Want to make sure I have my coils wired correctly

[clintinga]

Hey guys,

I want to make sure my coils are wired correctly. I have a 75B and the coils are not original (well, at least the colors of the wires are not the same as on a wiring diagram). My coils both have a brown wire and a orange wire. I have a new wiring harness from mikes on the bike. I have both brown wires going to the red/white on the harness and the right orange is going to an orange and the left orange is going to a gray. Can anyone verify this is correct? I ask because it doesn't seem to be running on the left cylinder. Carbs are clean, static timing spot on, I have compression, I swapped the leads from the condensors and it didn't matter. I am getting spark to the left coil, so I assume it is wired correctly but I want to make sure. Any and all help will be greatly appreciated.


Thanks,

Clint

 

[retiredgentleman]

Yes, your wiring is connected correctly.

From what you say, I assume the right cylinder is running (getting hot). Make sure the left plug is not fouled................try a new plug.

Are you confident that you have the "right" side cylinder on the compression stroke, when the "right" (larger plate) points open?

If you are using old original type coils......................they had weak spark when they were new, and now with age, they may have even weaker spark. You should consider a new dual output coil for a much better spark.

Is your battery fully charged?

 

[clintinga]

Thank Retired.

The battery stays on a tender and is charging at the moment so I will check it when I am done.

Plugs were new as of Sunday. I am getting spark at the plug.

Am I confident that the right cylinder is firing on the right compression stroke? Not 100% but I am pretty sure. The right cylinder runs great and I would assume that it wouldn't run at all if the leads were switched. I could be wrong tho.

Clint

 

[scabber]

What happend I thought you had that problem solved ? Slight miss to not running.

 

[clintinga]

Scabber-

It ran on both cylinders the other day, (I think it was Sunday) and I left it alone till today. When I got home from work I was going to use the dead cylinder method to get the carbs synced and the left cylinder is not running again. I think it might be a carb issue but before I pull them off again I want to rule out everything.

I checked the coils tonight. 4.5 primary on both and 14.6 secondary on left and 18.5 secondary on right. They have the NGK caps on them but I am uncertain if they are the 5ohm type.

Clint

 

[retiredgentleman]

clintinga;

You can't chase carb and ignition problems at the same time. Your first post said the carbs are clean and now you say it may be a carb issue.

Stock igniton coils were 3.9 ohms primary and 8 k secondary. I have no idea what 14.6 k and 18.5 k are ???

What is the history of the carbs? Did you take them apart or did a PO say they were operating OK?

When an engine won't run, you have to go back to the basics.
What is the compression...............use a compression gage.
If you plan to get this bike running properly, take the carbs apart and replace parts as needed................float level is basic, it must be correct.

Only after you are confident that the carbs are 100%, then you can chase igniton problems.

 

[clintinga]

retired- Thanks for the response. Compression is 143 (cold) on both cylinders. I took the carbs apart, cleaned them in an ultrasonic cleaner, then used carb cleaner and compressed air to get everything out. So, I assumed everything carb wise was good. Then, wasn't getting spark on left cylinder, 5twins helped me figure out the plug cap was put on wrong. It ran on both cylinders on Sunday. I went out today to sync the carbs and it wasn't running on the left cylinder again. I knew the coils weren't original (well, I assumed so since the wiring colors didn't match) but they work even with the secondary difference between the two. The spark on the two plugs looks the same. I also found a bad float (a week ago) in the left carb and replaced it with a float (a week ago) that I check and know is good. I have quadruple checked the float height is correct. Even tho the right cylinder runs great, the plugs have only about 10 min on them and 8 of those 10 were at idle and its running too rich. I took the bowls off the carbs to look at the jet sizes to order new jets and the brass tube (in the bowl) that is for the overflow and it was clogged. So with all that, I have deduced that it is a carb issue.

With all that said,

What are your thoughts? Anyone else, please feel free to give advice.

Thanks,

Clint

 

[Patches]

When you pull the plug from the cylinder that is not running properly is it wet with fuel or dry? I would try making sure it is bone dry to start out, run the bike for a short bit and pull the plug again to see if it is wet with fuel. You may not be getting fuel to that cylinder due to a sticking float or other issue like a falty petcock.

I sent you a PM as well

 

[clintinga]

Patches,

Thanks for the idea. I pulled the plug today but don't remember if it was wet or dry. I will check again and let you know. The petcocks were rebuilt and they work.

Clint

 

[scabber]

If you pull the carbs again I think you can bench sync. leave the cables hooked up set the carbs side by side and read the carb sync thread I started use the sync method retiredgentleman suggested paper under butterflies.

 

[clintinga]

Thanks scabber. I searched for bench syncing, I understand what you are saying but I don't understand how to do it on mine? My both of my carbs have their own throttle cable.

Clint

 

[angus67]

just make sure they open at the same time, take up the same amount of slack in the cables, use th small adjusters near the throttle. you should be able to eyeball them close enuf to get your bike down the road in a satisfactory condition.

 

[Tomterrific]

Start the bike. Spray carb cleaner into the side that isn't running. If thet cylinder takes off then you know, the idle jet is plugged or there could be a horribkle vacuum leak.

Rev the bike. If the non running cylinder takes off you know, the IJ is plugged, horrible vacuum leak or carbs are very unballanced. It doesn't take a scientist to note the differences.

Coil. There could be an open/broken wire, probably at teh cap. Cut off a half inch of wire and install a SP cap with ZERO resistance. Zero because the resistance steals voltage. The engine will run with a broken wire, jumping the gap until the wire errodes to a length the spark cannot jump. You will still get spark at teh plug with the plug out side but as soon as the plug is under compression it goes dead.

tom graham

 

[XSLeo]

On the bench sync use a strip of paper about 1/4 inch wide and use it as a feeler gauge between the throttle plate and bore. Use the idle screws to set the throttle plates so they drag on the paper strip the same.
Leo