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Hello All,

I just purchased a 73 350 scrambler and it was basically a barn find but runs pretty well. My first challenge is the electrical system (very newb with electrical systems).

No lights work on the bike...headlight, taillight, speedo, tach. So far, I've rewired the taillight as there were broken/exposed wires, wrapped a few other exposed wires, checked all connections, clips and grounds. I also checked the two fuses under the gas tank, and they were good. Both headlight and tailight bulbs look good, actually pretty new. Still, no lights. I found this square white plastic component, near the fuses, that is cracked and may be bad. What is this? it has two blue wires going into one side, and a black/red wire on the other with the 4th connection spot open. It does not list what this compnent is on the wiring diagram. Can I just bypass this and wire the three together?

What else could cause a short? Blown speedo/tach lights? Indicator lights?

It would not let me attach a picture but hopefully the link below works. Any help would be appreciated so I can get on the road!

https://plus.google.com/?hl=en&gpsrc=gp ... 6217368037

https://plus.google.com/?hl=en&gpsrc=gp ... 6217368037

https://plus.google.com/?hl=en&gpsrc=gp ... 6217368037

https://plus.google.com/?hl=en&gpsrc=gp ... 6217368037

Justin

Hi Justin,

The first topic in this section guides you through how to add pictures. It's sort of a two-step process, navigating and selecting the photo on your computer and then pasting it into your message where you would like it to appear.

I think most of us will need to see the pictures and then we get rolling on curing your electrical problems. I could not open the links you gave me.

If you have fuses whose fusible links are intact, then you either have an open circuit (not a short circuit) or your problem is not in that circuit. A short on either of those circuits would open its fusible link.

The white thing you speak of could be a rectifier, and I say that because from a wire color standpoint red is usually a DC positive wire and black is usually a DC negative wire tied to frame ground. Two colored wires of the same color but having two separate connections on the same device is somewhat indicative of handling an AC voltage. A rectifier (if that's what it is) would be taking AC from the alternator and rectifying it to DC voltage. I am just guessing though.

I would be wary about just bypassing stuff until you know what it is you are bypassing and if it's the correct thing to do.

I think we have to establish if you have a battery on your bike, and if the battery is good. and work our way out from there. If you have no battery. nothing that runs on electricity will work until the engine is running and by virtue of the spinning alternator it will produce electricity to run the headlight and taillight.

Jim

Justin,

I think you'll find that the white thing you describe is a connector from the fuse to the horn and brake light switches.
Blue wire from the fuse feeding a red wire to the horn and another blue wire to the brake light switches.
It sounds like you have a Mototrans 350 Scrambler.
Do you have volts at the fuses?
If not, there is no power to the lighting circuits coming from the ignition switch.
If you do have power at the fuses, does that feed power to the light switch?
A quick check with a voltmeter should point out where your fault lies.

Jon

Battery is new, lights do not work while it is running (starts, runs, idles good).

I will check for voltage at the fuses and handlebar switch tonight. (I don't remember seeing the front headlight switch or brake light switch when I traced wires, ill look again)

If it is an ignition problem, can the ignition be taken apart to clean or could I spray contact cleaner into the key hole and work it thru?

Thanks for the fast responses!
Justin

Picture tool is working for me now:





Let me know if this looks bad or how to test. But since there are cracks, there is at least surface corrosion on the metal piece inside.

Justin

It appears the white block is a plastic housing that insulates an internal electrical block connection.

My thinking is that the red wire comes in and splits, from that one input, into two outputs. Without the white plastic the exposed electrical connections inside the block could short to the frame or some other grounded metal and that would give you problems!

If I am right about its function, when there is a voltage on the red wire you should see that same voltage on the two blue wires. There's nothing really contained within that could break or fail so for now I would ignore that as a suspect. Later when you have everything working you can seal that crack by wrapping electrical tape or putting heat shrink tubing over that white block.

Is your battery charged and is it presenting some volts if you measure across the terminals? I would start by checking that with the ignition switch in the off position.


Jim

[quote= Justinsch2444 ...
" Hello All, "

____ Welcome as our newest member, Justin !



" I just purchased a 73 350 scrambler "

____ If you're within the USA, then you must actually have a Mototrans-produced '350 ROAD' model with electronic-ignition, (although it's basically the same as a Scrambler-model) !



" No lights work on the bike...headlight, taillight, speedo, tach. "

____ Are we to assume that the brake-light also doesn't work, or not ?
__ Does the horn work ?



" So far, I've rewired the taillight as there were broken/exposed wires, wrapped a few other exposed wires, checked all connections, clips and grounds. I also checked the two fuses under the gas tank, and they were good. Both headlight and tailight bulbs look good, actually pretty new. Still, no lights. "

____ So did you also include trying a jumper-wire directly connected between the battery and any of the main lights, so as to make-sure that such a power-circuit can actually work (with all the other varied connection-lines bypassed) ?



" I found this square white plastic component, near the fuses, that is cracked and may be bad. What is this? "

____ That's merely-just a terminal-junction power-splitter that's meant for disbursing the battery's pos.output directly-to the fuses for the main-lights circuit and the horn & brake-light switch circuits !



" it has two blue wires going into one side, and a black/red wire on the other with the 4th connection spot open. "

____ Since it's just a mere power-splitter, it doesn't matter which of those wires get connected into any of it's four terminals ! _ The extra/4th terminal is intended for an optional turn-signal/fuse-circuit.



" It does not list what this compnent is on the wiring diagram. "

____ The diagram-author/creator must've assumed that anyone who could realize what the diagram represented, would naturally also realize that that system-wiring component is simply a mere wire-terminal/junction-box.



" Can I just bypass this and wire the three together? "

____ Of-course ! _ But why do that permanently ? _ It's a nice/neat method to connect-up all the load-circuits to the battery's pos.output ! _ Perhaps you may wish to replace it with another/new terminal-junction piece that provides a similar circuit-connection function.



" What else could cause a short? Blown speedo/tach lights? "

____ No type of burned-out lights can cause a 'short' !
By "short", I gather you must really/actually mean an 'open-circuit' !?
__ It seems I'm left to suspect that your handlebar-switch may have developed an open-circuit somewhere past the main-lights fuse, (but more trouble-shooting needs to be done in order to determine that for-sure, since I'm assuming the key-switch is still in stock order). ...
__ If you've already determined that it's indeed possible for the battery to power-up the lights when jump-connected directly, then next check to learn if the battery's voltage-level is available within the handlebar-switch. _ And if so, then check to see if the light-switch properly conducts the battery-power onward to the Hi/Lo.switch, (it's this point at which I currently-suspect that power has not gotten further transferred onward).

____ Let me know what you find up to this point, and then we'll move-on from here.


Hopeful-Cheers,
-Bob

[quote= Justinsch2444 ...
" lights do not work while it is running "

____ Do you conversely mean to indicate that the lights will work when the engine is-not running ?
If so, I'm thinking your stock dual-type key-switch has been connected-up incorrectly !



" (starts, runs, idles good). "

____ The 350-ROAD's electronic-ignition runs independent of the battery's electrical-system ! _ So whether or not the battery is able to power-up it's load-system, is irrelevant to the engine's ability to run.
__ The electronic-ign.system has to be killed in order to prevent ign.spark from being generated ! _ So the uncommon-type key-switch has to have a dual-type double-circuit (which provides two separate & independent switch-circuits). _ This type of key-switch is-not very common because it not-only closes one circuit when it's switched-on (as any common-type switch does), but it also simultaneously opens it's other switch-circuit as well ! _ So-thus when this dual-type key-switch gets 'turned-on', one of it's switch-circuits then 'opens' and-thus un-grounds the ign.circuit whilst the battery becomes allowed to feed the load-system, both individual ACTIVATED-functions completed at the same turn of the key !
__ To make-sure this intended double-action is performed correctly, we need to confirm that you have a stock dual-type key-switch and that it's still connected-up properly. _ Cuz if it's not, then it's possible that when connected-up in some-odd reverse-fashion,, then when the key is turned to it's ON-position, the battery would then instead become disconnected from it's load-system, (thus possibly explaining your no lights issue).
__ So by any chance do you still get ign.spark regardless of whichever key-position ? _ Or do you ever have lighting available whilst the engine is unable to start-up (due-to lack of ign.spark) ?



" I will check for voltage at the fuses and handlebar switch tonight. "

____ I'm now thinking that your key-switch is a likely source of switch-circuit malfunction, so I need to see a picture of it's two pairs of screw-terminals to see whether it's still the stock-type key-switch.
So it's pretty-much equally important to check & determine that the key-switch's two independent dual-circuits are both properly functioning as ought be expected.



" If it is an ignition problem, "

____ Now you're thinking "ignition problem" ?!?
The 'ignition' is a separate system in itself, completely apart from the rest of the entire battery-powered load-system ! _ So if there's any issue with the 'ignition', then it's due-to an entirely different electrical-circuit away-from your lighting-issue !



____ When did your lighting-issue begin to come to be noticed, before or after you-yourself started messing-around with it ?
Did the previous-owner also have any such electrical-functionality issue ?


Hopeful-Cheers,
-Bob

Hey Bob,

Thanks for the replies. Did some probing tonight with the multimeter and the ignition seems to be the problem as you indicated. All components have power.. handle switch, all lights and horn when the key switch is vertical in the off position (can remove key). When turned left or right no component has power. I took a picture of the wiring to the ignition:



The left connection is blue, top middle connection black ground to battery, bottom middle connection nothing?, right connection black ground to frame. Is this the correct wiring/type of key switch?

Thanks,
Justin

[quote= Justinsch2444 ...
" the ignition seems to be the problem as you indicated. "

____ But I never meant to indicate that there may be any problem with the "ignition" !
__ To avoid confusion, ya have-to state what ya actually mean and actually mean what ya state !
I'm left to assume that what you may really mean by "ignition", is actually a misleading-reference attempt to indicate the 'key-switch',, is that a correct assumption ?
____ Also, you leave me in a difficult position by ignoring the inclusion of any answers to any of my questions,, so-thus I'm left to assume, guess, and attempt to try figuring-out what's-what ! _ And that wastes time (if I even bother myself to remain involved with any unknowns).



" All components have power.. handle switch, all lights and horn when the key switch is vertical in the off position (can remove key). "

____ Funny that you hadn't noticed and reported that strange-oddity before.
That you have power-ON when the key-position is set to it's intended OFF-position, certainly indicates that battery/load-system is connected-up to the wrong switch-circuit of the dual-circuit key-switch !
__ Does the IGNITION also have power, or not,, when the key can be removed from it's switch ?



" When turned left or right no component has power. "

____ That revelation tends to indicate that the battery/load-system is rather connected-up to the particular switch-circuit that's supposed to be intended for grounding -('killing') the ignition.
So when you turn-on the key-switch to it's intended ON-position, then the battery is rather DISconnected from the load-system (instead of connected as normally-expected).



" I took a picture of the wiring to the ignition: "

____ I don't see any need to view a picture of the "ignition",, however after looking-over an enhanced version of your posted-pic showing what looks to be the original 'key-switch', I can obviously see that it appears the connected wire-terminals have been replaced.
Apparently someone who has overconfidence in their knowledge of electrical-system intricacies, didn't figure it worthy to bother making notes concerning which wires were originally connected to which switch-terminals, and consequently reconnected all the key-switch wiring back-up rather randomly (after renewing the wire-terminals),, thus ending-up with the electrical-system malfunctioning as you have discovered it.
(Since you didn't include any answer as to whether it was you or a PO who may've messed-with any suspect wiring, I'm left to surmise that it was likely your wiring-reconnection work that initiated the issue at-hand. )



" The left connection is blue, top middle connection black ground to battery, bottom middle connection nothing?, right connection black ground to frame. Is this the correct wiring/type of key switch? "

____ Evidently not,, cuz as for one-thing, all four terminals must each have a wire-connection !
__ What you need to do is disconnect the switch-wiring and then determine which of the four terminals are paired-together to provide the two separate switch-circuits.
So with the key-position set to the intended* OFF-position (* so the key can then be removed), you should then search-through the key-switch's four terminals for closed-continuity between whichever two terminals provide a closed-connection. _ Then that pair of terminals is intended for the ign.kill-circuit !
Then next, you should find that the remaining pair of normally non-connected terminals become connected when the key-switch is turned to it's intended ON-position ! _ As this-pair of terminals is intended solely for connecting the battery's neg.output to ground (for completing activation of the battery/load-system) !
__ So if you study the wiring-connection scheme of the unusual key-switch circuitry,, you should come to realize that either of the separate switch-circuits can become connected to ground, depending-on whether the key-switch is set to it's intended ON-position or OFF-position.
So-thus when the key-switch is 'turned-off',, the ign.circuit is then connected to ground, whilst the battery's neg.output is left isolated from ground !
And conversely when the key-switch is 'turned-on',, the ign.circuit is then DISconnected from ground, whilst the battery's neg.output then becomes connected to ground !
__ So after you've properly arranged all this unusual circuitry as it's meant to-be, then it's quite-likely that you'll then have your issue all straightened-out.


Hopeful-Cheers,
-Bob