Carb Synch giving me fits

[BillyRok]

So you are saying that the voltage at the coils should be the same as at the battery and cleaning the contacts in the ignition switch may eliminate the drop I see now? thanks

[IanDMacDonald]

I believe Motoman said dirty contacts within the ignition is one of "many". Ideally, you'd want to see close to source voltage at the coils. Years of corrosion will definitely cause resistance, equaling voltage drop. Resistance measuring is no easy task (Ask Nate about his amnmeter install). Some cheat bypassing the entire harness by doingba coil relay mod. Others modify the harness ground locations to a songle ground. There are a lot of electrical tricks to perform. On my 750E, I completely re-did my harness with larger gauge wire, etc. It all comes down to money, energy, and time.

[skids]

So you are saying that the voltage at the coils should be the same as at the battery and cleaning the contacts in the ignition switch may eliminate the drop I see now? thanks

If there is any doubt, get one of those see-through spark indicators and hook it in to the plug/connector. I am going out on a limb to say that this doesn't have anything to do with your carb synch and mixture setting issues. You said that your idle was irratic and I think you problems would be dirrerent if you had too low of voltage to make spark. Maybe I am missing the point!

[IanDMacDonald]

I think there comes a point where you have to accept some things the way they are and go for the best tune you can with what you got. I have stock coils, stock fuse box, etc. A lot of my complaints with regard to running issues could very well be a direct result tied to both of those two components. Voltage drop on these bikes (everything this old exposed to elements of weather) is most common. Upgrading certain electrical things are mods that are a choice. I, have every intention of upgrading coils, fuse box, etc., to make sure my bike runs for another 30 years. I would not call it a production fault, I'd call it a miracle to see a 35 year-old bike still running, and still turning heads all these years later.

[motoman]

If there is any doubt, get one of those see-through spark indicators and hook it in to the plug/connector. I am going out on a limb to say that this doesn't have anything to do with your carb synch and mixture setting issues. You said that your idle was irratic and I think you problems would be dirrerent if you had too low of voltage to make spark. Maybe I am missing the point!

Opps.....that limb snapped.....

[motoman]

I think there comes a point where you have to accept some things the way they are and go for the best tune you can with what you got. I have stock coils, stock fuse box, etc. A lot of my complaints with regard to running issues could very well be a direct result tied to both of those two components. Voltage drop on these bikes (everything this old exposed to elements of weather) is most common. Upgrading certain electrical things are mods that are a choice. I, have every intention of upgrading coils, fuse box, etc., to make sure my bike runs for another 30 years. I would not call it a production fault, I'd call it a miracle to see a 35 year-old bike still running, and still turning heads all these years later.

Primary/secondary ignition maintenance and some upgrades is a necessity, not a choice, if intention is to be able to CORRECTLY tune the carbs. A weak spark can have you leaning the mixture so it WILL fire what would seem normal by the plugsthroughout the idle circuit rpm.......untill you take it for 50 mile cruise out on the slab at 4500-5000rpm and pull plugs seeing white like they come new out of the box, or worse, a grey lookin electrode. These motors with stock intake/exhaust by design are already runnin' a tad on the lean side. No need to agitate that more with failing coils/electrical connections, having to bring revs up for a higher charging rate to make up the difference. IMO, at that point, motor is wanting more fuel for the burn mixture with a hotter spark. Least that's what we had to do back in the day in the drag race performance cirlce, ****-canning your old stock ignition for a MSD6AL performance street ignition with some serious volts to the plugs. Then you could richen up the mixture so it wouldn't lean out on the other end of the 1320.......pretty basic stuff.

[BillyRok]

http://www.xs11.com/forum/showthread.php?t=39868
The ignition switch cleaning post is by DGXSER in the Repairs section under Battery & Electrical.

Additional info: I am running the stock coils (should upgrade them this winter), have new plug boots with proper resistance, snipped back the plug wire ends, and have a new battery. Using TC's fuse block, cleaned grounds/connections with Deox It and/or sand paper and applied dielectric grease. I have NOT cleaned the ignition switch yet, but will. After I tackled the turn signal switch and had little parts fly all over, I was gun shy about continuing but that switch is probably as gunked up as the others so I'll pay close attention to the tech tip and give it a go.

[natemoen]

After you take the ignition switch sort and clean it put some dielectric grease on the copper contacts before reassembly.

Then get yourself a can of lock lube that has graphite in it. Spray that down in the key slot and work the key around. Do not use a lube like wd40 or silicone or whatnot on the lock.

[BillyRok]

I took the ignition switch apart, my XJ switch is a little different than the one in the tech tip. Here's what I found...
[IMG][/IMG]

[IMG][/IMG]

The copper contacts didn't look that bad, but I did use DeoxIT and 600 grit paper to clean them up. With the key on, voltage at the battery is 12.20 and I have 10.70 and 10.80 at the coils.

How close are the readings at the battery vs. coils supposed to be? Where else might I be losing voltage?

[CaptonZap]

The power goes from the ignition switch through the ignition fuse, then the emergency kill switch to the ignition module and the coils on the red/white wires.
Is that where you are measuring the voltage?
Since you have honed your switch repair skills, apply them to the kill switch and see if that helps.
CZ

[BillyRok]

Hey CZ - Was taking measurements based on Motoman's post #27. Turned key on and used multimeter to measure voltage across the battery terminals. Then with key still on, stick pos lead into red/white wire at coil plug in with neg lead where 3 wires connect to rear of regulator/rectifier, check 2 times once for each coil connector. I'll take the kill switch apart and report back. Thanks