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Discussion Starter #1
Hi all. Last weekend one of my friends moved out and realized that in the back of his garage he had two 1980s era suzuki gs450's. One is all original, the other is a rolling frame with mostly updated electronics (indeed some sketchy wiring, ill add pictures when I can). He gave them both to me for free, so while I have little to no experience working on motorcycles I do own and have done countless repairs on my 1984 seadoo sp jetski so I have some mechanical experience. I know jetskis and bikes are VERY different, so that why im here. I was told the engine on the complete bike ran at some point, but that's all the info I was given. I started to dig into the bike, and got all electrical to work but the start switch located in the cluster on the handlebars. I can get the engine to turn over by jumping the starter solenoid, but nothing from the switch. I tested the start switch and it seems to have resistance and not when pressed and depressed respectively. II tested it for spark while jumping the solenoid, but got nothing. I got access to the original wiring diagram and I have a repair manual in the mail as I type... I have a multimeter and a lot of time on my hands. I got the carbs cleaned and double checked that the engine was free and would turn over okay. All i need is spark, and im trying to start with the start switch as that is early not working. Is there another way to test the start switch (not the stop/run switch)? I read something about a kickstand switch too, but don't think there is one on my bike. Anyways, Im very confused but still have a boatload of hope because this project has cost me a bottle or carb cleaner and a few hours. Also, it was in neutral when I was doing the tests. Any tips on wiring or help in general would be super helpful. I also tested the ignition coils and got good readings on primary side, but got zero resistance on secondary side. I may be testing it wrong, so I wanted to come on here first so I don't waste money on parts I do not need. Thanks.
 

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Cool!
Step one obtain an OEM service manual for your bike, hopefully free on the internet. Then go crazy with the meter testing using the manual as a guide for starters, because nothing is better then that.
 

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"got good readings on primary side, but got zero resistance on secondary side"
That don't sound right, might want to check your meter settings or something.
 

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Discussion Starter #5
"got good readings on primary side, but got zero resistance on secondary side"
That don't sound right, might want to check your meter settings or something.
Other forums say that for testing ignition coils, set the ohms to 200 for primary, 20k for secondary. Is that not correct? will do a little more digging this afternoon.
 

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Pretty sure spark side will only have a couple of ohms resistance.
One other theory is that you can set it all up and throw 12volts through it and watch for a spark, taking obvious precautions not to jolt yourself too badly :|
 

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Discussion Starter #7
update- Re checked the coils according to the repair manual and both coils are intact and in good shape. Used the multimeter and tested both the kill switch and start switch (both of which operate correctly). I then tested every ground I could access without pulling the motor. Tested the fuse the bike has and no issue there. I'm stumped. I don't get why every other electrical aspect of the bike functions but the start button. Could it be the starter solenoid? I had a bad starter solenoid on my jetski but I don't get the click of doom when I hit start on the bike like I did in that case. When the start button is pressed, the bike does not react at all. No clicks, no nothing. All lights and horn work normal. The oil pressure light is on, not sure if that a problem with having the engine turn over. The motor will turn over if i cross the poles on the starer solenoid.
 

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Jump start it with a car battery, put the ground cable straight to the motor, see if that suddenly works ;)

It could be the solenoid relay or just a bad connection to it but the meter should tell you that too.
 

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Are you pulling the clutch in? That bike should have a clutch safety switch
 

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Discussion Starter #11
Bad fuse/socket? Continuity from switch to solenoid?
Tested the fuse and fuse holder both okay, will look into continuity from switch to solenoid tmrw. To test that I just trace the power and signal wires from switch to solenoid and test the continuity from their respective poles?
 

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Tested the fuse and fuse holder both okay, will look into continuity from switch to solenoid tmrw. To test that I just trace the power and signal wires from switch to solenoid and test the continuity from their respective poles?
I would check for voltage. Are you getting power through the system, where does it end in the trace?
 

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High resistance on a wire segment that should have zero resistance will similarly result in low voltage readings over that same connection. So yes you are looking for either measurable resistance or lower voltage as you test each circuit and that signifies a problem.
 

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Again, no mention of the clutch lever. Every GS of that vintage has a clutch safety switch in the start button circuit.
 
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Discussion Starter #15
Again, no mention of the clutch lever. Every GS of that vintage has a clutch safety switch in the start button circuit.
Spent a couple more hours today with the wiring diagram and multi meter tracing wires back through the harness. All in all, I know for sure that the start button, kill switch, clutch lever switch, and starter solenoid work. I also tested every ground I could find by putting one end of the multi meter on the positive of the battery and the other lead on the ground. It baffles me that voltage goes to every other part of the bike (including the solenoid, i tested the poles and here was 12.9v). I'm an 18 year old still in high school so while my background knowledge on mechanics and bikes is limited, due to corona virus i have ample time on my hands to trouble shoot. Seems like i'm running in circles or haven't checked something the correct way. One thing I would note is that the horn dose not function either and there is no voltage at the terminals. I also confirmed the starter motor is intact as it turns the motor over via crossing the terminals on the solenoid with a screwdriver. Help appreciated as always. I know I sound like I don't really know what i'm doing... that is mostly correct. I'm using this experience to learn and hopefully will end up with a running bike in the end.
 

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Discussion Starter #17
Just did some more testing after looking through the forums. Found a major issue/short. When they key is in the off position, im getting right around 13DCV at the starter button. As soon as I turn the switch from off to on, the voltage drops down from 13v to .18v. Im getting this low voltage reading at the horn and at the switch. I traced the wire all the way back to the Ti ignitor but found no voltage raise or frayed/cut wires. It got dark before I could trace the rest of the wires. Could the short be in the stator/ generator?
 

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The stator (generator) won’t come into play until the engine is running.
 

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Discussion Starter #20
Your getting 13vdc at the starter switch while the key is off?
That is correct. I also got the same reading further down on the wire where it connects to the tr Igniter and at the horn connection. All of these readings drop to about .17vdc when the key is turned to the on position.
 
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