Electrical Questions

[copeland3300]

Hey Guys.

I hope this is the right place to put this, rather than in Electrical repair or something...

Pictures here:
http://imgur.com/a/Pbgz3

I'm very close to getting my bike in working order. I sorted out most of the mess of a wiring harness that I had, which was chopped up and spliced and whatever else due to the bags and front faring. I think I took care of the big stuff, but I have a few minor issues/questions I was hoping for some help with. I've included pictures of the service manual's (Clymers) wiring section.

1) The red wire (A, picture 1) runs from the starter solenoid. It's what's connecting the + from the battery to the rest of the bike. Along the way it's got a connection (B, picture 1). I can't find anything in the service manual or on the bike to connect it to. Can I just chop it off or jumper it?

2) The wire (C, picture 2) I assume this is the ground from the - on the battery and that's it. My problem is that it's too short. Also the picture is a bit decieving, so I've marked the end of the cable, since it looks like it's connected to something else.

3) There's a tube (D, picture 2) running along the front of the battery box. I think it's for the vent of the battery, but I'm not sure.

4) What's the point of the fuse (E, picture 3) and what's it supposed to connect to? Is this the fuse that's shown on the red wire in the service manual (F, picture S2). Perhaps it's what's supposed to connect to that connector I can't figure out in question 1?

5) I can't seem to get the ignition switch turned. I get the key in all the way, but it won't go

6) The original throttle and swtiches had a plug on it with 3 wires coming out, a [Blue/White, and 2xRed/White]. I know there's supposed to be a black coming out of it according to the service manual. I borrowed the throttle/switches from the other bike, and it has [Blue/White, 2xRed/White, and a Black] coming out of it. The harness had a connector for the 3 plug switch, so it seems that way from the factory. What I did was rebuild the connector and added a black wire which runs to the black wire for the emergency engine shutoff switch. I soldered it and put on head shrink on the cable, so I think it's good.

I included picture 4 just for another angle if that's helpful, but it's not labeled.

Anyway, some thoughts would be awesome; you guys seem to have them for anything I've thrown at you thus far.

Thanks!!

[DGXSER]

Ok I will try to sort this out best I can from the pictures.....

1) The red wire (A, picture 1) runs from the starter solenoid. It's what's connecting the + from the battery to the rest of the bike. Along the way it's got a connection (B, picture 1). I can't find anything in the service manual or on the bike to connect it to. Can I just chop it off or jumper it?

There should be a black very thick cable/wire that connects the positive battery terminal to the starter solenoid. There is also that red wire with a connector on it, that feeds the auxillary connector, shown as item E in picture 3.

2) The wire (C, picture 2) I assume this is the ground from the - on the battery and that's it. My problem is that it's too short. Also the picture is a bit decieving, so I've marked the end of the cable, since it looks like it's connected to something else.

Yes, that is the main ground wire connecting the battery to the frame. Sound sliek it corroded off or got cut by a PO, you will need to replace it or somehow make one.

3) There's a tube (D, picture 2) running along the front of the battery box. I think it's for the vent of the battery, but I'm not sure.

I bet if you follow it it connects to the middle drive on the other side of the bike. Looks like the MD vent tube that should be running up under the gas tank, but can run where ever it works out for your bike, it simply vents to atmosphere.

4) What's the point of the fuse (E, picture 3) and what's it supposed to connect to? Is this the fuse that's shown on the red wire in the service manual (F, picture S2). Perhaps it's what's supposed to connect to that connector I can't figure out in question 1?

Yes, and it is simply an auxillary power source for whatever you use it for. 10 amps max.

5) I can't seem to get the ignition switch turned. I get the key in all the way, but it won't go

Well two possibilities here. First is youe key switch is corroded and dirty-stuck. Second is it is not the correct key. It is entirely possible the PO had to switch key switches and you did not the key to it.

6) The original throttle and swtiches had a plug on it with 3 wires coming out, a [Blue/White, and 2xRed/White]. I know there's supposed to be a black coming out of it according to the service manual. I borrowed the throttle/switches from the other bike, and it has [Blue/White, 2xRed/White, and a Black] coming out of it. The harness had a connector for the 3 plug switch, so it seems that way from the factory. What I did was rebuild the connector and added a black wire which runs to the black wire for the emergency engine shutoff switch. I soldered it and put on head shrink on the cable, so I think it's good.

Thsi is a variation over the model years. On the early models that was a three wire switch. The two red/white wires go to the stop-run switch. The blue/white to the starter button. The starter button serves to complete the grounding of the starter solenoid low side. On the early models, the switch made contact with the bars and that was the ground path. on the later models Yamaha installed a separate ground wire, the black one. So the black wire you created simply needs to be grounded.

[crazy steve]

Ok, in order....

1) The red wire (A, picture 1) runs from the starter solenoid. It's what's connecting the + from the battery to the rest of the bike. Along the way it's got a connection (B, picture 1). I can't find anything in the service manual or on the bike to connect it to. Can I just chop it off or jumper it?

If that B connection is two red wires, that's supposed to hook to your 'main' fuse which is not located in the fuse panel. This will be a short harness with a rubber fuse holder on it's end. You could jumper this, but your main supply will now be unfused and a fire looking for a time to happen. You still have the OEM fuse panel in place, I'd strongly recommend installing the 'upgraded' one TC sells and relocate your main fuse to that.

2) The wire (C, picture 2) I assume this is the ground from the - on the battery and that's it. My problem is that it's too short. Also the picture is a bit decieving, so I've marked the end of the cable, since it looks like it's connected to something else.

The cable you have installed is the jumper for between the top rear mounting bolt of the middle drive and the frame (the other end is a bracket on the cross-tube forward/below the battery tray). The battery cable will be longer. And where you have it connected to the frame, there's two bolt holes there, one is for the toolbox mount. Make sure you're not using that hole... and make sure you remove any paint under the connections or you'll have issues...

3) There's a tube (D, picture 2) running along the front of the battery box. I think it's for the vent of the battery, but I'm not sure.

Yep, that's the vent hose.

4) What's the point of the fuse (E, picture 3) and what's it supposed to connect to? Is this the fuse that's shown on the red wire in the service manual (F, picture S2). Perhaps it's what's supposed to connect to that connector I can't figure out in question 1?

That's an 'accessory' terminal and has nothing hooked to it from the factory. Yes, the fuse 'F' is that.

5) I can't seem to get the ignition switch turned. I get the key in all the way, but it won't go

Does the key match the switch? Both should have a number on them, make sure it's the same. If it is, the switch may need to be disassembled and cleaned.

6) The original throttle and swtiches had a plug on it with 3 wires coming out, a [Blue/White, and 2xRed/White]. I know there's supposed to be a black coming out of it according to the service manual. I borrowed the throttle/switches from the other bike, and it has [Blue/White, 2xRed/White, and a Black] coming out of it. The harness had a connector for the 3 plug switch, so it seems that way from the factory. What I did was rebuild the connector and added a black wire which runs to the black wire for the emergency engine shutoff switch. I soldered it and put on head shrink on the cable, so I think it's good.

The black wire is a ground, so don't connect it to the shutoff switch. That black wire should be connected to the switch housing and go to a chassis ground. It's there to give a redundent ground path for the starter switch.

[copeland3300]

Guys,

Thanks very much for your time and the info. I should clarify a little bit, and I have some follow up.

What size fuse should I connect to (B, pic 1)? Based on what Steve said I can just use what's on the accessory fuse?

Where is the connection on the middle gear case for the vent?

I'll adjust my wiring so that I'm going directly to the chassis from the black cable on the starter button.

[DGXSER]

The main fuse is a 30 amp fuse. As Steve stated, if that connector has two red wires, that is it's purpose. I had forgotten about that one.

If you look at the back right side of the engine, just above the oil fill cap, you will see two black hoses connected to the engine. The larger one, is the crankcase breather, the smaller is the middle drive vent.

[crazy steve]

What size fuse should I connect to (B, pic 1)? Based on what Steve said I can just use what's on the accessory fuse?

Where is the connection on the middle gear case for the vent?

The OEM fuse size is a 30 amp. Don't go smaller or larger. That 'accessory' panel won't work as the wires aren't big enough. The middle drive vent is located on it's top and faces to the rear. It's a smaller hose than the battery vent.

One big shortcoming to the Clymer manuals compared to the FSMs is they don't have the hose/harness diagrams in them, showing the actual physical layout/routing. If you go here: http://www.ringler.us/family/mybike.html you can download the factory '78 manual which will get you very close. There are some differences compared to the later bikes (wiring harness mostly) but this will clear up most of your questions....

[copeland3300]

OK I'll pick up what I need today at the auto parts store.

BTW, I also have the FSM, so I'll look at that as well.

Thanks again for the help, you guys are awesome. This project is made a lot easier with your help.

[crazy steve]

If you're going to install an inline fuse for your 'main', make sure it's rated for at least 30 amps. It should have at least #12 wire leads, preferably #10.

[copeland3300]

OK so here's how everything panned out:

1 found the inline fuse, but it was partly broken so I replaced with with a 12 gauge inline.

I found the correct battery cable and connected that.

I didn't find where to put the jumper from the engine to the frame.

I think the tube was for the old battery, because there was already a breather tube from the middle gear.

I replaced the fuse box with one from the store. The blue/w->blue/w fuse I put inline. The others are common to brown/tan so they all are fused to and then go to a common post where all the browns/tans connect.

I ran a black wire straight to ground for the starter button.

I disassembled the ignition as much as I could, but it's really stuck. I have no idea what's wrong. I rigged up a 4 pin molex connector where all the wires are soldered together to make a temporary "on" switch/key.

Once I connected the battery, I hooked up my special "key" (haha) and the indicators lit up which I was very happy about. The starter solenoid clicked when I pressed the button and the engine made two labored turns. I think my battery wasn't charged enough and/or is wrong for the bike, so I'll sort that out.

Anyway, progress!!

[DGXSER]

Good work!!! Yep, the battery needs to be pretty well charged to fire up the bike.

[crazy steve]

I didn't find where to put the jumper from the engine to the frame...

..The starter solenoid clicked when I pressed the button and the engine made two labored turns. I think my battery wasn't charged enough and/or is wrong for the bike, so I'll sort that out.

These two are probably related. That jumper is needed because the motor is rubber mounted, so trying to start it without the proper ground causes the power to seek 'other' paths; like through the cables and swingarm bearings. Some have melted the cables by doing this...

Don't try to start it until that jumper is installed...

[copeland3300]

Yeah, that's a good point, although in my defense it was something I overlooked rather than decided to forgo.

Now that I say that, I'm not sure if it's better to admit absentmindedness over poor decision making, haha.

[DGXSER]

think of it this way, we neither place blame nor forgive sins, we simply provide the best information to help you overcome the obstacle to your success, even if the obstacle is you.