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I HAVE A 97 HONDA SHADOW SPIRIT VT1100 ALL PLUGS ARE GETTING SPARK THE REAR CYLINDER IS MNOT FIRING. FRONT CYLINDER EXHAUST IS BLOWING WARM EXHAUST REAR CYLINDER EXHAUST IS BLOWING COLD??? NEW COILS PLUGS GAS CARB REBUILT?? ANY HELP WILL BE HIGHLY APPRCIATED THANK YOU. EMAIL [email protected] SORRY ABOUT ALL CAPS. KEYBOARD IS BROKE
 

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1983 Honda vt750 Shadow
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Measure the resistance on the pulse generators. 450-550 ohms usually.
If one goes bad it stops that cylinder from firing.
 

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1983 Honda vt750 Shadow
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The manual I have shows only one pulse generator for 1997 and up.
So if you only have one, that eliminates that as causing one cylinder failing.
It would feed signals for both to the ICM.
You did say all plugs are getting spark so ignition is not causing it. Unless one is weak.
Maybe the flooded plugs. Possible compression check would be good to know.
 

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1983 Honda vt750 Shadow
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Here is an idea, shut off the fuel supply and drain the carb bowls by loosing the drain screw on the bottom.
Clean the plugs and dry them, crank it with no fuel supply, and spray a little starting fluid into the carb with the dead cylinder. If it fires that means the ignition and compression is fine. Then go after a carb issue.
 

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On my '96 VT1100 ACE, a non-firing cylinder came from a clogged pilot jet, and perhaps other carb. issues. It might be worth pulling the intake air ducts and seeing if a bit of starting fluid gives clarity.

Also, be aware that the two plugs for each cylinder are connected in series. A bad connection at the plug cap, a fried resistor in the plug cap, or even a plug that's gapped too wide, can stop the whole show, sparkwise. This also means that testing for spark is a bit of a PITA. The high energy spark system isn't supposed to be run into an open circuit. Test for spark, with both plugs inserted, and a spare plug with solid ground to the cylinder under test. Even better, use an inductive pickup, like a timing light.

Check the high voltage wires.
 

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1983 Honda vt750 Shadow
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'97 Spirit 1100 - Chandler, AZ
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I HAVE A 97 HONDA SHADOW SPIRIT VT1100 ALL PLUGS ARE GETTING SPARK THE REAR CYLINDER IS MNOT FIRING. FRONT CYLINDER EXHAUST IS BLOWING WARM EXHAUST REAR CYLINDER EXHAUST IS BLOWING COLD??? NEW COILS PLUGS GAS CARB REBUILT?? ANY HELP WILL BE HIGHLY APPRCIATED THANK YOU. EMAIL [email protected] SORRY ABOUT ALL CAPS. KEYBOARD IS BROKE
If all the cylinders are indeed getting spark, then something is acting-up with the rear cylinder's carburetor.

I like to check easy stuff first:
-See if the idle mixture screw is open. 1-1/2 to 2 turns is in the ballpark. If it's closed or set too lean, no or too little idle fuel is getting to the cylinder.
If you increase speed to say ~1500 RPM, does the cylinder begin to fire? This would confirm the idle screw is set too lean or is closed.

-If that doesn't fix it, then I'd check to see if there's fuel in the float bowl. If none, then the new needle/seat are likely mis-adjusted or somehow stuck closed.
If there is fuel in the float bowl, then likely a plugged idle jet or passage.

Let us know what you find-out! Kevin
 
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