then wont start

[sickofitall]

Twice it's left me with no spark. Pma, cap, kickstart. I ride it here, I ride it over there, then back to here, then I go there and no spark. I truck it home. Takes a few days to get back to it. I put a spark tool on it that's inline from the plug to the head and still nothing. Put a battery in place of the cap and boom, starts right up. Runs between 13.5 and 14.5 solid. Battery takes a charge. Put the cap back on (new or old) boom starts right up. Checked all my wiring. No shorts. Idles nice. Runs great while I ride it and I mean perfect. Then all of a sudden it just won't start. No switch for head or tail. When it fires lights are bright right from the kick. When it won't fire headlight is dim almost nothing. I figure it's the cap or my coils but I figure if it's my coils they wouldn't stay dead for days. Or at least until I put a battery to them. And now that I wrote it out I'm thinking coils because the cap probably just doesn't have enough juice off the pma to charge them but a nice hot battery does.
I asked Hugh about it yesterday but I figure a few more opinions couldn't hurt. I have read every post on caps and ignition coils so please don't tell me to search.

 

[figure8]

The one problem that stands out is the headlight, it's commonly supposed to be off when starting with a cap then switched on once it's running....

 

[sickofitall]

I hear that. I've been riding this bike 2 years with no problems. I recently upgraded to a higher wattage lamp. So I have about a month with the new lamp and it wasn't a problem till about 2 weeks ago.

 

[kevski]

Possibly a loose connection in the PMA giving intermittent charging of battery, some of the Chinese ones have this problem.

 

[figure8]

I hear that. I've been riding this bike 2 years with no problems. I recently upgraded to a higher wattage lamp. So I have about a month with the new lamp and it wasn't a problem till about 2 weeks ago.

Adding a switch and seeing what happens would be pretty easy to do.

 

[sickofitall]

I don't think so. It'll push a constant charge to the battery for 10 min after I get it to fire off the battery. Steady 13.5-14.5 no problem. Here's my mental issue - I ride it and it runs perfect. No breakup, idles great, power all over. I can start it and stop it a few times then all of a sudden nothing. Coils will sometimes refire after they cool. This thing sat for 2 days before I tried to kick it again. At that point I got nothing. Then I hook up a 750cca battery in place of the cap and it fires first kick no choke. I remove the battery put the cap back in line and it fires. Over and over. I let it idle for 20 minutes (with a fan on it) lightly revving revving it and holding the throttle a lil here and there. Shut it down and it fires right back up.

 

[sickofitall]

I do have a switch and will try that but this thing has been tits, no problems for a long time now. Even after the new lamp install. Started evertime. 2 kicks to the cap and 1 to start.

 

[sickofitall]

I don't think so. It'll push a constant charge to the battery for 10 min after I get it to fire off the battery. Steady 13.5-14.5 no problem. Here's my mental issue - I ride it and it runs perfect. No breakup, idles great, power all over. I can start it and stop it a few times then all of a sudden nothing. Coils will sometimes refire after they cool. This thing sat for 2 days before I tried to kick it again. At that point I got nothing. Then I hook up a 750cca battery in place of the cap and it fires first kick no choke. I remove the battery put the cap back in line and it fires. Over and over. I let it idle for 20 minutes (with a fan on it) lightly revving revving it and holding the throttle a lil here and there. Shut it down and it fires right back up.

 

[NONclow]

My best guess.....your cap is not rated for the draw and is overheating.

Get a bigger cap, or swap the HL bulb for the weaker one and try it.

 

[sickofitall]

I want to think it's the cap as well. My thing is it won't spark for days till I eliminate the cap and go to battery. Then I'm right back to normal. I've even tried to start it with the headlight disconnected before I hook it to the battery. It's a sparks cap which I know is a low volt cap. I have a spare that I installed yesterday but didn't get a chance to take it out for a ride.

 

[figure8]

I want to think it's the cap as well. My thing is it won't spark for days till I eliminate the cap and go to battery. Then I'm right back to normal. I've even tried to start it with the headlight disconnected before I hook it to the battery. It's a sparks cap which I know is a low volt cap. I have a spare that I installed yesterday but didn't get a chance to take it out for a ride.

Since you have two, try running them in unison and see what happens.

 

[sickofitall]

Duh.... I should have thought of that.
I really appreciate the input brother.
That'll be my next step.
I can't eliminate a coil problem yet though other than maybe a big battery has enough juice to clear up a coil problem then it doesnt rear it's head until it gets warm.
It's hard for me to believe they would fire so well until I turn it off and then have nothing for days until a battery is used. Then back to normal. That's what I can't get my head around.

 

[figure8]

Let us know what happens, been a lot of these problems lately. Got me thinking I'll be making the switch to this or adding this in with a cap...

 

[sickofitall]

I will.
I'm thinking about just going with a mini lith battery as well.

 

[BlueNorth]

I hear that. I've been riding this bike 2 years with no problems. I recently upgraded to a higher wattage lamp. So I have about a month with the new lamp and it wasn't a problem till about 2 weeks ago.

A higher wattage headlight would draw more current and heat up the wires more.
If the problem started when you changed the headlight, perhaps you have a short somewhere due to melted wire insulation.

Just a thought

 

[BlueNorth]

It sounds like the headlight is drawing too much current for your charging system. Have you tried changing the headlight back to the stock wattage?

 

[sickofitall]

I went from 35 watts to 55 watts and it's bright. I checked all my wiring but I'll check it again. I can almost bet when I get home tonight it will start off the cap. Once it fails it won't start even with the lamp disconnected.

 

[sickofitall]

My headlight mount did break and the lamp flew by my head 4 weeks ago. But the glass didn't break and it still worked so I'm running it...

 

[BlueNorth]

Watts is Volts x Amps.

A 35 watt lamp draws 2.91 amps. The new 55 watt lamp draws 4.58 amps.

I seem to recall reading somewhere that the XS650 alternator only puts out 3.5 amps.

It's just a hunch but it sounds almost like your capacitor isn't fully charging due to the headlamp load.

 

[sickofitall]

It's running right now. 2 kicks to charge 1 kick to fire. Headlamp and tail on.
So what's the difference when it's hot.