78 GS1000E 2&3 cylinder not firing

[drewandkellie]

I have a stock 1979(not a 78 as I put at the top) G1000E that is giving me throuble. I bought the bike and the carbs were leaking badly. I rebuilt the carbs anb fired it up. The bike runs but only on the two outside cylinders even when revved up to 5000rpm. So
1- I changed the plugs. result NO CHANGE
2- put on a spark checking plug and clipped it on a cooling fin.
Cylinder 2 is sparking like crazy, while cylinder 3 barely eeks out a lame spark every 10 seconds.
3. checked the points and gapped them at .3-.4mm as specified. (I have never worked with points before so I am at a loss as to what exactly what I am looking for other than gapping them.)

What throws me is that cylinder #2 is getting all kinds of spark but it's exhaust pipe is just as cold as #3 which is getting no spark at all. I am confused. Ignition? Coil? Points?
Any ideas?

Drew

[salty_monk]

2 & 3 are controlled by the same coil so that's one thing to try, switching them over to see if the problem moves with it.
You should also check you have good voltage at the coils (kill switch on) & check out the condensor for that side too.
If 2 is getting sparks & fuel but not firing then the only other thing it could be is timing....

Are your points set up on the correct timing marks etc?


Dan

[drewandkellie]

I like the switching coils over idea, but I'm unsure how to do that. is there a simply way?

[rpickle]

Move plug wires, 1 and 2 then 3 and 4. Should reach.

Good luck.

Rick

[drewandkellie]

she wouldn't start that way.

[chef1366]

Take off the tank and find the wires that go into the coils. Two on each. With the ignition on and the kill switch on there is a hot wire that goes into each coil. Leave that one alone. Take the other wire(s) and swap them out. Now the 1&4 coil becomes the 2&3 and vice versa. Swap out the plug wires and see of the problem goes to the 1&4 cylinders. If yes your points need work.

[salty_monk]

The wires you want to "leave alone" will likely be Orange & white.

The ones to switch will likely be white & black with a yellow stripe from memory.

If you still have stock coils it will be difficult to do without cutting the wires as the plugs are configured so you can't "mix them up" by accident.

Just swapping the plug leads (HT) will mean it's firing at the wrong time so it won't start, you will be able to see if you now get good spark by eye though doing that.

Dan

[drewandkellie]

spark on all four cycliders, still not firing

Ok here is the update. 79 GS1000 Stock That wasn't firing #2 or #3 cyclinder.
installed Dyna-s
Installed new 3 ohm cils
installed new 7mm wires
Timed with timing light. Perfectr
Result: Good Spark on all four cyclinders. That's One problem solved

BUT !! #2 and #3 head pipes still cold(By the way this thing runs pretty well on Two cylinders)
I Sprayed starting fluid in the back of #2 and #3carbs causing the Idle to raise a little! OK, I figure 2 and 3 are starving for fuel. Why, Varbs were just rebulit and I have fule in the float bowls. So I Sprayed intake manifold#2 and idle raises. Aha Leaking manifold. Can this small lose of suction prevent the cylinder form firing?
AM I right OR am Going looney from Smelling gas and Starting fluid?? Is there nay thing else I could be missing?
Also, Where do I get new manifolds and o rings? Alpha sports shows them at over $30 each.

Thanks I needed to vent!

[drewandkellie]

Fixed!

Just wanted to close out this thread on a victorious note.
It was not one problem it was three!
1 Bad Coil (tested fine but didn't work)
2 Leaking manifold o rings
3 The biggie, BLOCKED PASSSAGES IN CARBS.
I tried an old set of carbs from frankensuki and that was the ticket. Don't know what was up with my stock carbs, must have a block somewhere but for the life of me I couldnt find it. Hope this helps the next guy.
Oh well the sun is shining and I need to run this bike. Thanks for all your help.

Drew