cylinders 2/3 not firing

[blackjaw33]

this is my first post on this site and i can already tell the technical advise is going to be very helpful. anyways, my 79 gs750 i just bought is having some cylinder issues. the number 2/3 are not firing. i replaced one of the coils after discovering it was bad. anyone have any suggestions on what my problem might be?

[GearHead]

Your either missing fuel or spark. You mentioned that you already replaced one coil, so I would start there. Verify your other coils are good. Check the voltage to the coils. 12v minimum. Spark should be a nice blue color. Also make shure that you are getting fuel to the carbs and to to the cyclinders.
Gearhead.

[Redman]

Blackjaw,

Welcome to GSR.

When you say "not firing", do you specifically mean no ignition spark, or do you mean more general that the cyclinders are cold?

Which coil did you replace? The one for 2/3 or the one for 1/4 ?

.

[gggGary]

Let's see if I have this; No spark on 2/3, you replaced that coil and they still aren't firing?

[Big T]

Points, condensor????

[blackjaw33]

the new coil is for 2/3. getting spark and fuel. my neighbor suggested the igniter unit?

[Redman]

the new coil is for 2/3. getting spark and fuel. my neighbor suggested the igniter unit?

Seems strange that neighbors sugest a problem with the igniter unit when you say you are getting a spark. Ignitor is part if the ignition system. Oh...wait....

A 79 would have originally had points (and condensor).

Was this running before? Or has not been running since having been worked on? (THinking maybe timing way off, if has been worked on).

.

.

[BassCliff]

Greetings and Salutations!!

Hi Mr. blackjaw33,

If you are sure you are getting spark and fuel, then the only other necessary ingredient is compression. There is a list of maintenance items that must be checked/repaired/replaced/etc so that these classic bikes run at peak efficiency. It's all in your "mega-welcome"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff