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only 1 coil working

  • Thread starter Thread starter irishluck
  • Start date Start date
I

irishluck

Guest
So I got my shim job finished. Torqued the cylinder cover done, gave it fuel and tried to start. Wouldn't start at first. So I had to use starter fluid. Once I got it going it sounded alright, so grabbed my temp gun to measure the exhaust to see how hot it was getting. Cylinder 1 and 4 weren't firing. Which indicates the number 1 coil isn't working.

I also took off the headlight and disconnected all the wiring but I've got it all wired back up and still isn't working. Last time I fired the bike was about a month ago and both coils were working great.

Thinking maybe I didn't hook something up right?
 
The coils connections are under the fuel tank, so it is unlikely you disconnected them in the headlight

What bike? Do you have points?
 
Pull the tank and check the connector to the 1-4 coil. Might have snagged it loose when taking the valve cover off.
 
No fuel tank. Im still using the auxiliary tank.
Idk if I have points
Ive never seen anything about points

Its an 82 gs1100g

The bike was firings both coils just about a month ago. Right before I took the valve cover off to do the shim job.
The only thing Ive done since then was take the forks off and rebuilt them. Also removed the headlight and disconnected all the wiring in the headlight.

I reconnected everything and I have a few random wires but I dont think it has anything to do with the coils.

I fire the bike up with starter fluid with only the #2 coil working.

Now just to make sure. What is the firing order for the spark plugs on the cylinder.

Ive also already checked the wiring on the coils and it looks fine.
 
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Measure the voltage at the coils. If you have 12V+ then the problem will be either an igniter, the signal generator or some interconnect wiring. Nothing else in common with cylinders 1 and 4. That's assuming that you've actually verified no spark on those two cylinders and it's not a fuel issue.
 
No points on that bike

Check the coil ignitor wire color in your wiring diagram (orange?) and confirm that they are connected up by the backbone, behind the coils

There is no firing order as such, one coil fires 1-4, the other 2-3
 
I want to make sure which plug wires go on what cylinder is what im trying to ask, sorry.
Im gona go check the voltage now.
 
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Okay now im just lost at this point.

I went and checked the voltage and both coils are good on that.

I did the old " screw driver" in the plug test and all the plugs have spark. Fired the bike up again with starter fluid but still only running on one coil. Before I was having some
backfiring insues but since I did the shim job it hasnt backfired once.

Maybe I have 2 fouled plugs? But what are the odds that both cylinders on a single coil aren't firing and both have spark?
 
Sorry but you need to be a little more specific.

When you say that the voltage is good, what did you measure and where?

If you disconnect the plug wires from 1 and 4 one at a time and test them for spark using a loose plug against the cylinder head. Do you see spark on both?

What specifically makes you think that this is a spark problem? Did you simply assume that since 1 and 4 share a coil it must be spark?
 
I see a spark yer. I tested the coils at the positive and negative on the coil itsself.

Cylinder 2 and 3 are both firing no issues.
I dont think its a spark problem now on 1 and 4 though cause they both are getting spark after testing them.

Now I think its a fuel issue cause I pulled the plugs and there isn't any fuel on them and I don't smell any fuel.
Which makes me angry cause I just rebuilt those carbs, there spotless but obviously not now since 1 and 4 aren't getting any fuel.

Unless its got something to do with my shim job.
 
Fuel issue is what I was going with as well. Did you re-sync the carbs AFTER the valve adjustment. The adjustment can effect vacuum. Can you do a compression test just to make sure you didn't mess up the valve adjustment.
 
Ill have to go rent a compression tool but yea I can.
If its got good compression I guess ill have to redo the carbs.

Do you think thats prolly the only other reason though?

I mean the carbs were fine before the valve adjustment.
The coils both have spark, cylinder 1 and 4 are not firing and from what I can tell no fuel is entering the engine. Smelt the spark plugs and attempted to smell the engine cylinder and could smell no fuel.

Do you think its something clogged in the carb? or a vacuum issue?
 
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Do you have the ability to sync the carbs. If not, then beg, borrow, purchase or steal a set. It's really critical to get everything working at lower throttle openings. If you hold the throttle open at around 4000+ rpms do the cylinders ever come back to life?

If not, then get ready to strip the carbs back down.
 
Really need to be able to sync all 4 at the same time. It can be done with a two carb sync tool, but it's a much bigger PITA and the cost difference between the two is minimal. Not sure where you're located since you haven't updated your profile but if your in the USA then the dollar is pretty strong and the Morgan Carbtune's are pretty reasonable. Really one of the best synchronizers around. One other option is to see if there's a GSR member near by that has one. Again, you need to update your profile to indicate where you live.
 
Just ordered a motion pro 4 card sync tool. will arrive sunday
 
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irishluck said:
....I just rebuilt those carbs, there spotless but obviously not now since 1 and 4 aren't getting any fuel.

.....
Click to expand...

You say cyclinder 1 & 4 not getting any fuel because the plugs look dry. Good observation.
(So not an electrical-ignition problem. Not related to coils.)
(And probably not related to shims. Seems like you would have to have a shim way too big, zero clearance, that would keep valve open so no compression.)


Did you try loosing the drain bolt on bottom of each carb to see if getting fuel in the bowl?

When you say "rebuilt" carbs, I assujme you mean that you had the four carbs each off and apart from each other.
I don't recall the specifics, but I recall someone else rebuilt carbs, and thren was not getting fuel to bowl of one of the outside carbs.
Problem was something about not getting the carb bodys back in same 1-2-3-4 order, something related to those black gas tubes between the carb bodys. Someone else might have to explain that better.

Anyway, check to see if any fuel in the bowls. If no fuel in the bowls, then can look into that.


.


(And I don't think carb sysnc can be bad enough to not get fuel in cylinder.)

.
 
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Well I didnt need to buy the sync tool really.
Just checked if they were in sync and they all are without doing any adjustments

Just checked the bowls redman and they all have fuel in them.
And no I never took the bodies off the rails. I just tore each carb down and cleaned them by hand like I do all my carbs.

And just to rule out compression, I just tested the cylinders and there all in spec

Cylinder 1, 2 and 4 are 130psi and cylinder 3 is like 114psi.
So there all with in limits.

Im starting to fall back to the carburetors themselves.
 
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How did you check the sync if you don't have the tool? You'll have to re-sync your carbs every time you do a valve adjustment so it is a great investment
 
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