new problem...got caught in the rain... (Electrical?!)

[3Phase]

Book 'em, Dano!

I feel your pain because I don't have a car either, my bike is my only transportation and it's down for repair right now.

The backfire could have been a lot of things, probably from the TCI kicking a spark at switch-on or switch-off when there was fuel in one of the cylinders. It can be pretty spectacular.

Anyway, I'm starting to agree with Dbshea and it's not primarily an electrical problem. I've been trying to have you check simple electrical things that take more time to write and to read than to perform while you work them from the outside in as you remove covers and parts:

Side cover
Seat
Tank
Valve cover

Before you dive in much further you're going to need some manuals. If you don't have them already, here are a couple of links to the main '78 shop manual and the '80/81 supplement:-


XS1100oemManual.pdf 182MB


XS1100H-SH-LH_G-SG-LG_Service_Manual.pdf 35MB

I hope the share links work, Microsoft and Onedrive seem to be having DNS issues today.

Edit: Backfire/single spark is one symptom of a bad TCI.

[DiverRay]

Start with easy. Check the vents between 1/2 and 3/4. These are the top hoses and MUST be open! Next is look at the fuel lines, the bottom hoses, and make sure there are no kinks. If you have the stock petcocks, put them both on PRIME and see if it runs better. If prime works, pull the tank and CLEAN the outside of the petcocks. There is a little tiny vent hole that if plugged may cause the fuel to NOT flow. Prime bypasses this.
Let us know what you find.

[ERM83]

Could it be a carb issue?? When I yanked/checked them, they seemed fine....however, after the electrical checks, I'm thinking back to the shotgun-backfire. What carb issue would cause that??

[ERM83]

Ok....coils check out fine. Not only did I check them with a multimeter, but checked them with an inline spark tester...all good there. Checked the plug at the TCI...perfectly fine. I am at a loss...let's just say that if it was the other forum, there would be PLENTY of expletives in this post. WHAT AM I MISSING?!?! It's still running like garbage...I cleaned EVERY plug, checked EVERY wire...I have ZERO idea what it could be, and I'm about to lose my mind. also, the bike is my main mode of transportation, so I kind of have to get it going, hence the stress. My car is hurting at the moment as well. How could it be the carbs?! I just checked them on Sunday...they're pristine. SO. ANGRY....

[3Phase]

I'm pretty sure he just swapped the wires, 1&4, 2&3, but not the coils and plugs.

[Dbshea]

just checked that...plugs are good; wires are fine. This is driving me NUTS...it's SO NICE OUT today, too....

Just started it up, and spun it around my apartment parking lot...like I said, the neutral to first gear-bogging has gone away, but it's running like GARBAGE...just plain weak.

So you swapped the two sets of wires (1/2 hooked to 3/4 and 3/4 hooked to 1/2) and it exhibited the exact same symptoms. The right bank still ran "flat"?

Seems to me that if you verified the problem is NOT ignition related by swapping L/R then it is a mechanical issue and no amount of multi metering will prove anything of merit. If the symptoms followed the swap then I would agree with continue the electrical snipe hunt, but if the running condition was unchanged I would check the compression and make sure the carbs are spot on.

[3Phase]

What Ray said!

Ray used to work on these bad boys back in the day and pre-ordered his 1100 before they even made them, if there's ever any discrepancy between anything I say and what Ray says, listen to Ray and tell me to sit and spin.

[3Phase]

No, the valves and cams are different between the early and later heads. You can share the valve buckets, shims, valve cover, and some of the hardware dumafetchits but that's about it.

Technically you can put the '79 head on your '80 engine with the '79 cams to get a nice boost from the domed pistons with the smaller combustion chamber. With less piston-to-valve clearance you have to stay on top of the valve shim-to-cam clearances and try not to miss a shift but several people have done it and it didn't 'splode or anything.

[DiverRay]

Different heads between the F and G. G has a larger valve. Easy thing is pull the valve cover and measure the clearance all the way across. Write it all down in a chart like form, and if they are too tight write down what size is in each position so you know what size you need to bring it back to spec. The SHIMS WILL swap between them, so you may be able to see what you have around and not have to get any, if your lucky...

[ERM83]

It would well and truly suck but 'stuff' happens.

Have you checked the valve clearances? The valves slowly pound their way deeper into the head as they wear, that makes the valve stem stick up higher in the head and the clearance between the valve shim and the cam journal gets smaller.

When the valve clearances finally get too tight, the valve won't close and seat or it will only close when the engine is cold. As soon as it warms up, the valve can't seat, the engine won't run for squat and you'll go mad trying to chase ignition and fuel problems.

You can end up with a bunch of cool new parts and you'll learn a lot about installing, tuning, and troubleshooting too.

Ahhhh, right on! QUESTION: So, I completely went through the head on my SF...including cleaning and lapping the valves, stem seals, etc. Ran into a roadblock with that bike, and ended up having an easier time getting the SG running. Can I use components from the SF head on the SG??

[3Phase]

It would well and truly suck but 'stuff' happens.

Have you checked the valve clearances? The valves slowly pound their way deeper into the head as they wear, that makes the valve stem stick up higher in the head and the clearance between the valve shim and the cam journal gets smaller.

When the valve clearances finally get too tight, the valve won't close and seat or it will only close when the engine is cold. As soon as it warms up, the valve can't seat, the engine won't run for squat and you'll go mad trying to chase ignition and fuel problems.

You can end up with a bunch of cool new parts and you'll learn a lot about installing, tuning, and troubleshooting too.

[ERM83]

Thanks for all the help, everyone! I have to work until midnight...going to get back at it then. Gonna test the TCI first...there was a pretty big hole on the plastic fender behind it...that very well could be what happened. The coils are BRAND NEW...I REALLY hope it isn't those. That would suuuuuuuck.

[3Phase]

Alright! You're having fun now!

What is the pick-up coil resistance? It should be ~720 Ohms +/- 20%.

Remove the seat and use your Ohm meter on the wire pairs in the 4-pole TCI connector:
White/Red to White/Green for pick-up #1
Yellow/Red to Yellow/Green for pick-up #2



You can also do a ignition coil and spark plug swap test.

Pull the fuel tank
Swap the Orange and Gray wires for the coils
(Red/White wire is coil Primary + for both coils, Orange and Gray are coil -)
Swap the spark plugs -- 1&4 to 2&3 and vice versa
Swap the spark plug wires

If it's a coil or other high voltage problem the burbling babble will be on the left-hand side now instead of the right-hand side.

[ERM83]

Have you swapped plug wires left and right? They should be long enough to reach the opposite cylinders. Try that and see if the miss follows the ignition or stays with the cylinder. Additionally, I've had cracked porcelain on a plug that caused a similar issue under load, would not have known it was there if I didn't pull all the plugs.

just checked that...plugs are good; wires are fine. This is driving me NUTS...it's SO NICE OUT today, too....

Just started it up, and spun it around my apartment parking lot...like I said, the neutral to first gear-bogging has gone away, but it's running like GARBAGE...just plain weak.

[Dbshea]

Have you swapped plug wires left and right? They should be long enough to reach the opposite cylinders. Try that and see if the miss follows the ignition or stays with the cylinder. Additionally, I've had cracked porcelain on a plug that caused a similar issue under load, would not have known it was there if I didn't pull all the plugs.