Author Topic: electrical problems! (Read 2546 times)

mr_jason · « **on:** November 13, 2005, 02:51:21 PM »

last night i rode my 78 cb750 to work, no problems at all. i just bought it a few weeks ago and it runs great, etc.

so after work i go to start her up, and i turn on the ignition and nothing, no lights, nada. i try to kick start, nothing. it's like the key isn't turned on.

any advice on where to start? does this sound like it's just a short and i'm gonna have to just find it?

also, it rained here for 2 days and unfortunately i had to leave the bike out in the rain, do you think this could have done something? this was the first ride after the rain.

thanks guys,

jason

Sam Green Racing · « **Reply #1 on:** November 13, 2005, 03:11:05 PM »

Has it got a kill switch on the bars that you forgot about.......just a thought

Sam.

TwoTired · « **Reply #2 on:** November 13, 2005, 03:20:51 PM »

Check main fuse.
Check ignition switch (wiggle the the key).
Check connector on back of switch.

Oh yes, Check battery voltage.

seaweb11 · « **Reply #3 on:** November 13, 2005, 04:36:15 PM »

Last winter before I started my restoration, the bike worked great/. After Complete disassembly and reassembly and when I was all done and turned the key NOTHING. 3 months work and a liitle depressed.........someone here said to replace the switch.

Turns out these old ignition switches can go for no reason at all. Put in a new one and away I went.

Good luck

Mark M · « **Reply #4 on:** November 14, 2005, 03:42:40 AM »

When you check the fuses and ignition switch connections make sure you also give all the connectors a good clean, I like to rub them down with a very fine wet and dry paper untill they shine like new. They tend to build up an oxidised coating which may look ok but wont pass a current.

Steve F · « **Reply #5 on:** November 14, 2005, 03:55:28 AM »

Had the same thing happen to me. Turned out to be the key switch. What happened was there was enough resistance in the contacts inside the switch to make them hot, and they melted into the plastic where the contacts were held. Turned off the switch, they cooled down and then were melted into the plastic far enough to no longer make contact. No power to anything. I was able to move the main fuse at a diagonal to another position, and then I had power to the ignition, and had to use the kickstarter to get the engine going. No headlight or signals, but was able to get home. Sounds like you're going to have to replace the key switch too.

mr_jason · « **Reply #6 on:** November 14, 2005, 04:08:26 AM »

hey thanks guys!

i'll look into all this and see what i can do. think it'll be hard to find a new ignition switch? is this something i might be able to find locally? i'm in los angeles.

jason

MetalHead550 · « **Reply #7 on:** November 14, 2005, 12:49:04 PM »

Make sure its not just a bad battery before you start tearing into stuff! Check that the ground for the battery is good too.

mr_jason · « **Reply #8 on:** November 14, 2005, 03:02:19 PM »

if it was just the battery, shouldn't it kick start?

apormarkos · « **Reply #9 on:** November 14, 2005, 03:14:55 PM »

kickstarting with a totally dead battery is either impossible, or next to it. i don't think the alternator can generate enough (or any?) juice to create a spark at the low rpm you get with the kicker. after a few kicks, i usually ended up pulling my other bike over and jumping the thing- and then getting a new battery for the dead bike.
apor

mr_jason · « **Reply #10 on:** November 14, 2005, 03:47:43 PM »

cool, i'll look into that too.

j

TwoTired · « **Reply #11 on:** November 14, 2005, 04:36:50 PM »

Quote from: mr_jason on November 14, 2005, 03:02:19 PM

if it was just the battery, shouldn't it kick start?

No.
You need voltage to power the ignition coils.
The alternator needs a magnetic field to produce power. And, the field coil is powered from the battery.
Dead battery, no electrical power, no spark, no start.

seaweb11 · « **Reply #12 on:** November 14, 2005, 11:40:09 PM »

" think it'll be hard to find a new ignition switch? "

I got mine from the local dealership. Next day!

mr_jason · « **Reply #13 on:** November 15, 2005, 03:46:34 AM »

great, that's a bunch guys. i'm getting a new battery today and if that doesn't fix it i'm gonna install a new ignition switch and go from there. i'm glad there's a forum like this to help me out.

jason

ofreen · « **Reply #14 on:** November 15, 2005, 04:20:43 AM »

Quote from: mr_jason on November 14, 2005, 03:02:19 PM

if it was just the battery, shouldn't it kick start?

Here is the link to a post I made recently. It may be possible to kickstart the bike if the problem is the battery and if you disconnect the headlight.

http://www.sohc4.us/forums/index.php?topic=5090.msg40043#msg40043

Greg
'75 CB750F

Paul · « **Reply #15 on:** November 15, 2005, 08:40:50 AM »

Tip of the day:
It sounds like it may be worth your while getting a little volt tester.
These are like a pen with a wire comming out the back and a crocodile clip to attach to the frame or Negative.
The tip of the pen has a point that will pierce the wire insulation without doing any damage, and a bulb will light in the centre when there is power. $Peanuts
Hope I'm not being condescending.

dusterdude · « **Reply #16 on:** November 15, 2005, 09:00:19 AM »

crocodile clip,aint ever heerd of that one.

Bob Wessner · « **Reply #17 on:** November 15, 2005, 09:28:32 AM »

Probably what we call an alligator clip here. Might be one for our translation table.

dusterdude · « **Reply #18 on:** November 15, 2005, 10:59:21 AM »

i would say so

Paul · « **Reply #19 on:** November 16, 2005, 01:03:37 AM »

No..
The alligator clip is different as you can see by the two examples. The aligator clip faces upwards.

dusterdude · « **Reply #20 on:** November 16, 2005, 05:29:51 AM »

ok paul im with ya,i just have never heard that description before.

lifeofthe88@yahoo. · « **Reply #21 on:** November 16, 2005, 06:36:54 PM »

everybody needs a voltage tester/multimeter or whatever cause it sucks spending money on stuff that doesnt fix the problem.i learned my lesson on my old project bike.unfortunatly im done with that bke and gonna work on a vintage yamaha

News:

Author Topic: electrical problems! (Read 2546 times)

mr_jason

mr_jason

MetalHead550

mr_jason

apormarkos

mr_jason

mr_jason

lifeofthe88@yahoo.