Max had a stroke

[madmax-im]

Well yesterday I ran about 100 miles and rode thru a bad thunderstorm and got pummeled by rain and wind...after about 10 mins of this I found a spot under an overpass to get out of the rain...10 mins later sun came out and i continued home...bike ran fine...this a.m. I start him up and he idles down off the choke..ok warmed up and I head out for a run...about 8 miles down the road and he starts intermittently running rough...then I smell raw gas..then he runs right...for a mile then starts running badly...again I smell gas...turned around and limped home...bike ran rough and had no power...at home I do the water on the header pipes trick and lo and behold #s 2 and 3 headers are cool no sizzle...so without going into it yet I suspect its the coils...not firing 2 cyls and the raw unburned gas going thru the carbs is what I smell...dunno what I am gonna do...i'm not an electrical guru..so I will start by looking at the carbs.

[Ken Talbot]

Pick-up coil wires - an easy diagnosis and fix, even for an electrical non-guru! In your case, they might not be broken, but the insulation may be badly cracked near the bottom crimp holder. With a ride in heavy rain, a bit of water seeps its way in around the rubber grommet where the wires come out of the case. The water then shorts out the wire with the cracked insulation - same result as having a broken wire. Open up the case and carefully first for any signs of moisture.

BTDT...

[dbeardslee]

Ken's probably right, but I'll throw something else out there. Are you still running the stock ignition coils? Water can cause the high tension wires to short out as well. If you get it in a relatively dark place and start it, throw some water on the high tension wires and see if you see sparks arcing from the wires to the valve cover. You can also check the primary and secondary resistance on the coils with a DMM which may give you an indication. If that turns out to be the problem, it's not too tough to graft new wires into the old coils. On the later model coils you have to be careful with the wire that goes into the short tunnel, and it does require some minor soldering. I just did a set for another member. When he tested the secondary resistance we were getting readings of 90k ohms. Put the new wires on and the resistance dropped right down to the 15k ohms they're supposed to have. JAT

[trbig]

And Ken is another GURU who should know by now that XJ doesn't have the pickup coil problems the XS has. Our pickup coils are solid mounted and stationary. I guess you could have moisture under that left sidecover causing the spark to jump around in there like in an old distributer cap though.

Mr. Beardslee is probably correct though in that you still have some moisture somewhere either in your coils under the tank, wires, or plug caps. Run a fan on it for a couple hours and the problem will probably go away.... until it rains again.


Tod

[madmax-im]

OK easy first....trying the fan idea...if thats not it I'll check the coils...its so blasted hot in my garage that i can only stay out there 10 mins. at a time...thermometer says over 100* and the humidity factor is quite high too...Even though I have learned a few things here working on bikes is not my forte...I am having a motivational problem due to depression over my lack of gainful employment...bills,taxes..geez I cant keep up...

[foreda]

Heat

I know all about the heat.. and mosquitoes down here are baaaaaaaaad!!!! Humidity is reallllly baaaaaaad!!

[Axel]

Tci

I'm afraid that is exactly what my XJ did when the TCI was bad . Good luck on it not being this but ...Always good to have an extra .

Here's a cheap one (so far) . XJ TCI's are expensive !

http://cgi.ebay.com/ebaymotors/1982-...5#ht_884wt_938

[Ken Talbot]

And Ken is another GURU who should know by now that XJ doesn't have the pickup coil problems the XS has. Our pickup coils are solid mounted and stationary. I guess you could have moisture under that left sidecover causing the spark to jump around in there like in an old distributer cap though.

I must have some sort of mental block about that, TRBIG. This isn't the first time I've leaped to the pick-up coil wire answer for someone with a problem on an XJ. Good thing we've got folks here who own all of the various models.

BTW - I'm keeping my bet on cracked insulation!

[D. P. Larmee]

I have had similar issues on my standard after washing the bike or getting caught in the rain. On my bike, I believe that it had something to do with the connector that the pickup coil wires share with the neutral switch. Here is what happened to me. I have just washed the bike, it starts and idles perfectly. As soon as I kick it out of neutral into gear, it drops two cylinders. If I put it back into neutral, the dead cylinders come right back to life. After a few blocks of riding the heat from the engine has usually boiled off whatever water is causing the short and the the dead cylinders return.

[81xsproject]

For the umteenth time, the carbs are the LAST thing you should check in a troubleshooting process (especially if it was running just fine).

Now, obviously if you pull your bike out from under a tree and it's been there for 5 years, then yeah, the carbs are an immidiate check.

[madmax-im]

I'm afraid that is exactly what my XJ did when the TCI was bad . Good luck on it not being this but ...Always good to have an extra .

Here's a cheap one (so far) . XJ TCI's are expensive !

http://cgi.ebay.com/ebaymotors/1982-...5#ht_884wt_938

Thanks Alex...I have seen that guy'ads and he seems to have an attitude...so not sure I'd trust him...I have yet to determine what the exact cause is...I am fairly certain its electrical...I did have a fan blowing air on the electricals overnite but this a.m. it still was running on 2 cyls...so more than likely wet connections are not the issue...I looked quite carefully at all the wiring and no moisture was seen anywhere...

[dbeardslee]

Madmax - before you start buying parts do yourself a favor and run some tests with a digital multimeter. If you don't have one, they're not very expensive. Randy Rago's website has some good procedures for testing your TCI. As far as coils and such, pull your plug wires for the coil that runs to 2 & 3 (as that seems to be the affected coil) and put one probe on each high tension wire and take a reading. With resistor caps connected you should get a reading around 25k ohms. If it's way off, remove the plug caps and try it again - reading should be around 15k ohms. If it looks bad with the caps, and good without them replace the caps. If it looks bad both ways replace the wires to the coils. You can also check the caps by themselves - resistor caps should give you a 5k ohm reading. If both readings look good check your voltages and resistances at the TCI. On an XS, if you pull the four wire connector at the TCI and hold it so the 'slots' are horizontal put your probes on the 'top' connectors and 'bottom' connectors in pairs. Set you DMM to the 2k ohm range and take the readings. Should be 720 ohms plus or minus 20%. If it's outside that range look to your pickup coils for the problem. Again, this is for an XS. I don't know if it's the same for an XJ, but I'm sure Tod will let us know if I'm all wet on the range . You can check the voltages by pulling the big connector at the TCI. Place one probe on the orange wire, and the other grounded to the frame. With the ignition on you should get a reading of 12v. Repeat the procedure for the red/whit, grey, and wht/red - all should be 12v. Check the black/wht in the same way and you should get a reading of 6v (again, these are procedures for XS - Tod, are they the same on the XJ?). If the readings are off start looking at your electrical connections. And try not to sweat all over it while you're doing it - I feel for you on that humid 100 degree garage.

[madmax-im]

Madmax - before you start buying parts do yourself a favor and run some tests with a digital multimeter. If you don't have one, they're not very expensive. Randy Rago's website has some good procedures for testing your TCI. As far as coils and such, pull your plug wires for the coil that runs to 2 & 3 (as that seems to be the affected coil) and put one probe on each high tension wire and take a reading. With resistor caps connected you should get a reading around 25k ohms. If it's way off, remove the plug caps and try it again - reading should be around 15k ohms. If it looks bad with the caps, and good without them replace the caps. If it looks bad both ways replace the wires to the coils. You can also check the caps by themselves - resistor caps should give you a 5k ohm reading. If both readings look good check your voltages and resistances at the TCI. On an XS, if you pull the four wire connector at the TCI and hold it so the 'slots' are horizontal put your probes on the 'top' connectors and 'bottom' connectors in pairs. Set you DMM to the 2k ohm range and take the readings. Should be 720 ohms plus or minus 20%. If it's outside that range look to your pickup coils for the problem. Again, this is for an XS. I don't know if it's the same for an XJ, but I'm sure Tod will let us know if I'm all wet on the range . You can check the voltages by pulling the big connector at the TCI. Place one probe on the orange wire, and the other grounded to the frame. With the ignition on you should get a reading of 12v. Repeat the procedure for the red/whit, grey, and wht/red - all should be 12v. Check the black/wht in the same way and you should get a reading of 6v (again, these are procedures for XS - Tod, are they the same on the XJ?). If the readings are off start looking at your electrical connections. And try not to sweat all over it while you're doing it - I feel for you on that humid 100 degree garage.

Thanks for the advice...dont worry I can ill-afford to buy needless parts...

[trbig]

As far as coils and such, pull your plug wires for the coil that runs to 2 & 3 (as that seems to be the affected coil) and put one probe on each high tension wire and take a reading. With resistor caps connected you should get a reading around 25k ohms. If it's way off, remove the plug caps and try it again - reading should be around 15k ohms.

I'm definately not the go-to guy for electrical stuff, but I do know the stock XJ coils have the wires fairly permanently mounted inside the coils. I have looked at a set and tried to determine how to non-destructively remove and replace them... but I couldn't figure it out.

I have no clue as to the ohm or voltage values to what wires though...

Something I have seen though that I haven't been able to explain, is on the pickup coils, I've had a couple different sets where the timining plate has rubbed the pickup coil?? It would seem to me the crank would have to move to allow this?? But something to check. It didn't seem to hurt the coil, but it smeared that plastic over it a bit.

Something else to look at before you start buying.. lol.

Tod

[dbeardslee]

but I do know the stock XJ coils have the wires fairly permanently mounted inside the coils. I have looked at a set and tried to determine how to non-destructively remove and replace them

If they're anything like the '81 XS coils they can still be changed. The wire that goes into the short tunnel is soldered to a small copper lead that disappears into the coil body. You have to grind it down slowly with a dremel tool until you start hitting metal, and then carefully grind around the metal until you uncover the soldered connection. You can tell when you're getting close when you start hitting a white gummy substance (no comments from the peanut gallery ). At that point you can unsolder the connection, unwrap the copper lead from the wire core, and by twisting and pulling withdraw the wire. Then you strip the insulation off maybe 1/2" (sorry metric guys) of the new high tension wire, put a little wd-40 on the end of the wire and insert it in the tunnel. Solder the copper lead to the high tension wire core, RTV it, and after it has cured for 24 hours put a piece of duct tape over the repair and use a zip tie around the coil to secure the wire. I don't think there is a way to do it without doing a little destruction first.

Tod - On the XJ coils where the wires go in, is there a short tunnel and a long one, or just two short tunnels? Are the specs the same for the XS and XJ coils (3.3 ohm primary resistance, 15k ohm secondary, 15k volts output).

If they are I have a set out in the man cave I was going to redo that came off an '81 XS. I'd be willing to redo those and exchange them for Max's set if he's willing to spring for the wires - if the DMM shows them to be bad, and assuming the readings on the set I have are within spec when the deed is done.