1978 xs1100e electrical problems

[jeng53]

Cranked yesterday and my tach was not working.
Revving engine did not brighten headlight beam

stator cover becomes magnetized when ignition switch is on

headlight relay clicks when battery (-) is connected

headlight is on when ignition switch is on regardless of the headlight switch position

Need some help for troubleshooting...

what do i need to check to isolate the problem?

[rainbowshooter]

Try cleaning all of the connections.

[jeng53]

have cleaned and checked connectors

checked the resistance of the 3 white wires (OUTPUT ALT)
they check out as 0.0 Ohms

the resistance of the brown to green is 4.0

with the connectors back together and the ignition on there is
10 volts between the brown wire and frame (also 10 v across battery terminals)

between the brown wire and frame it is than 0.4 V

with the bike running the voltage on the green wire or across the battery does not increase.

does that mean the alternator is bad?

the magnetizing test is ok

also the headlight relay gets very hot when the ignition switch is off! the yellow wire leading into relay has current even when switch is off is this the way it is supposed to function ?

[skids]

The 78E model has a switchable headlight if you havent started the engine. Once you start the engine, the relay is "latchable" meaning that the headlight stays on -- even if you try to switch it off, and it is "latched" until you turn the key off again. The tach is not working?? that is a sign that the stator is not working right (or at least one of the three phases), given that you are getting a magnet field.

[sksxs1100]

On my 78e, i can turn the head light on and off at will, running or not.

[jeng53]

well after much testing, i think the rectifier has to be bad. It fails the test in clymers in that b1 to W has the same resistance no matter which way its tested. Somehow that must be passing current from the battery to the HD light relay because it gets very hot even with the ignition off.. also with just the key on and engine not running the hd light is on and doesn't respond to the switch. Trying to find regulater in stock seems to be a problem.,

[skids]

Then it is not functioning as stock. You can snip the yellow wire leading to the relay and the "latching current" from the alternator will not bypass the hand switch. The headlight-on-whenever-bike-running mechanism is an annoying safety feature that is supposed to dummy-proof the bike. Problem with snipping the wire is that the runner light on the front still come on.

Originally posted by sksxs1100
On my 78e, i can turn the head light on and off at will, running or not.

[skids]

One thing that you should be aware of, testing the diode pack in the rectom fryer can be tricky. If you are using a multimeter that doesn't send much current, if will not "close" the diodes when in reverse, and will give you a false sense that the unit is faulty. You could be right about the rectifier however...

Originally posted by jeng53
well after much testing, i think the rectifier has to be bad. It fails the test in clymers in that b1 to W has the same resistance no matter which way its tested. Somehow that must be passing current from the battery to the HD light relay because it gets very hot even with the ignition off.. also with just the key on and engine not running the hd light is on and doesn't respond to the switch. Trying to find regulater in stock seems to be a problem.,

[jeng53]

Yeah.... New rectifier from Merriams cycle in Kansas came today and it plugged right in and fixed electrical problems.....now if I can only get my carbs running sweet. I have one cylinder that just doesn't want to be happy,.... #4 runs to rich and I keep overcompensating... if i set it low it acts like its starving for fuel on the low end... My bike must be female you just have to keep on till you hit the sweet spot!

[Redbaron]

Carb adjust

Glad to hear the rectifier helped. as for the #4 running rich, where do you have the mixture screws set, how smooth is the idle? What color is the plug, these may all be questions you've answered but i did not see them. Usually 1 to 2 turns out from lightly seated is sufficient if the jet has not been changed or is not clogged, over 4 turns out and you have jetting problems. At idle, adjust this for smoothest idle (by ear) and then test ride bike, note idle rpm before riding and then after. if they're are close, +/-100 then all is very close, ride. if it is noticeably different then a carb synch may be in order. also note if idle is smooth for a short period after a throttle blip or erratic. if it is smooth then becomes erratic your carbs may be loading up and may need cleaning or further mods. Also check plug color to be sure you have the right cylinder.