Not Really Sure...

Captmandel

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Ok so i let my 72 xs sit for like 2 years because i assumed i had some big electrical issue. Fast forward to two days ago, i replaced the spark plugs, filled the tank, and off we go. So of course i started tinkering and now it doesn't seem to wanna start again. I realized my plugs kept fouling so that's where i started. I then learned that what i thought was the mixture screw was actually a sealed vacuum port(?) I found the mix screws and they were WAY rich. I believe after checking the plugs and gapping them to .030 that i have fixed the problem with them fouling. Then i adjusted the cam chain tensioner which was slightly in, now its perfectly flush as the manual suggests. I don't have the right tool to do the valves but 6 years ago or so i had the head gasket replaced and a "red neck" valve job done, as the mechanic put it. Still no start. I realized that while idling the bike i ate up the useable fuel. So, i cleaned the petcocks, and filled the tank about 1/4 of the way and it STARTED!! Then i rode around my neighborhood for about 3 mins and it died :( I tried kicking it back to life and nothing i also tried to push start it down the hill to no luck. As i was writing this i went back outside to check the fuel hoses and gas is def flowing. I tried to kick her over and she started first kick. Then died on the way outside of the garage. Then kicked over again and died again in the drive way. After that she wouldnt kick over at all. Im running a pamco ignition with a "banshee swap" pma. Any advice would be greatly appreciated. I'd love to take her to a mechanic at this point but 1. im a little afraid they are gonna tell me to throw it in a lake and 2. No one around me works on 50 year old bikes. Thanks for reading this, sorry for long post.
 
If we are talking a 3 min ride running properly . No bangs no stumbling .. on both cylinders and then immediately dying at the same time on both sides
I would look into the electrical side. Ignition and wiring
And I have no experience on neither Pamco nor pma So someone else is better on that.
If no one comes in we can do it.
 
Thanks for the reply. I def got some inconsistency in the right side exhaust sound but i think thats carb tuning which i cant do until i get the valves set. i went outside and it kicked up again, then died again once i took it up the block. Maybe has something to do with the clutch? Seems like it only dies when in gear. Seems like if it sits for 15 mins or so it starts up no problem but like i said dies again when i start riding. I have a shop to take it to now but not if i cant get it there :(
 
Could it be a stuck clutch plate? I mean i can shift through the gears and ride a bit before it dies. I saw a post about that but they all seem to die as soon as they are put in first.
 
Sounds like gummed up float needles and seats. Its getting some gas but not enough and the bowls are refilling slowly. Also be aware that these bike have to have a full 12VDC< at the battery.
 
Check to see if the breather hole in the gas cap is open! Sounds like fuel starvation. Open the gas cap and try it. Or what Rusty said.
 
"You might also want to check your coil. Just in case. When coils go belly up they have a tendency to run for 10 minutes, get hot, then stop working. Then it takes a couple minutes to cool before it starts. Then it'll do it again.
In my experience the bike wouldn't go 10-15 minutes if the vacuum was bad. One reason I use clear fuel lines, so I can see it flowing."

saw this in another thread, im wondering if its the coils? That would be an easy fix. Anyone know how to test the coil? Im running the high output coil from mikes xs i think.... been like 8 years since i installed them.
 
Testing the coil:

1. Using the lowest scale on the meter, measure the resistance between the primary terminals with the wires removed. Should read from 2.5 to 4.5 Ohms.
2. Using the highest scale on the meter, measure between one of the primary terminals and the center core of the coil. Should be infinite resistance. (open)
3. Measure between one of the primary terminals and one of the plug wire terminals. Should be infinite resistance. (open circuit)
4. Measure between one of the plug wire terminals and the core of the coil. Should be infinite resistance (open circuit)
5. Measure from one plug terminal to the other. Should be 15,000 to 20,000 Ohms


guess ill try this too
 
You have a timing light? If so, when it quits there at home, Open the seat and hook up the light. Connect around either plug wire. Tape the trigger if you have to and watch it as you kick it. If bike won't start and it looks like your getting good steady hits, it's probably not the coils.
 
We all been there, done that, at one time or another. Some like me are still doing it. Habit, I guess! :)

If the bike ran decent when it would run, it's probably not the timing either.
 
im using a capacitor so im not sure i can acheive the full 12 volts.

Update, it dies even at idle. However, i checked the carb drain on both sides and they dumped fuel out.
I would hook a battery up, at least until you know it runs properly. Trying to troubleshoot with a capacitor is kinda like shooting yourself in both feet at the same time. How much fuel dumped out, fuel in the float bowl does not always mean enough fuel in the float bowl. If the bike sat for a long time you could have plugged up carbs, and running it only served to knock loose a bunch of crud from the float bowls only to then lodge it in the jets.
 
Don't forget to check the valves. If they're too tight, that could be why it dies after a few minutes and after it heats up.
 
Stripping the carbs and cleaning them would be worth the effort anyway.
As the others say it’s probably electrical but sorting out reliable fuel supply is just good maintenance to eliminate a possible issue.

My bike ran badly and died when returning to idle.
My suspicion was electrical (loom is terrible); but a carb rebuild and new inlet rubbers cured it.
 
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