Author Topic: CB400f Blowing Main Fuse (Read 10157 times)

FuZZie · « **Reply #25 on:** March 06, 2018, 09:26:01 PM »

Quote

My friend has suggested that I disconnect the solenoid to try and eliminate that. I was planning to try that tomorrow night (need to buy more fuses)

disconnect and bench test it!

follow the +line off the battery in the image I posted, solenoid and starter are unfused and full power on that path. look at the coil wire that switches the solenoid on. Your checking for shorting from the coil to the battery circuit first.

scottly · « **Reply #26 on:** March 06, 2018, 09:30:15 PM »

Quote from: strynboen on March 06, 2018, 11:08:55 AM

that start safty rectifire(diode)..looks like a problem maker..it can make a direkt short..
try to take the power of the diode..and see if the fuses then hold up

The purpose of the diode is to isolate the clutch switch from the neutral indicator light; if it's shorted, the neutral light will illuminate when the clutch is pulled in; it won't blow the main fuse.
Jake, the solid black wires are the switched +12V that feed the starter button/headlight, kill switch, voltage regulator, brake light etc. You are looking for a short from a black wire to ground. Solid green wires on Honda's are ground wires. Since the problem started after pressing the starter button, disconnect any black wires going to the control for a start.

Yamahawk · « **Reply #27 on:** March 07, 2018, 03:58:45 AM »

Quote from: jakec on March 06, 2018, 09:15:22 PM

First time (Saturday) it only blew once the starter button was pressed. But every time since then it has blown as soon as the key is turned to ON. Whether the KILL is in the ON position or the OFF position, the fuse blows as soon as the key is turned to the ON position.

I can turn the key quickly past ON to PARK and the fuse won't have time to blow. But it will get real bent out of shape.

I bypassed the ignition switch tonight and it still blew. If it were a short in the right hand switch, what would that look like?

My friend has suggested that I disconnect the solenoid to try and eliminate that. I was planning to try that tomorrow night (need to buy more fuses).

It is good to support the fuse manufacturer's of the world, but not the best way for you to troubleshoot your problem... why don't you spend $5 on a test light, any automotive store will have one, and clip that between your fuse connections. Or better yet, find a 28 watt bulb with socket, and clip that between your contacts. A GE 1156 bulb would work, and glow brightly when there is a short, and dimly when there isn't If you have spare bike parts laying around, they might be in a turn signal. just wire it (the whole turn signal, lens and all) across the fuse connection. If it only has 1 wire, that is hot, and the stalk is the other connection easily connected to the other side of fuse connector with alligator clip lead... Save your fuses for when it is fixed.
Charlie

calj737 · « **Reply #28 on:** March 07, 2018, 04:13:16 AM »

Quote from: scottly on March 06, 2018, 09:30:15 PM

Jake, the solid black wires are the switched +12V that feed the starter button/headlight, kill switch, voltage regulator, brake light etc. You are looking for a short from a black wire to ground. Solid green wires on Honda's are ground wires. Since the problem started after pressing the starter button, disconnect any black wires going to the control for a start.

^^^^This.

The original source of the BLACK wire that feeds everything is the key switch. Start your inspection there, and work your way towards the handlebar and the VR.

jakec · « **Reply #29 on:** March 07, 2018, 08:50:41 AM »

I have an entire brake light assembly for my CL175 that I could try this with I suppose. I want the light to be dim? And if it's bright, that's the equivalent of blowing the fuse (too much amperage)?

There are 2 black wires coming from the right hand controls, one for the kill switch and one for the starter switch. Since i'm suspecting the starter switch, I should disconnect its black wire and see if the fuse (or light) still blows?

Quote

The original source of the BLACK wire that feeds everything is the key switch. Start your inspection there, and work your way towards the handlebar and the VR.

I already jumped the key switch with no results. VR?

FuZZie · « **Reply #30 on:** March 07, 2018, 12:57:50 PM »

voltage regulator

Keith · « **Reply #31 on:** March 07, 2018, 04:47:40 PM »

At this point, you are only guessing at the problem. Pull the fuse, insert the 12v test light. It will light up, indicating you have power on one side of the circuit, and a short to ground on the other. Look at the wiring diagram, study what is powered up by that fuse. Nothing else matters, only what's on that circuit. Now, start disconnecting one thing at a time until the light goes out...bingo! Should take only a few minutes.

Stev-o · « **Reply #32 on:** March 07, 2018, 05:37:52 PM »

Had a bad feeling about this bike, sorry to here of the issue. Who sells a $4K bike w/o a battery?

Here is the type of test light you need [$6], sold all over...

https://www.amazon.com/Professional-6-12V-Circuit-Tester-Industrial/dp/B003UHNMMS

scottly · « **Reply #33 on:** March 07, 2018, 07:13:17 PM »

Quote from: jakec on March 07, 2018, 08:50:41 AM

There are 2 black wires coming from the right hand controls, one for the kill switch and one for the starter switch. Since i'm suspecting the starter switch, I should disconnect its black wire and see if the fuse (or light) still blows?

The black wire with the white stripe is the output side of the kill switch; if it were shorted, the fuse would only blow, or the test light brightly glow, when the kill switch was set to Run, unless the short is in the control itself. The solid black wire is the input. The black/red wire is the output to the headlight, unless the starter button is pressed, at which time the power is transferred from the headlight to the starter solenoid on the yellow/red wire. Try disconnecting all the wires to the right hand controls and see what happens.
PS, to judge the difference in brightness with a test light, connect the leads directly to the battery; this will be the brightness of a dead short with the test light substituting for the fuse.

jakec · « **Reply #34 on:** March 08, 2018, 09:54:39 AM »

Quote

Had a bad feeling about this bike, sorry to here of the issue. Who sells a $4K bike w/o a battery?

The previous owner definitely had this bike sitting for a long time. Everything single part of the bike is so clean like it's never been outside. Then there are small clues like the petcock, which was really gummed up with varnish. He probably stored it without a battery because he didn't feel like buying a new one. and It did technically come with one... he shipped the battery separately with no acid

Anyways, I was able to isolate the short last night, I disconnected the black wire from the starter button and the fuse stopped popping. Instrument lights come on fine now. Brake light and switches work good.

However the headlight (and everything controlled on the left side) was not lighting up. I'm not sure if the headlight is broken or not, I fiexd the prongs with epoxy, but I was showing 0.00 volts on the headlight dongle with the key on.

I tested the battery terminals and it was only showing 10.38 volts. First charge ever and it had been sitting for about a week so I am charging it now. Last I checked it was showing 14.8 volts. Hoping all the other non working parts (blinkers, horn, headlight) come on with a full battery.

As for the starter switch, I supposed I will get it off and see if I can't rebuild it and find out why it's shorting. Any suggestions?

P.S. dont feel sorry for me, I feel like this is a good way to get acquainted with the new bike. At first I was afraid to touch it (don't feel that way on my other bikes) but that feeling is slowly melting away.

scottly · « **Reply #35 on:** March 08, 2018, 10:11:57 AM »

Quote from: jakec on March 08, 2018, 09:54:39 AM

Anyways, I was able to isolate the short last night, I disconnected the black wire from the starter button and the fuse stopped popping. Instrument lights come on fine now. Brake light and switches work good.

However the headlight (and everything controlled on the left side) was not lighting up.

The black wire supplies power to the headlight, so with it disconnected the headlight won't work.

jakec · « **Reply #36 on:** March 08, 2018, 10:20:23 AM »

Disconnecting the black wire that goes to the right hand control (start button) will stop the headlight from working?? Jeez! Ok looks like I need to figure out why the switch is shorting asap.

scottly · « **Reply #37 on:** March 08, 2018, 10:45:01 AM »

Disconnect the other wires from the control, and plug the black wire in. If the fuse blows, the short is in the control, possibly shorting to the handlebar.

jakec · « **Reply #38 on:** March 09, 2018, 08:33:49 AM »

Haven't had time to work on the bike yet, but I have to remove the wheels tonight so I can take them to the tire place to get my new tires installed. Will have to revisit this on Saturday or Sunday.

Stev-o · « **Reply #39 on:** March 09, 2018, 08:39:25 AM »

Quote from: jakec on March 08, 2018, 09:54:39 AM

Quote
Had a bad feeling about this bike, sorry to here of the issue. Who sells a $4K bike w/o a battery?

P.S. dont feel sorry for me

It's not that I feel sorry for you but I dont like to see buyers taken for a ride.
For what you paid for that bike, it should have been a running, no issue bike.
Dont ever believe a seller's stories!

jakec · « **Reply #40 on:** March 09, 2018, 09:47:52 AM »

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For what you paid for that bike, it should have been a running, no issue bike.

Yeah, luckily it's not costing me any money yet, just time.

jakec · « **Reply #41 on:** March 10, 2018, 08:10:14 PM »

Hey guys finally got to work on the bike today.

Since you guys deserve some pics by now here you go, new side covers:

Anyways the wheels are off for tire replacement right now. I was able to determine that the new battery is acting up and was causing everything to not work. After charging it a second time it's still showing 10.3 volts. I'm charging it again now. Does anyone know what could be causing that? The initial short out? overfilling acid (it's a bit above the lines)?

I put in the battery from my CL 175 in (showing 12.5 volts). Everything works now. I have the right side control opened up and dangling off of the bar and no shorts.

I wrapped the bar in some electrical tape, and then put the controls back on, and it shorted again. So I am guessing it's shorting against the bar. Any ideas other than more electrical tape?

Stev-o · « **Reply #42 on:** March 10, 2018, 08:18:42 PM »

Is the battery new? If yes, could be defective. If no, get a new one, I like AGM, no chance of spilled acid.

BTW - new side overs look great!

Flyin900 · « **Reply #43 on:** March 10, 2018, 08:26:48 PM »

You may have a problem with the switch internals that could be grounding on the handlebars. The kill switch section is high up in the switch and too far away from the bars. So the push button starter part could be grounding out against the bars as its back end where the wires are located would be the closest to short out.
There maybe a short in the wiring that is also causing the issue somewhere close to the area where the wires go down into the cutout for the handlebars. This assumes the wiring is routed down through the handlebars internally and it could be shorted in that area too.

Sounds like you have the area pin pointed better now and just a check of the wiring should reveal the issue. It also sounds like that battery is pooched and could have a short in one of the cells. If you can't get 12.6 V + after charging then something is wrong with the battery.

Side covers look great and did you buy them finished or have them sprayed the Varnish Blue?

jakec · « **Reply #44 on:** March 10, 2018, 08:27:46 PM »

The battery was new, shipped to me with no acid and I filled it. I probably overfilled it a bit as all the cells are a bit over the top line. Is that bad?

Edit: yeah a friend of mine suggested I shorted a cell the first time the bike blew the #$%* out of the main fuse. I'm 99% sure that the starter push switch is the short and it is against the bar. When the control is on the bar and the black wire to the switch is disconnected, no short. When it's all hooked up but dangling, no short.

I had a problem like this where the horn was shorting on the bar of my CL and the horn would honk constantly when the key was on. I just wrapped the bar in tape and that fixed the problem.

Flyin900 · « **Reply #45 on:** March 10, 2018, 08:31:35 PM »

No not an issue with a slight overfill, yet it could have been booted around in transit and a cell or section is no good internally even though it is brand new.

jakec · « **Reply #46 on:** March 10, 2018, 08:48:38 PM »

Hm. Ok. So I am charging it now. Do you think that if it's not charging above 10.3 now it never will? The battery was included in the sale so at this point I am only in it for $5 in acid. I can buy a new battery if needed.

scottly · « **Reply #47 on:** March 10, 2018, 08:54:15 PM »

Is 10.3 the voltage at the battery while it's on the charger? What type of charger are you using? Typical "tender" type chargers are limited in current output, and may take a very long time to bring a discharged battery's voltage up to 14.5V.

jakec · « **Reply #48 on:** March 10, 2018, 08:58:51 PM »

Terminals show 14.6 when it's plugged into the tender. When its unplugged it shows 10.3

scottly · « **Reply #49 on:** March 10, 2018, 09:08:57 PM »

Sounds like the battery is toast.

BTW, blowing the fuse shouldn't have killed a cell; it's job is to sacrifice it's life to protect the battery and wiring by blowing at a safe level of current.

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Author Topic: CB400f Blowing Main Fuse (Read 10157 times)