Even after installing Pamco, bike still stumbles at idle

it's just better to know 100% so it can be ruled out. i fought with my xj carbs for weeks till they where properly cleaned.

i even got them back from a shop and they weren't properly cleaned. there was a port in the float bowl that manages fuel on idle that was blocked in 2 of 4 carbs
 
Oh yeah, I did check that, the advance does snap back just like in the vid and I've also got the timing right, just took a slight adjustment so now I'm on to other possible sources. Thanks for the vid, that's what I used!

-j
 
Here's my motherly advice. Go to the thrift store and get a $5 crock pot. On the way home stop at O'Reilly's and get a gallon of Berryman's Chem Dip carb cleaner. Dismantle your carbs completely, leaving no rubber or plastic parts. Put them in the crock pot with the Chem Dip (one carb at a time unless you got the big crock pot for $7 like I told you) turn the heat on low and let them luxuriate in a soothing hot bath over night.

Take the parts out (one at a time and while they are still warm) and, wearing a face shield, blow them out good with your compressor. You will finally get that dang little piece of crud that's clogging your pilot jet or whatever.
 
I had a similar problem on one of my other bikes. I wasn't getting a full 12 volts at the coil. After 30 years the wiring and switches built up some resistenace becasue of corrosion. Check your voltage at the coil at idle. I did the coil repower mod after fighting a "carb" issue. Night and day difference. Every bike I've owned since has had this mod done and it makes a big difference everytime.
 
annOyed,

If you want to have the same advantage as the relay setup, but without the relay, just run your positive wire from the coil directly to battery through a 10 A fuse. Leave the red wire from the PAMCO connected to the red/white wire.

The coil will have power directly from the battery at all times, but no current will flow unless the PAMCO is working with battery from the kill switch and ignition switch red/white wire.

The PAMCO only draws 10ma, so that is all the current that will be going through the kill switch.

This is the way I have my '81/H hooked up.
 
What is your idle speed set to? If it is set to low it will stall occasionally. I set mine to 1200 rpm, The later models with the leaner carb settings may need 1500 rpm idle to keep from stalling.
Too low an idle speed will not charge as well and this can let the engine stall.
 
Yeah, I have to keep the idle closer to 2000 to prevent it from stalling and occasionally even at that idle it will quit. Hopefully this weekend I can try the coil repower mod.

-j
 
To need the idle set that high, I might suspect the carbs. If you havn't had them off to clean at least three times they are still a suspect. There are several tiny holes that need to be clean before it will idle right. It often takes a few or more times of cleaning before they get clean.
The three or four holes in the venturi by the throttle plate are very small. I use a wire tie from a loaf of bread. Strip the covering off one end. I use this thin wire to carefully probe these holes. It works to probe the pilot jet too.
 
Well, I did connect my coil directly to the battery with a fuse between the two, that went fine, but when I went out for a ride, same intermittent missing/threatening to stall at idle - I do like the concept and will leave it that way. So, since I'm no longer using it to run the bike, that rules out the charging system. Carbs next. Blah.

-j
 
Leo... on a note related to this thread and annoyed's issue:

What is your idle speed set to? If it is set to low it will stall occasionally. I set mine to 1200 rpm, The later models with the leaner carb settings may need 1500 rpm idle to keep from stalling.
Too low an idle speed will not charge as well and this can let the engine stall.
Click to expand...

Now that idle's hot, right? I have been trying to keep mine at around 1200, but at what point is your idle so high that you start to get into the ATU, essentially telling it that you're getting into off-idle and asking it to get ready for more fuel? I have heard that too high an idle can enact the ATU to start to advance and cause issues.

TC
 
To get the ATU to start working the engine speed will need to be somewhere around 2500 rpm.
I have the linked carbs on mine. I have a plastic valve stem cap squeezed on the idle speed screw. I try to keep the idle speed at 1200 hot or cold. With the valve cap on the idle speed screw it makes the adjustment easy, just your fingers, no screwdriver.
On your carb set up it will be a bit harder to adjust the idle speed that easy. You can put the valve caps on but keeping the adjustments even may be tricky. I used to use a small piece of thin steel placed between the idle speed screw and the stop. You can try that, you won't be readjusting the screws all the time that way.
With the two cable carbs I would set the idle to 1200 warmed up and just keep the rpms up with the throttle at start up until it will idle on it's own. Generally a minute or so.
 
Cleaned the carbs, put in the original pilot jet. Bike sounds odd, kind of a lower thumping sound to the ignition but rides. I think I better check the timing again.

-j
 
Well, because my coil is now running directly from the battery, so the charging system is merely a battery charger now. Don't know the voltage, ain't bought a multimeter yet... Ah, duh, yeah, if the charging system isn't working well, the battery voltage will not be what it should be right? What should it be? I've never used a multimeter, but I guess I'll get one this weekend and figure out how to use it. Can't believe this problem persists, its endless! To just be able to ride and not stall at the worst moments, like when the light turns green and there are several cars behind me; in NYC where the horns start BEFORE the light turns green!

-j
 
Last edited:
Battery voltage at idle it should be any where from 12 to 14 volts. When you rev it up it should climb to 14.5 volts and not go higher at any rpm.
A low charge can be caused by several things. Brushes, rotor, stator, reg/rec, wire connectors, grounds even a bad battery.
I would check the brushes, get the battery load tested, most any parts store can do it. Next is the rotor and stator ohms,
 
Cool thanks, I printed out Curly's charging system troubleshooting guide and will go get a multimeter. Just for the hell of it, I ordered some brushes and a regulator/rectifier, but I know how life works, neither of those will solve the problem; I'll install them and then follow the guide. I did try the feeler gauge test, and while the feeler gauge didn't "slap" the case, it did get pulled to it when I turned the key, so that was heartening.

-jonathan
 
After rigging the coil to run directly from the battery, cleaning the carbs twice, buying a multimeter, a new regulator/rectifier, brushes; after all of that, I still had the problem - at idle one cylinder was firing half the time. Finally I had the brilliant idea of swapping the plug wires and then the other cylinder did the same thing. Changed the plug wire, FIXED :doh:. HA HA HAHAAHAAAAA. Well, now I have all that new stuff on there so thats good anyway, though it appears my charging system was fine before I put all that stuff on anyway! I can ride while there is some summer left! Thanks to everyone who gave me advice and encouragement!

-jonathan
 
When I tested the suspect plug wire with the multimeter it tested fine. I think the problem was with the mounting of the big green coil. The rubber boot on the coil end of the wire was hard up against the top tube. Its possible that the tight fit and pressure was somehow causing a short. I don't know, but I shifted the coil so the wires come out unimpeded. This stalling/stumbling at idle problem has been with me since I got the bike a year ago, fully stock. I think replacing the ignition solved that problem but I never got to verify it because of this coil mounting/plug wire issue. I'm looking forward to a ride today to see how it runs.

-j
 

Similar threads

M
Idles poorly, surges and dies after 40 minutes of riding
Replies
5
Views
720
Halftwist
Halftwist
2ManyHobbies
77 xs650 won't start after mods
Replies
19
Views
564
sleddog83
sleddog83
HelmetTester
Hard start, stumble off idle and then idle dies
Replies
1
Views
707
HelmetTester
HelmetTester
JBMatthews82
Ignition trouble. Any guidance ?
Replies
19
Views
1K
Jan_P
J
Tlted_Jelli
83 xs650 Startup Frustrations: Advice Appreciated
2
Replies
33
Views
2K
Tlted_Jelli
Tlted_Jelli
Back
Top