No ignition spark on #1 & 2 cylinder

[Mike Curtis]

Need some insight not getting fire in the #1 & 2 cylinder but getting fire in #3 & 4.

Ignitor box seems ok but maybe the pickup??

Need some advice on what to trouble shoot next.


1980 GS850

[blowerbike]

i have never seen a bad pick up unless it had been damaged.
swap your pick up leads around under the tank and rotate the engine with 19mm wrench with all the plugs out and plugged in to the leads and grounded.
see if you spark has moved to the other plugs.
may be a bad ignitor as this model should have a mechanical advance.

added
also check your plug caps/cut wire back 1/4" and re-thread.

[Mekanix]

Need some insight not getting fire in the #1 & 2 cylinder but getting fire in #3 & 4.
1980 GS850

1-2 ? 3-4 ? Am I right in understanding that you have one leg on each coil not firing ? or do you mean 1-4 2-3 as in one coil is not firing at all.

[Mike Curtis]

Yes one leg of each coil really strange

[Mike Curtis]

One more thing if it's a bad iginitor would I still get fire in # 3 & 4?

[Mekanix]

The ignitor is a pretty dumb box, as long as it gets a signal and is in good working order it will give an output. It can't decide between which cylinders it will fire, It only decides when it will fire one coil or the other.
But both are firing, so for now lets assume the ignitor is good.

With a 4 cylinder and having only two coils and having them both firing at least on one leg each. I would say that it narrows down the possibilities pretty good.

1 boots. resistors are shot or dirty
2 wire, shorting out or not making good contact in the boot or in the coil.
3 2 bad coil's ? unlikely but possible. A simple resistance test can tell you whats bad here.

And finally: low voltage. Do you have the coil relay mod done ?

What are you getting for voltage at the coils? it should be within 1-1.5 volts of the battery.
It could be just that the coil doesn't have the OMPH to fire when it doesn't have enough voltage and that combined with a high resistance in the leads and caps and plugs would cause it not to fire.

[Mike Curtis]

Thanks for your help..

Will report back as soon as I do some test I plan to go thru.
So far iginitor box is ok correct OHM readings.
Will check the wires and boots next they have some age on them and may need some updating.
Coils are old my go for an upgrade there but when I check them last they were good.
No I have not done any modifications to the electrical system other than replacing the stator a couple of years back. I installed a new battery within the last couple of months.

So the search begins.....

Thanks again

[Redman]

Given that one coil fires both 1 & 4 at same time based on a certain signal from the pick up, and that the other coil fires both 2 & 3 at same time based on a different signal from the same pickup. . . .

I think must have one problem specific to just #1 and another problem specific to just #2.
Is not any one thing that would effect both 1 & 2 without effecting all four.

Possibly the spark plug(s) them self or the spark plug cap(s).
THE caps are removable from the wire (just pull-twist) and they do go bad.

.

[Mike Curtis]

You hit it both plugs were bad and I cannot understand why the bike was running great within the last month or so.

Such a simple thing had me run up a gum tree.

Thanks for the help