Coil problem! This one's wierd!

[renegade_xs11g]

the 'MONSTER' is a good name for this bike

after several problems and several pages of help

http://www.xs11.com/forum/showthread...threadid=14177

Thanks for all the help folks
let me know if in my area, coffee's on me!

still have a coil firing issue.....
no fire on 2/3 yes it's both, when cold
4-5 miles out, they start firing, (pull plug wire on either)
same with advance hooked or not

Carbs gone thru, many times (they're CLEAN)
performs very well, when running on all 4
I do need to re-sync but that's all

repaired P/U wires. Twice
gapped at .7mm (stop using IIRC folks, that's per CLYMERS)
voltages/continuity everywhere are within tolerance

I've NEVER heard of a coil working better when warm, ALWAYS worse
Checked TCI, all joints look good
but I could not get the board out of the case

Baffled, is the only word for what I am
My NEXT plea for help will be to an EXORCIST

[GtrMn]

Are you saying it only runs on 2 cylinders when you start it?...

[GtrMn]

And have you checked the wire going to the 2/3 coil...may be a short or grounded wire.

[renegade_xs11g]

That's right....2 cyl's
I've checked wires good from pickups to TCI to COILS

[GtrMn]

Not sure if there's a way to change 1/4 to 2/3 from the TCI...if so I'd try that to see if you get the opposite result. If not change out the coil. Always a few on ebay. or go to Excel coils. Doubt if the TCI is the problem. Heat wouldn't effect it in this case.

[prometheus578]

"Just to clarify..."

no fire on 2/3 yes it's both, when cold

Does this mean those cylinders are not firing....(meaning header pipes not getting hot), or does this mean those two cylinder are not getting spark?(Pull all the sparkplugs, stick them in the caps, lay the plugs against the head , and when cranking the engine, plugs 2 and 3 aren't sparking)
Is it no fire... or no spark?

[Ken Talbot]

Re: Coil problem! This one's wierd!

Originally posted by renegade_xs11g
repaired P/U wires. Twice

Just like triple cleaning carbs, sometime you have to go into your P/U coil wires three times to find all the breaks. Just because you found a break and fixed it doesn't necessarily mean you've found all the breaks. I chased one down for the longest time on SWMBO's 'H until I discovered a break underneath the crimp-style retainer just before the wires exit the case.

[renegade_xs11g]

OK ...still stumped

Started the monster yesterday, after running for a minute
2/3 pipes were cold, 1/4 warm

A couple of weekend's ago I had the plugs out and rolled it over,
spark on 1/4 was great, 2/3 a little weak,

I can unplug 2/3 while idling with no affect
I have tried to change coils (1/4 to 2/3, 2/3 to 1/4) but 2/3 won't reach
vacuum advance, makes no diff, runs the same either way
P/U wires, 2nd time repairing I took the harness from a spare set and replaced,
while riding I have only taken off wires from 1&2,
but I've swapped this wire and that wire as much as possible, with the same result

Now for the performance:
idle to 2k-2.5k a little boggy, lots of throttle to take off
2.5k-3.5k is only a little better, but popping a little, thru carbs / exhaust, yes, both
above 3k it changes to a deeper tone, and only exhaust
close to 3500 and above, ALL SMILES, runs like a well tuned machine,
all the way to redline, in 2nd, 3rd, 4th, I runs out of arse @ 6500 in 5th
I'd guess 90MPH, speedo quit working yesterday

All this time I've been chasing this.....been looking at coils
I think I need to look at them darn carbs again

The question is what part of carbs....
SOMETHING is obvioulsy WRONG,
but SOMETHING is OBVIOUSLY right

I'M STUMPED!!!!!!!!!!

[prometheus578]

"See if this helps..."

Ok... you say 2+3 have a weak spark. You also say you tried to switch the plug wires to check the coils, but they wouldn't reach, etc.
Ok.. play this game.(But it might get confusing)
You need to isolate the problem, and see which component is not fully functioning.
First, pull the plugs, (but leave them in the caps) and ground them to the engine. Crank it over.
You say you have good spark on 1/4, but weak on 2/3.
OK, switch the wires from the ignitor box going to the two coils and crank again.
If the spark to 1/4 is still good and 2/3 is still weak, then it's a coil problem.
If the spark to 2/3 in now strong, but 1/4 is weak, then you know the coils are good, but there's a fault with the magic box or the pick-up coils.
Reconnect the wires back to the coils in the correct manner.

(Now...retrieved from an earlier thread... as I'm too lazy to retype the whole thing)

You have a set of cylinders that isn't firing, but we know that the coils are both good, as you swapped the leads going to the coils and the problem switched cylinders.
The magic box sends two signals to the two coils. For some reason, the box is only sending out one signal. The question is... is it the box that's faulty?
The box's signals come from the signals sent by the two pick-up coils. So what we need to determine is... Is the box receiving TWO signals and only sending out one?(defective box) Or is it only receiving one signal from the pick-ups, hence only sending out ONE signal to the coils?(one defective pick-up)
Let's say the cylinders 1 and 4 are hot and 2 and 3 are dead. This means that pick-up coil 1/4 is good. (we still don't know about the box, nor pick-up coil 2/3)
So we switch the pick-up coils wires going into the box. Now the impulses from Pick-up coil 1/4 are going into the box on the 2/3 circuit. The box should interpret these as coming from pick-up 2/3 and NOW fire cylinders 2/3, but not 1/4. This will show that the box is doing it's job(Sending out signals on both circuits) and is good. It will also show that one of the pick-up coils is acting like your old girlfriend... she doesn't put out!
If, when you switched the pick-up wires, you still had the same live and the same dead cylinders, this means that both pick-up coils are putting out (though doing so now on each others circuits), but the box is only sending signals to the coil via the same one route, so now the box is your old girlfriend and not putting out like you want her too.

[TopCatGr58]

So after doing all of the above that Prom said, it also still sounds like your pilot circuit is messed up on cylinders 2-3!

The bike kicks in above 3.5K which is into the mains, so you're getting a restriction or lack of flow thru the pilot circuit somehow?

A short while back a fellow found out that he had a vacuum leak at the boots that was just enough to prevent the pilot circuit to flow, but did create enough when rpms got high enough so that it would still draw fuel thru the mains!

Did you put new synch port caps on? Are you sure your boots are leak free....around where they attach to the head? I'd investigate those first BEFORE pulling carbs, but you may still need to!? Good Luck! You may be chasing 2 problems, weak coil/ig problem AND carbs!?
T.C.

[Dragon Tamer]

I have to go with Top Cat here. It sounds very much to me like you have a vacuum leak. Having had the carbs off and on it is very easy to have developed one.
This has been posted before but here goes again. Use a small propane torch to find out if you have a leak and where it is. With the bike idling open the valve on the torch until it hisses, DON'T LIGHT IT!! Move the tip of the torch around the carb boots and sync caps slowly, if the engine speeds up anywhere along the line you have found your vacuum leak! Keep checking as you may have more than one.
I know, I know, this sounds dangerous. IT IS NOT REALLY, if you have a backfire and the torch lights, just pull it away and turn it off. Never spray a flammable liquid on the engine, if it lights you can neither pull it away nor turn it off!
I have found several vacuum leaks on many types of engines using this method and it works every time. Most of the time on the 1100's the leak is between the carb boot and the head and at low rpms they leak enough to prevent the pilot circuit from working, at higher rpms you either have enough air moving to provide the vacuum needed or the boots have been pulled tight enough to the head to mostly stop the leak.

[Dragon Tamer]

PS

When this same problem occured on my bike (vacuum leak) it always ran good warm, probably because the expanding head pulled the carb boots tighter and slowed the leak.
Keep us posted on what you find!!

[renegade_xs11g]

just a quick thanks for all of the idea's, that'll halp a lot......

it rained this morning, the bike had fallen over....soft dirt!
picked it up and let it set for a couple of hours, then I fired it up

a little hard to start, but after just a few seconds I noticed a lot of steam....still wet......all 4 pipes got hot

Gonna have to wait til next weekend for any more work,


Thanks again, John

[renegade_xs11g]

Re: "See if this helps..."

Originally posted by prometheus578

You have a set of cylinders that isn't firing, but we know that the coils are both good, as you swapped the leads going to the coils and the problem switched cylinders.

the problem never moved cylinders

[prometheus578]

Ok, so swapping the firing circuit still leaves you with 1/4 good and 2/3 bad, then it's fuel related. (I was just chasing his "weak spark")
Fuel related could be, like the other's have mentioned, plugged pilot circuit, vacuum leak, or valve clearances too tight, resulting in valves not seating.
Have you run a compression check?