safety mechanism preventing ignition?

[Alex M]

Hi,

Does anyone know how to bypass the safety mechanism(I was told the green and yellow wire) which would prevent startup?

I will explain: I have a 1981 GS750. Because it was having problems starting up, I replaced all 4 spark plugs today.

After replacing the plugs, I tried to start the bike. It started to fire but then within 2 seconds cut off. Now the ignition switch does nothing when pressed(the battery is good-thats not the problem).

A guy at the Suzuki dealer explained that there is a safety mechanism which sometimes fails and it needs to be bypassed. He said it is connected by a green and yellow wire found with all the wires behind the headlight. He also explained how to bypass it, but I did not fully understand the explanation. Does anyone know how to do this?

thanks for any help!!!

Alex

[posplayr]

simple fixes

Get a schematic for your bike. Bass cliff probably has it. The clutch might have a switch that is wired in series with your ignition. To by pass it simply disconnect the wires going to the remote switch's and connect the harness side back together. The safety switch simply breaks the path like if you try to start the engine with the clutch out as an example.

If the only one you have is the clutch then you can remove the wires where they terminate at the main harness which is in the headlamp bucket. Follow the color code and you will figure it out. The clutch is probably two separate bullets.

Pos

[salty_monk]

I don't think there's anything else on an 81, just a clutch switch. They are identical to the brake light switch on the other side. Small parts & quite apt to wearing out...

The harness even has the correct fittings to make it a very simple "unplug - replug" job. Takes about 5mins including removing the lamp...

Dan

[BassCliff]

Hi Mr. Alex M,

Did you blow a fuse? Unless the clutch safety switch has been disabled, you have to pull the clutch in order to start the bike. But if you get nothing when turning on the ignition, then check/replace your fuses. If you do get activity when turning on the ignition switch, maybe your start button is dirty? Let's hope you don't have a more serious problem.


Thank you for your indulgence,

BassCliff

[Guest]

Easy to bypass. Take out the headlight. Follow the wires from the clutch into the headlight bucket. Unplug the switch and plug the remaining wires into each other.

[BassCliff]

Hi,

So far, I've left my clutch "safety switch" intact. It's kept me from doing something stupid a couple of times. At least on my motorcycle anyways.


Thank you for your indulgence,

BassCliff

[Alex M]

thanks for the suggestions! i will try and rewire it and report back!

[Alex M]

update(with photos!)

my 1981 gs750 with 27,000 miles wouldn't start, so i replaced the spark plugs. when i tried to start it with the new plugs, she cut out after 2 seconds and now there is no response when the started button is pressed.


CLICK ON THESE PHOTOS TO ENLARGE THEM.

[Alex M]

more photos

this is a shot of the fuses. it looks like they are all still ok(?)

[Alex M]

this is what i see when i pop the headlight out.

[Alex M]

photo of wires from clutch

[Alex M]

this is where the wires from the clutch go(i think)

am i following these wires correctly? what should the next step be?

regarding the clutch safety switch: since i bought the bike a few months ago, i have always been able to start the bike without the clutch in. i now understand that the clutch should always be pulled in when starting the bike(even when it is in neutral).


thanks again for all the help.


alex

[Steve]

this is a shot of the fuses. it looks like they are all still ok(?)

Sorry, but electrons don't believe in looks. You have to test the fuses with a test light or an ohmmeter to verify that current is actually getting through. Many years ago, I lost power while traveling in Arizona on a hot day. All the fuses looked good, but the ignition still did not work. Put in a different fuse and it worked. I found that the wire inside the fuse had broken up under the metal cap, where I could not see it. If I tapped the fuse, I could see the wire jiggle inside.

since i bought the bike a few months ago, i have always been able to start the bike without the clutch in. i now understand that the clutch should always be pulled in when starting the bike(even when it is in neutral).

Evidently your bike has already had the clutch switch bypassed. It is always good practice to pull the clutch when starting the bike, I just don't like to be forced to pull the clutch. If I see that it's in neutral and verify it by rolling the bike, there is no real need to pull the clutch. For the '81-and-older bikes, it makes it easier to play with the choke knob while pressing the starter button. For the '82-and-newer bikes, you can still pull the clutch while thumbing the choke lever easily enough.

.

[Alex M]

fuses are not the problem

thanks for the advice Steve, after reading your reply i replaced all 5 fuses (4 10amp, 1 15amp), but the starter is still unresponsive.

if the fuses are not the problem, and the clutch switch has already been bypassed(i have always been able to start the bike without the clutch), then what is next? bad starter?

i am willing but inexperienced, should i take it to the mechanic? of course thats never fun.

again, thanks for reading.

[LarryA_Texas]

starter button

thanks for the advice Steve, after reading your reply i replaced all 5 fuses (4 10amp, 1 15amp), but the starter is still unresponsive.

if the fuses are not the problem, and the clutch switch has already been bypassed(i have always been able to start the bike without the clutch), then what is next? bad starter?

i am willing but inexperienced, should i take it to the mechanic? of course thats never fun.

again, thanks for reading.

Lets have a quick recap of terms in use here before we go any further. Ignition is what makes the gasoline in the engine burn. Don't confuse that with the starter...the starter is an electric motor that turns the engine while the igniter box sends a signal to the coil and then to the spark plug to ignite the fuel. (the 'ignition' in your car, where you put the key in, is really just a combination power and starter switch)

Ok...if you always could start it with the clutch lever released then the safety switch has probably already been bypassed. But maybe not. I'll have to assume that once the starter failed you at least TRIED to start it with the clutch lever pulled in. If not, go try that first.

Second...it's very unlikely that your starter suddenly failed. Sure, it's possible, but it's an electric motor and will wear out slowly. It will likely turn the motor slowly before it just quits working.

So, the obvious conclusion is that the starter isn't getting any electricity in the first place. You really need a wiring diagram and some practice with electricity. Since you asked someone to tell you if the fuse was good I'll assume your experience level here is very, very limited. You will have a very difficult time working on any electrical problem until you get some basic knowledge of how these circuits work.

Electricity has to have a loop. A complete circle (circuit) from + to -. The positive, +, brings the electricity to the negative side...which is most often the ground...on in the case of these motorcycles, the frame itself.

If the clutch has a safety switch, then the wire from the starter switch goes to the clutch, then to the starter solenoid. If the circuit is broken at the clutch switch then pressing the starter button won't start the bike because there isn't a complete circuit. On most of these bikes, the kill switch (right handlebar) is also in that loop so if it's OFF the starter will not engage.

To bypass the clutch switch you have to complete the loop. So the two wires that go to the clutch handle can be connected...all they have to do is touch. It's easier to trace the wires from the clutch switch into the light bucket, unplug them from the wiring harness and then plug those two wires into each other. That completes the circuit without the clutch switch being able to interrupt the flow. A slightly more complicated way to solve the problem would be to actually fix the switch. I can't recommend you try that.

Now, to solve your problem...

You need to see if you can start the bike without the starter button. If you can, it's the button itself, which can be fixed, but you need some talent in this area. It's more complicated that checking for a blown fuse.

But what you can do is trace the wires from your starter motor to the starter solenoid...and try to jumper it to see if the starter works. The start solenoid is a round silver thing under the seat, near the battery, that has a big red wire attached to it...running directly from the battery. Touching that red wire to the big black wire that goes to the starter bypasses the solenoid, the starter button, and all the wiring in between. That would quickly tell you if the starter has failed.

Once again, we are WAY past checking for a blown fuse. Are you sure you want to do this? Do you have a friend that you can ask?