Did I do this right?

[dpep]

I was test riding my 850 that has been having fuel flow/carburetor issues and two cylinders dropped completely out. I made it home and when I pulled the tank this is what I saw.

There was not enough slack wire to just put on a new connector and have it reach. So instead I spliced in a short section of the same gauge copper wire. Pigtail splice, soldered, liquid tape, then electrical tape on both ends.

Now the bike starts and runs fine until a little over 3000 rpm when it suddenly bogs down. It is quite possible, maybe even likely, that this is a continuation of my fueling problems and will resolve with a carb rebuild now underway.

However, this particular problem only occurred immediately after the coil wire break and fix; and I am not a big believer in coincidences. Also many years ago I had an 850 giving similar symptoms that near drove me batty until we found that one of the coil wire connectors was intermittently shorting against the frame. I can't see any wire or connection exposed and I have the wires away from the frame. But the sudden and predictable nature of the drop has me wondering if I did this right and if there is something different/further I could have or should have done.

I obviously won't be able to know for sure until the carbs are back on. But in the meantime it doesn't hurt to inquire of those more knowledgeable than one's self.

 

[bonanzadave]

Might have just compounded an already typical GS situation. Old wires and splices in these old bikes build up resistance and voltage drops that cause problems all over. My coils would only get 9VDC when I hit the start button. After a coil relay mod they got full battery voltage and start ups are now instantaneous !

 

[dpep]

Might have just compounded an already typical GS situation. Old wires and splices in these old bikes build up resistance and voltage drops that cause problems all over. My coils would only get 9VDC when I hit the start button. After a coil relay mod they got full battery voltage and start ups are now instantaneous !

Would the two soldered splices in total have much more resistance than the crimped spade connector they replaced?

The bike is an '81 with 24,000 miles on it. It's appearance and the paperwork research I did would indicate that is probably an accurate number or close. Somebody did not do well by the carburetors along those few miles though. I suspect it may have sat for long periods of time with fuel in the system.
...

 

[bonanzadave]

Would the two soldered splices in total have much more resistance than the crimped spade connector they replaced?

Dont know. Put a meter on your coil terminals and press the start button......If it drops to a couple volts less than battery voltage that's not a good thing. Nor are the carb issues you're dealing with but the carb rebuild is diffidently a step in the right direction.

 

[Brendan W]

Yeah, check the voltage at the coil side of the splice and it could be the other wire is acting up.
Measure the voltage at the coil side of the supply wire. Ideally no more than a Volt below battery terminal voltage.
On the ground side measure the voltage drop across the splice/connector.
90% of carburettor trouble is electrical

 

[Redman]

I would say you “did good”.
two solder connections probably less of a problem than one of those kind of crimp connection.

org/wht wire on way to coils, I would think.

don’t think your upper rpm problems related to this/these connections.

with any ignition strangeness: don’t forget to ohm check spark plug caps (about 5k ohms each).

 

[Gorminrider]

There was not enough slack wire to just put on a new connector and have it reach. So instead I spliced in a short section of the same gauge copper wire. Pigtail splice, soldered, liquid tape, then electrical tape on both ends.

Not a problem if the soldering was good on bright wire... Just ugly. As to "resistance" your best test on something like this (connections,switches and other low resistance tests) is to get a voltmeter, put prods one EACH SIDE of your connection* and voltmeter should show 0 volts=0 resistance......I recommend the pricier 3M general usage black electrical tape for stuff like this-the end of the wrap doesnt come loose and flap after a week...

* try to get the red + prod onto the side "towards" the battery black towards ground but your (digital) VM will tell you with a Negative sign if you have it wrong but still read ok as to volts

 

[dpep]

Still working on my carb issues but I need to start tending to the electrical ones. I think I may be misunderstanding how I should be doing this check. With the switch turned on, engine not running, starter not touched the voltage across the battery terminals is 12.7. The voltage across the coil terminals is 7.5 (on both coils). There is a 5V drop from battery to coil BEFORE hitting the starter. From what you guys are telling me that should not be. Or have I just misread your instruction?

 

[Nessism]

That's a huge voltage drop. A couple of volts loss is okay, but not 5.

You may need to do some harness clean up work. I've never found a really good way to do that though, since it's tough to clean down inside the terminals. One other option is to do the relay-coil mod. It's pretty easy, and assures you will have full battery voltage at the coils.

 

[Gorminrider]

dpep,

Now the bike starts and runs fine until a little over 3000 rpm when it suddenly bogs down

reminds me very much of exact same symptoms on a Honda....and it was IGNITION. ..

You have spark below 3000 rpm so my first suspicion would be the timing sensors because they are simpler and timing is a strong possibility) the Black Box and coils. Your earlier troubles support my suspicion and now this voltage at the coils...You may not even have these "sensors on your crank shaft"- timing may be internal to the Black Box...
To test ignition: FIRST Disconnect your headlight and peripheral circuits at fuse ... It will give you more battery time and simplify testing.
Suspicion (and it's still just a "suspicion") is that you seem to be dropping 2-3 volts more than you should (unless your battery is weak -WHEN the coil is "on" and displaying such a low voltage... If you have a spare car battery.) Because a voltage drop test is relevant within the SUM of voltage drops. IE: if your battery voltage is 11V when you test the coil at 7.5 it's not out of line as a proportion of the circuit.But if Battery is 12.7 and coils 7.5 that is pretty poor.

...When you have the Kill switch to ON, the + power flows through the fuse, the switch, the coils and the black box to ground...so check the voltage drop along the wires between those and "across them" ...I recently posted a diagram per testing Voltage drops but the main thing is to cross the simple things like wires, connectors and switches off the list FIRST and then puzzle between the $$$ bits- Black Box and Coils...

 

[Nessism]

dpep

Take this with a grain of salt since I've yet to prove this method for myself, but if I were to restore another electrical harness, cleaning the connectors, I'd get me one of these Harbor Freight Air Eraser/Etching kit and shoot some baking soda through it and clean out all the electrical connectors. Baking soda is pretty safe, and a simple water, followed by WD-40 rinse, should clean out any remaining soda. There are some youtube videos showing it's effectiveness.

https://www.harborfreight.com/air-eraseretching-kit-69277.html

 

[bwringer]

You should be checking the voltage between the power wire on the coil (orange/white, I think? It's the same color on both coils) and a good ground. That will tell you if there's a voltage drop in the power supplying the coils.

 

[Gorminrider]

Remember that the voltage drop across just the coils doesn't include the Black Box that is in series with the coils to produce the spark...solid state devices generally use power too. It can be very misleading to try to get the voltage drop "across the coils" to = the battery voltage.