Weak spark

[hyperballsmcgee]

Hello all, i am new to this forum and haven't quite gotten the hang of it yet so i apologize if i'm posting in the wrong area.

Anyways, i have a 1981 XS11 heritage "chopper" that's hardtailed and what-not. it seems like it has an exceptionally weak spark, especially on cylinder 4, which sometimes doesn't fire at all. across the cylinders the biggest gap that the spark will jump is MAYBE 1/8 of an inch, and it is a nice clean blue-white spark but it's not very bright nor will it bridge much of a gap. i know next to nothing about the 1100's, so would anyone say it's time to replace the coils on it? i would hate to spend the money on new coils for that not to be the issue..

[JeffH]

Howdy Balls, W E L C O M E
..... and yes, you posted in the correct place.

First question would be: how does it run? I assume you have been riding it. Start OK cold & hot? A little more info about the bike and any issues would be helpful.

What preventative maintenance items have been performed? That would also be helpful info to have. Could be as simple as be as simple as trimming back the plug wire a couple mm at the spark plug cap.

Jeff

[hyperballsmcgee]

thanks for the speedy response, the bike runs about as well as a 4 cylinder with a dead slug can run. IIRC the pilot jets are one step above stock. the bike has a 4-2-1 exhaust AP moto air filters. i haven't had the bike long, and it wasn't running at all when i bought it. only maintenance i have done is an oil change due to it being gas fouled from leaking float valves filling the cylinders and leaking into the crankcase.

[hyperballsmcgee]

i am not sure how to post pictures on here to show the filters and exhaust system

[DiverRay]

Welcome! To post a photo you need a "host site", photobucket, snapfish, etc. You can then copy the img location and past it to the photo link, the square box with the yellow sky and brown mountains below the rotate left arrow.
If it's only 4 that's not firing, it's probably the spark plug cap or the end of the wire. As jeffh said, you can unscrew the cap, trim back the wire about 3/8", and screw the cap back on the wire. I would also measure the resistance of the cap. They should be about 5K Ohms from the wire side to the spark plug side. If it's much higher, that's probably the problem.

[hyperballsmcgee]

[donebysunday]

Back stop

You need a stop on that seat, REALLY !!!!!
Don't want anyone getting run over by their own bike !
Once you get it running well the power will slide you right off that seat and onto the rear wheel.
If it starts hitting on all four all of a sudden again launching you onto that rear tire.
Great looking bike !
Not for me but looks meaner than HELL !

[hyperballsmcgee]

thanks! it's bit me once already! it's got a set of lane-splitter bars on it now and a fender is in the works, even hitting on 3 it's got enough to toss you back.

[hyperballsmcgee]

here it is next to my xs650