Cyl. 3-4 misfiring

[Guest]

Guys; This is a great place of information, thanks for it.
Problem: Weak spark at cylinders 3 and 4, later plugs got fouled and lot of problems after that.

My bike is a GS1100E 1983, just headers and carb jetting.

I just replaced the coils with dynatek units to make cylinders 3 and 4 fires correctly, but they don't. I check the signal generator impedance and its ok. As per Haynes manual and doing the ignitor test the plugs 3 and 4 should produce spark as you touch the specified contacts and they don't.
Question: Which is better, replace with the original or install a Dyna 2000 system? Do I have to hurt my wire harness?
Which is your opinion about the source of the problem?
All inputs will be appreciated

[earlfor]

The first thing I would check is:
Take the gas tank off and make sure the left coil has its spark plug wires going to the 1 and 4 cylinders. (those are the outside cylinders. The spark plugs wires on the right coil should be connected to the 2 and 3 cylinders. (the middle two cylinders)

Earl

Guys; This is a great place of information, thanks for it.
Problem: Weak spark at cylinders 3 and 4, later plugs got fouled and lot of problems after that.

My bike is a GS1100E 1983, just headers and carb jetting.

I just replaced the coils with dynatek units to make cylinders 3 and 4 fires correctly, but they don't. I check the signal generator impedance and its ok. As per Haynes manual and doing the ignitor test the plugs 3 and 4 should produce spark as you touch the specified contacts and they don't.
Question: Which is better, replace with the original or install a Dyna 2000 system? Do I have to hurt my wire harness?
Which is your opinion about the source of the problem?
All inputs will be appreciated

[jacora]

Cyl. 3-4 misfiring

Earl;
The cables are in the correct position as you are saying. Left coil 1-4, right coil 2-3. Impedance on signal generator is 312 ohms.

[BassCliff]

Hey howdy hey!

Mr. jacora,

Let it be known that on this day you are cordially and formally welcomed to the GSR Forum as a Junior Member in good standing with all the rights and privileges thereof. Further let it be known that your good standing can be improved with pictures (not you, your bike)! :grin:

Perhaps you've already seen these, but I like to remind all the new members. In addition to the carb rebuild series, I recommend visiting the garage section via the GSR Hompage and check out the Stator Papers. There's also a lot of great information in the Old Q&A section. I have some documentation on my little BikeCliff website to help get you familiar with routine maintenance tasks (note that it is 850G-specific but many tasks are common to all GS bikes). Other "user contributed" informational sites include those of Mr. bwringer, Mr. tfb and Mr. robertbarr.

You might ask your question in the Tech Section to hear from the real gurus. I'm wondering, is is possible to have two bad plug caps? One bad plug and the other a bad cap? Stranger things have happened.

Thanks for joining us. Keep us informed of your progress. There's lots of good folk with good experience here.

Thank you for your indulgence,

BassCliff
(The unofficial GSR greeter)

[earlfor]

What I was trying to isolate is whether its an ignition problem or a fuel system problem. Since ignition fires in pairs 1,4 and 2,3 and your cylinders not firing are 3,4, then it cannot be an ignition system problem since the 1 and 2 cylinders ARE firing. Its possible its a bad spark plug boot on the 3,4 plugs, but not probable both would go bad at the same time. In your original post you said in testing the ignitor that the 3 and 4 plugs will not fire. It is not possible to do a test for the 3 and 4 plugs. You can do a test for the 1 and 4 plugs, or you can do a test for the 2 and 3 plugs, but 3 and 4 are on different sides of the ignition and not connected to each other.
So, I am still trying to clarify the problem.

BTW............this thread would likely get more responses if you were to copy and place it in the Technical section. General discussion does not normally cover tech.

Earl

Earl;
The cables are in the correct position as you are saying. Left coil 1-4, right coil 2-3. Impedance on signal generator is 312 ohms.

[jacora]

Earl, all your help is really appreciated