My Electrics Thread

[magg]

Short answer yes, rest the plug on the engine and crank the engine for 10-15 seconds. Keep your hands clear.

[Man_Named_Dave]

Ok, plug No.1 was sparking so I decided to give it a try after discovering one of the hoses at the Y-piece had come loose.
It started chugging as if the fuel was starting to come through, but not actually catching. I checked the battery voltage and it's down to about 12.4v.

Is it worth charging it again and trying then?

[magg]

No need to charge the battery if voltage has only dropped to 12.4, a flat battery is more like 10.5 volts. I would try cranking so more with full choke. Empty carbs will take a little time to fill and fuel only flows while the engine is cranking.

[Man_Named_Dave]

No need to charge the battery if voltage has only dropped to 12.4, a flat battery is more like 10.5 volts. I would try cranking so more with full choke. Empty carbs will take a little time to fill and fuel only flows while the engine is cranking.

Good news- it lives! That ^^ sums it up- I was checking for spark off of plug 3 (affirmative) and it almost caught on 3 cylinders. I nearly jammed the lead in without switching off first!

Anyways it was showing above 14v with lights on and at 5k revs.
I want to do Neo's checks to ensure the alternator and reg/rec are good and he recommends a full battery, so I should charge it up for that and I'll post the results up later.

Many thanks Magg and Dave for the patient responses so far, I'm sure there will be more questions soon enough...

[Malc]

Dave, the 14v at 5K suggests the alternator is generating eletric and the reg/rec is okay in converting it to DC and limiting as required. Your system sounds healthy to me fella.

[Man_Named_Dave]

Firstly set you multimeter to resistance, if it has a scale pick 200, the smallest one.

Step 1

Disconnect the plug with 3 yellow wires that connects to the reg/rec loom.

Call one wire A, one B and one C.

Put a probe on the following

A and B: __________0.1
B and C: __________0.1
A and C: ___________0.1

Step 2

With the plug still disconnected set the multimeter to AC volts, 200 (lowest setting) should be fine.

Make sure battery is fully charged and start the engine (have the lights off)

A and B: __________24-25v
B and C: __________25-26v
A and C: ___________27-28v

Turn the engine off and reconnect the plug.

Step 3

Providing your regulator is wired up properly you can measure the voltage it is giving out at the battery.

Put the multimeter to DC volts, 20 will do.

Connect the -ve to the battery -ve and the +ve to the battery positive.

Measure the battery voltage with the engine turned off _________14.4v(12.7v)_____________
Measure the battery voltage with the engine idling______________14.4v(12.3v)____________
Measure the battery voltage with the engine at 5000rpm _________(12.3v)____________

Measure the battery voltage with the engine idling and lights on _____14.3v(12.5v)____________
Measure the battery voltage with the engine at 5000rpm and lights on ___14v(12.2v)_________

The blue readings were obtained this evening. The green readings were this morning. Strange that the readings were higher when I had been cranking the engine over to get fuel flowing.

[magg]

Was rect/reg DISCONNECTED when you measured the A-B-C voltages? Yes is strange that evening battery readings are lower, suggest you redo them.

[Man_Named_Dave]

Was rect/reg DISCONNECTED when you measured the A-B-C voltages? Yes is strange that evening battery readings are lower, suggest you redo them.

Yes, it was. I measured them at the block connector on the right-side front of the bike.

[magg]

What rpm when you measured the A-B-C voltages? Also measure the resistance between any of the yellow wires and the chassis with the rect/reg disconnected.

[Man_Named_Dave]

What rpm when you measured the A-B-C voltages? Also measure the resistance between any of the yellow wires and the chassis with the rect/reg disconnected.

Those voltages were at idle, so about 1100 revs. I was checking the yellow wires and they all check out, but one of them isn't snapping into the block connector perfectly, so my next step is to solder a spade onto that one.