Replaced Handlebars, No Electric Start

[ABill]

Hi Guys, So i've replaced the handlebars and checked all the wiring, things seem to be fine, so that leads me to ground questions. I've sanded underneath the the switch itself, do I need to sand where the bars are connected to the bike as well? I can kick the bike fine, but get nothing coming from the push button switch. Any help?

PS. The bike is a 1980 SG if that helps at all!

 

[5twins]

On many of these, there is a ground wire in the left switch assembly that runs into the headlight. The right switch assembly (your start button) grounds to and through the bars over to the left switch assembly. So, you need to make sure both switch assemblies make good contact with the bars. The ground usually travels through the wire harness clip in the bottom half of the switch assembly. The ground wire itself is the wire under the Phillips screw on the far left .....

 

[ABill]

On many of these, there is a ground wire in the left switch assembly that runs into the headlight. The right switch assembly (your start button) grounds to and through the bars over to the left switch assembly. So, you need to make sure both switch assemblies make good contact with the bars. The ground usually travels through the wire harness clip in the bottom half of the switch assembly. The ground wire itself is the wire under the Phillips screw on the far left .....

So the ground is on the left side and not the right side? I just have to sand both down? The horn still works, as do the blinkers.

 

[Jim]

Open your rt switch back up. touch a wire to the starter wire and ground the other end of the wire to the engine (any bare metal that's tied to the frame). If it starts, you have a grounding problem with the handlebars. If it still wont start, you have other problems.
EDIT: It'a also possible you broke one of the wires to the kill switch while swapping.....

 

[5twins]

Exactly, the right assembly uses the ground in the left assembly. To get it, both assemblies must make good contact with the bars. This applies to the mid production range. Early models did have a ground wire attached to the handlebar clamp and very late models did have a ground wire in the right switch too. I just discovered this "new" ground wire added to the right switch housing on the '83 I'm working on. I don't know what year Yamaha added it, it seems not yet on your '80 model, and my best guess is it came along about 1982. If it's there, it will be attached to the screw that holds the start button assembly in the housing. The loom coming out of the switch will contain 4 wires instead of 3, one of which is a black ground wire.

 

[ABill]

I'll let ya guys know how we work out !

 

[Jim]

The horn still works

That sorta indicates good ground at the handlebars....
It works the same as the starter switch... power comes in and completes it's circuit through ground. If you didn't have a good ground on the left switch, neither should work.

 

[ABill]

That sorta indicates good ground at the handlebars....
It works the same as the starter switch... power comes in and completes it's circuit through ground. If you didn't have a good ground on the left switch, neither should work.

Well seeing as the ground goes directly into the switch on the left side, wouldn't it be ground regardless? The right side has to go through the bar to the last side to get grounded correct? I'm new to this electric business, so forgive me if I'm completely off in that.

 

[gggGary]

The new bars wouldn't by chance be black ?

 

[5twins]

Yes, correct. The left switch assembly is grounded by a wire. The right switch assembly must get it's ground from the left assembly by going through the handlebars. The whole left switch housing is grounded because the ground wire attaches to it with a screw. But often times, the paint on the housing extents into the cut-outs that clamp around the bar. That's why that wire loom clip is what is relied on to carry the ground into the bars. It's plated steel, not painted.

 

[Jim]

wouldn't it be ground regardless?

Yeah... your right. My bad. the ground wire is built into the left switch housing.....

 

[ABill]

The new bars wouldn't by chance be black ?

Yes sir, they are! I know it's a ground issue, just a matter of figuring out how the bike is grounded. From the sounds of it, I just have to remove the paint from left side and magical starting should resume! It seems my right side is connecting with the bar, but the left isn't picking it up to ground it. We shall see!

 

[ABill]

Yeah... your right. My bad. the ground wire is built into the left switch housing.....

No worries man! I've been lost since last night on this, so glad to get some help!

 

[peterg]

Your right switch assembly should have 4 wires - two which are connected to one end of the starter button. One (black ?) can be used to ground the starter button except the wiring loom connector does not have a corresponding wire. If you want to ensure you have grounding to your starter button add a wire to the loom connector and fasten the other end to a ground point - perhaps the top engine mount that already has a wire connected to it or at a ground in the headlight bracket. This engine mount wire ensures that there is connectivity between the frame and the engine.

Note: I am working from memory on the switch wiring. To make sure that the start switch has a ground wire test for continuity between the blue/white wire and black (?) wire when the button is pressed. There should be no continuity when no pressed. The brown and red/white wires are for the kill switch and should have continuity when the switch is on the run position. There should be no continuity when in the off positions.

 

[ABill]

Your right switch assembly should have 4 wires - two which are connected to one end of the starter button. One (black ?) can be used to ground the starter button except the wiring loom connector does not have a corresponding wire. If you want to ensure you have grounding to your starter button add a wire to the loom connector and fasten the other end to a ground point - perhaps the top engine mount that already has a wire connected to it. This engine mount wire ensures that there is connectivity between the frame and the engine.

Note: I am working from memory on the switch wiring. To make sure that the start switch has a ground wire test for continuity between the blue/white wire and black (?) wire when the button is pressed. There should be no continuity when no pressed. The brown and red/white wires are for the kill switch and should have continuity when the switch is on the run position. There should be no continuity when in the off positions.

There's only 3 wires on my right side. I think the ground is in the left.

 

[peterg]

Well then my idea won't work. My replacement switch has 4 wires - one of which I'm using as the stop switch ground - and I could have sworn my original switch had 4 wires. The Haynes diagram also shows 4 wires for the SG but the number of wires varies by year (according to Haynes).

 

[ABill]

After a ton of sanding, we got a Click! Unfortunately the bike died on me over this time period. I went ahead and bought a battery and a tender, just to have some backups. Spent a few days messing with the damn thing.