Dead cylinders XS11

[dlbryant1]

I have a 78 XS11 witch I inherited about 6 month ago. When I first got this bike and filled it with fuel it poured from the carbs. New needle and seat time. I rode several weeks after the rebuild about 500 miles, this bike for an old timer ran great. I did note a slight miss after the 3rd week and a small backfire when first started. A couple days ago while riding I had a loss of power and barely made it home. The next day when I tried starting it only ran on 2 cylinders. I pulled the plugs and they were wet. I replace all 4 plugs and the bike ran great. I took off for a ride, made it about 15 miles and lost a couple cylinders. Back home I go to check, sure enough 2&3 dead. Changed plugs again run great. Made it about 2 miles and 1& 4 stop firing. I have checked pick-up coils @ 718 ohms, Primary @ 1.6 ohms, secondary @ 22,000 ohms. I think I have a coil or resistive cap going bad. Please any other suggestion. I don’t mind spending $125 for coil kit if I was sure this would fix my problem.

[sixtysix]

It's probably the pick up coil wires, as the advance unit moves these wire flex and come apart over time, just pull on them with your fingers and the break will become appearant.

See this thread for instructions:

http://www.xs11.com/forum/showthread.php?threadid=543

[strom]

Hmmm... also check for XSive smoking... if it's burning oil, your valve seals might have followed mine.

LP

[dlbryant1]

No blue smoke just a little black if you rev it quick. Checked pick up coil wires and the vacuum advance, everything is ok there. The spark does not look strong so I orderd a spark gap checker to test spark. I never lost all fire. I would lose cylinders while riding at 55 mph, sometimes when I stopped and let it idle the cylinders would start to fire and I could take off again. I tried the tank vent thing and also checked to see if there was fuel in the float bowls. This problem is slowly getting worse and I hope something goes bad so I can say here it is. All I have to do is put new plugs in and it run fine for a little while.

[skids]

Re: Dead cylinders XS11

I am thinking that the pick-up coils are not the issue here becase the problem is switching to different cylinder pairs. If your battery is questionable, remember that the ignition module starts giving up at around 10.5 volts. No spark can lead to wet plugs for the set that isn't firing. Weak batteries can seem OK with a volt meter because of a "skin charge" but have no real capacity for any period of time. Also, check your air filter to make sure it isn't loaded and make sure you aren't sitting on your snorkle (airbox intake).

Originally posted by dlbryant1


I have a 78 XS11 witch I inherited about 6 month ago.

[strom]

OK, I'd suggest a new coil wires, plug caps and plugs. I would also check your generator/regulator.

LP

[dlbryant1]

I went back a rechecked the coils and Caps, this is what I found.

Coil #1 & 4 15.4K ohms
Coil #2 & 3 15.8K ohms

Spark Plug cap #1 8.9K ohms
Spark Plug cap #2 4.8K ohms
Spark Plug cap #3 4.8K ohms
Spark Plug cap #4 8.8K ohms

Where & What kind of spark plug cap should I use to replace the old one? 5K Resistive or non resistive? If I use non resistive do I have to use a resistive plug. Does anyone have part #'s?

[sixtysix]

Originally posted by dlbryant1
I went back a rechecked the coils and Caps, this is what I found.

Coil #1 & 4 15.4K ohms
Coil #2 & 3 15.8K ohms

Spark Plug cap #1 8.9K ohms
Spark Plug cap #2 4.8K ohms
Spark Plug cap #3 4.8K ohms
Spark Plug cap #4 8.8K ohms

Where & What kind of spark plug cap should I use to replace the old one? 5K Resistive or non resistive? If I use non resistive do I have to use a resistive plug. Does anyone have part #'s?

Yes this thread has the part numbers:
http://www.xs11.com/forum/showthread...&threadid=1882

[Geezer]

Originally posted by dlbryant1
I went back a rechecked the coils and Caps, this is what I found.

Coil #1 & 4 15.4K ohms
Coil #2 & 3 15.8K ohms

Spark Plug cap #1 8.9K ohms
Spark Plug cap #2 4.8K ohms
Spark Plug cap #3 4.8K ohms
Spark Plug cap #4 8.8K ohms

Where & What kind of spark plug cap should I use to replace the old one? 5K Resistive or non resistive? If I use non resistive do I have to use a resistive plug. Does anyone have part #'s?

I once saw the same problem on a RD350. It was almost new at the time and the mechanic that owned it was going crazy until he check the plug caps. Anyway I prefer the non-resistor type plug caps. Any good bike shop should have them in stock.

Geezer

[dlbryant1]

Thanks for the help and all the good info. I will order a set a let everybody know if this fixes my problem.

Thanks again!!!

[skids]

I suppose that means that you checked your battery and charging system.

Originally posted by dlbryant1
Thanks for the help and all the good info. I will order a set a let everybody know if this fixes my problem.

Thanks again!!!

[dlbryant1]

Correct I have done a complete electrical check. The problem kept on getting worse so I had to check everything several times and on the last check the 2 plug caps had change resistance.

[Shuriken]

I had a 1974 Honda xl350 thumper that wouldn't spark. I got nothing despite anything I tried. After days and days I finally tried a different spark plug cap and voila, I got spark.

:P

I've been having perhaps some related issues on my XS. I checked the pickup wires today for the first time in a year or so - they are still fine after I repaired them once before.

I would really like to try the dyna coils, caps, wires, etc. I wonder if those who have installed the dyna coils notice a reliability / performance increase?

Ben

[strom]

I had to replace coil wires. Got em from an auto store, with the "caps" alredy on em. Since I mumbled something about 5k resistance, I got a funny gray wires with straight rubber "caps" that flex a bit. OK, it seals OK. The resistance was 5k-ish, and it worked.

LP

[cbird]

You do not actually need plug caps, especially for troubleshooting. Just wind the bare wire and screw on the little nut which comes with the plug. On mine, the connections of the wires to two caps were lame and had burnt and fell apart the first time I changed plugs so I went bare and it's OK. The other two haven't fallen apart yet, but I wonder what conditions are inside them and am tempted to chop them off too. Replacement caps I have seen have the same lame crimp junction.

One time I put my leg up on the crash bar and got a real jolt so I put plastic screw head covers on. The plugs, that is. Yes, the jolt went to my brain, FWIW