Author Topic: What the **** Happened to my bike? (Read 3471 times)

haloskycrash · « **on:** March 05, 2009, 03:42:11 PM »

I have a 1975 CB 750F. The bike runs fine, new battery. Today, I stop in traffic and it just dies. I tried to electric restart and nothing worked. I rolled it over to this shop a block away and we tried to see if it was the battery. Battery is fine, no blown fuses. When I turn the key to on, nothing lights up. Oh, and I can't kick start or bump start it. What is it then? I don't think it's the spark plugs cause they are 3 months old and the bike ran fine till today.

Duke McDukiedook · « **Reply #1 on:** March 05, 2009, 03:47:12 PM »

Bad plug wires?

haloskycrash · « **Reply #2 on:** March 05, 2009, 03:53:45 PM »

how about something with the ignition being out. It's like there is no key in the bike if it doesn't work and it won't turn over, right?

Really? · « **Reply #3 on:** March 05, 2009, 03:54:24 PM »

A shot in the dark here - ignition switch, engine stop switch is bad or last but not least...the engine stop switch in the off position.

Gregorymoto · « **Reply #4 on:** March 05, 2009, 03:55:26 PM »

Get a continuity tester. See if you are getting getting spark first, pull plug turn over motor bla bla bla, if no check power to your Coil, your Points, and your ignition.
Good luck man.

andy750 · « **Reply #5 on:** March 05, 2009, 03:56:51 PM »

Looks like the ignition switch is toast. Been there and done that more than once.

Good luck sorting it out.

cheers
Andy

sangyo soichiro · « **Reply #6 on:** March 05, 2009, 03:59:51 PM »

Some things to check:

1. Check to see if the ground is loose (or broke) where it connects to the frame (this is my guess of what's wrong).

2. Make sure the wires to the battery are not loose.

3. Check to see if the wire connector plug thingy that goes to the key switch came loose.

4. Make sure the surfaces between the battery and the wires are clean (perhaps sand it a bit).

Try those and let us know.

Good luck.

sangyo soichiro · « **Reply #7 on:** March 05, 2009, 04:00:56 PM »

Quote from: GigaWhiskey on March 05, 2009, 03:54:24 PM

A shot in the dark here - ignition switch, engine stop switch is bad or last but not least...the engine stop switch in the off position.

Oooh yeah... you didn't accidentally bump the kill switch did you?

Edit: I take this one back. Doesn't sound like this is the culprit. If this were the case, your starter would work and the lights would light... it just wouldn't start (been there, done that).

haloskycrash · « **Reply #8 on:** March 05, 2009, 04:01:22 PM »

I don't know ignition switches, they tricky to put together? Well, I should check if it's even toasted.

haloskycrash · « **Reply #9 on:** March 05, 2009, 04:03:17 PM »

Where is the ground you are asking to check? I can run downstairs and check that.

sangyo soichiro · « **Reply #10 on:** March 05, 2009, 04:08:14 PM »

Quote from: haloskycrash on March 05, 2009, 04:03:17 PM

Where is the ground you are asking to check? I can run downstairs and check that.

I had two wires that connected to the frame. They are on the left (port) side. The main one comes directly from the battery, is a little over a foot long, and connects to one of the engine mounting rods/bolts (just above the transmission). The other is a smaller wire that connects to a bolt near the seat lock (you may need to take off the side cover (be careful not to crack the side cover...)).

haloskycrash · « **Reply #11 on:** March 05, 2009, 04:15:39 PM »

I will look for the ground wires. By the way, that's a dope cafe you got going there. Mine is a cafe too, more ratty...

scondon · « **Reply #12 on:** March 05, 2009, 04:28:15 PM »

Don't forget that blown fuses can "look" good even when they're bad. If you replaced fuses with good ones already then ignore this bit

sangyo soichiro · « **Reply #13 on:** March 05, 2009, 04:33:10 PM »

Thank you for the complement. Yours looks pretty sweet too.

Back to the problem...

Here's what we know (correct me if I get anything wrong):
-It was running fine.
-Then, out of the blue, it dies in the middle of the street.
-Turning the key doesn't do anything, you say "nothing lights up."

Here's what little I know (and will take the liberty of speculating a bit):
If nothing lights up, then it smells like it's an electrical problem.

If it was running fine, and all of a sudden doesn't run, then the problem is such that it occurs in a very rapid fashion. Keep this in mind. A perfect example is a wire that all of a sudden breaks, or a wire that has worked itself juuuust loose enough to prevent current from flowing or a blown fuse.

I feel pretty confident that it's electrical though.

And I agree with scondon, it can't hurt to check the fuses again. I usually start with the easiest stuff first.

GammaFlat · « **Reply #14 on:** March 05, 2009, 04:36:29 PM »

Quote from: scondon on March 05, 2009, 04:28:15 PM

Don't forget that blown fuses can "look" good even when they're bad. If you replaced fuses with good ones already then ignore this bit

This is my bet (are we betting?) ... and don't ask me how I know

Check the bottom fuse

haloskycrash · « **Reply #15 on:** March 05, 2009, 04:38:34 PM »

Yeah, I should pull all the fuses and buy them. Don't worry, I will take a pic so I won't more of a problem

haloskycrash · « **Reply #16 on:** March 05, 2009, 05:23:07 PM »

Yes, it was only a blown fuse. Just going to get the fuse made me pissed to be driving a car. I was sitting in traffic just staring between the two lanes thinking I could be there and back by now.

GammaFlat · « **Reply #17 on:** March 05, 2009, 07:02:01 PM »

Man - don't feel bad. Just be glad it was simple. Most unknown problems end up simpler than expected.

Enjoy your bike.

On another note.... fuses can go bad for a couple reasons. One of them is just plain heat cycling and age. A contributor is when you have "losses" at most or all connections. I'm in the middle of replacing my rectifier, voltage regulator, fuse holder and 3 connectors. I hope and expect this to improve the electrical system enough so that my charging system works like new and my voltage is "up".

I'll be posting what I've done soon (I've leaked some of it out already).

You're in the right place. There's lots of great folks here to help you. I've been inspired and helped here tons.

Regards,

John

stresssolutions · « **Reply #18 on:** March 05, 2009, 07:21:48 PM »

Does not boost my confidence in the shop a block away, though.

I had the same exp, once. fuse went bad but looked good. I now carry spares.

Spanner 1 · « **Reply #19 on:** March 05, 2009, 07:27:45 PM »

Stress, how'dya like that 'A' ?

rachet · « **Reply #20 on:** March 05, 2009, 08:07:01 PM »

I was just getting to speed (about 60mph) when my bike died and left me on the side of the road. 2 hours by the time Triple A showed up and towed me home. I checked the fuses and they all looked fine. It wasn't until I went to remove them that I found one of them had blown just inside the silver cap. Just looking at it, you would never know it was bad.

What really drives me nuts is that I had spare fuses inside the cover for the fuse block. Could of saved a lot of time if I had just physically removed the fuses, instead of just looking at them.

stresssolutions · « **Reply #21 on:** March 06, 2009, 03:54:00 AM »

Quote from: Spanner 1 on March 05, 2009, 07:27:45 PM

Stress, how'dya like that 'A' ?

Except for not being able to buy throttle cables "off the shelf", I like it fine. OH, and the no engine braking is a little different. Shouldn't phrase it that way, because this is my first bike, have only ridden one other, a 77GL1000, one time. But I can see where engine braking would be very nice in the hilly twisty part of my riding. For going across town, it is awesome, at least until it warms up to the point of having a very fast idle at stops.

Really? · « **Reply #22 on:** March 06, 2009, 05:49:23 AM »

Had something similar happen on my VR now that I think of it. Middle of horrid traffic on 635 close to Garland, Texas on my way to a weekend bike rally it stops. It was fracking hot that late afternoon too.

One of the fuse holders had broken slightly so it was loose enough where it was not making contact. It was hard to see in all that traffic Chaos. 'Specially with people driving in the emergency lane like it was a normal lane. Pulled the foil out of my smokes and wrapped it around the fuse. I continued on to Athens, Texas and prolly road another 12-14 hours that weekend.

I still need to fix that, it still has the foil there.

Gregorymoto · « **Reply #23 on:** March 06, 2009, 06:13:37 AM »

If it makes you feel better i once rebuilt a set of carbs on a kaw Z1 when i went to put them back on i found that the issue was that i was out of gas.

sangyo soichiro · « **Reply #24 on:** March 06, 2009, 09:15:21 AM »

Quote from: stresssolutions on March 05, 2009, 07:21:48 PM

Does not boost my confidence in the shop a block away, though.

I had the same exp, once. fuse went bad but looked good. I now carry spares.

I think that's the lesson... carry spares! I've totally neglected this myself. I better get some too.

And yes... about the garage a block away; for cryin' out loud, they do this stuff for a living! And they didn't at least have a fuse you could try? Or a continuity tester to check the fuses? Too many 'experts' aren't any good at what they do....

News:

Author Topic: What the **** Happened to my bike? (Read 3471 times)

haloskycrash

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