Author Topic: cb750a alternator. (Read 23827 times)

TwoTired · « **Reply #50 on:** December 09, 2010, 01:40:57 PM »

Clean everything electrical with Denatured or isopropyl alcohol.

Take your time.

The bullet connector socket can be squeezed to regain retentive action.

The wrapping can be replaced with electrical tape.

If you still think things need replacement, then go to www.vintageconnections.com.

Learn to solder. And use shrink tube or liquid vinyl to cover the soldered wire spliced into place.

Cheers,

andy750 · « **Reply #51 on:** December 09, 2010, 01:47:37 PM »

Quote from: maliveline on December 09, 2010, 11:46:05 AM

Ok I got the shifter cover off. I started looking around in there and guess what. One of the 2 wires coming from my field coil was disconnected....

the only problem is all my connectors are pretty oily and nasty and the plastic wrap around the connectors is totally degrading and everything is very loose.

Also I virtually have no slack at all on the wires that are deep inside the shifter case. I dont even know where to begin to go about fixing this problem.

Congratulations you have found the potential source of your recharging problem! Follow TTs advice and get some new connectors and dont cut too much off the add the new connectors. Even better idea is to take a photo if you can...

this was what I found on my K2 - the interconnecting wires between the alternator and the harness had a frayed green wire.

shifter cover off:

frayed wire

Good luck with it!

Andy

MCRider · « **Reply #52 on:** December 09, 2010, 03:26:43 PM »

Andy, not to hijack the thread, but I guess I am, but it sounds like its winding down... What do you think caused your green wire to get frayed. Was a PO involved, or a misstep in routing it?

andy750 · « **Reply #53 on:** December 09, 2010, 04:05:16 PM »

Quote from: MCRider on December 09, 2010, 03:26:43 PM

Andy, not to hijack the thread, but I guess I am, but it sounds like its winding down... What do you think caused your green wire to get frayed. Was a PO involved, or a misstep in routing it?

Ok not to hijack the thread but....i think it was just the fact it was 38 years old and 55,000 miles later...engine had never been touched until I started into it...just wear really...thats what i am going for at least...may have got caught on something but hard to see what as its under the gear cover...maybe when installed the chrome alternator cover something got pinched? Maybe when removing/reinstalling/removing/reinstalling the engine?

I mention it here only for the general info - something to check in addition to alt, reg, and rectifier.

cheers
Andy

MCRider · « **Reply #54 on:** December 09, 2010, 04:10:16 PM »

Quote from: andy750 on December 09, 2010, 04:05:16 PM

Quote from: MCRider on December 09, 2010, 03:26:43 PM
Andy, not to hijack the thread, but I guess I am, but it sounds like its winding down... What do you think caused your green wire to get frayed. Was a PO involved, or a misstep in routing it?

Ok not to hijack the thread but....i think it was just the fact it was 38 years old and 55,000 miles later...engine had never been touched until I started into it...just wear really...thats what i am going for at least...may have got caught on something but hard to see what as its under the gear cover...maybe when installed the chrome alternator cover something got pinched? Maybe when removing/reinstalling/removing/reinstalling the engine?

I mention it here only for the general info - something to check in addition to alt, reg, and rectifier.

cheers
Andy

Interesting, goes to show...s--- happens.

maliveline · « **Reply #55 on:** December 09, 2010, 11:26:12 PM »

I kinda want to pull out the wire harness that comes out of the top of the shifter case. however there are 3 yellow wires 1 green, 1 white, and 1 black wire.

I know which ones are coming from the alternator but i have no idea where the black wire is coming from....

I want to pull out that harness so I can try to clean it up and possibly soldering on some extensions so I can have a little more slack inside where it hooks up to my alternator.

so basically my question is... If I try to pull out that wire harness whats the deal with the black wire? can I just cut that damm thing off.

andy750 · « **Reply #56 on:** December 10, 2010, 04:39:26 AM »

Do yourself a favour and go here to the SOHC website and look at the CB750A manual - Electrical section - C14 - on page 14.5 there is a very nice diagram showing you the electrical circuit for the alternator, and good info with detailed pictures of how to check your alt, regulator and rectifier. With this info you should be all set:

http://www.sohc4.net/index.php/archives/41

good luck
Andy

Spanner 1 · « **Reply #57 on:** December 10, 2010, 09:16:39 AM »

Could the 'black' wire you describe actually be purple, which is to the oil pressure switch ? You can cut it once you reconnect it by some means, but do need to keep it connected when your done with new connections.............

maliveline · « **Reply #58 on:** December 10, 2010, 09:47:23 AM »

oh ya i guess it is purple

maliveline · « **Reply #59 on:** December 10, 2010, 01:46:09 PM »

I ended up just yanking on the wires to give myself some more slack with a pair of needle nose pliers. It worked pretty good for the most part. Then I started cleaning off
all the old wrapping off the bullet connectors because I decided to use some shrink tubing. I had just about everything wired up and on the last wire I broke a female connector off the bullet connector. So I went to the electric store and bought some new connector and jimmy rigged it and it worked pretty good for the most part.

Getting the shifter cover back on was another story. All the wires from my fresh wiring job were in the way. I kept pushing on them to try to get the damm shifter cover back on. Some of the wires that came from the stator had some of the wire coating crack but I just left it because I was sick of this job and i think it will be ok.

I got the shifter cover back on and now im just waiting for my gasket to dry so i can fill everything up with oil and start my bike and run some more tests. hopefully everything works now.

TwoTired · « **Reply #60 on:** December 10, 2010, 02:29:20 PM »

Skinning off the wire insulation is rather a bad idea. This can lead to blown fuses, or if the yellow wires were skinned, inadequate charging. They are insulated for a very good reason, part of which is to keep the machine reliable.

It was discouraging to see this:

Quote

Some of the wires that came from the stator had some of the wire coating crack but I just left it because I was sick of this job and i think it will be ok.

This reads like you are admitting to shoddy work. Beware the "benefits" of this. Sometimes doing things right takes patience and the learning experience takes diligence. "Shortcuts" are for the experienced who can apply them when appropriate.

I do wish you well. But one of the "jobs" of insulation is to shield the copper wire from corroding. Corrosion will, at some point, make a part in the wire and stop electrical flow. The cracked insulation can be effectively closed when treated with "Liquid Vinyl" found at a Hardware store's electrical section.

FYI

Cheers,

maliveline · « **Reply #61 on:** December 10, 2010, 04:37:24 PM »

ya I asked for liquid vinyl at radioshack the other day and they didn't have it. If worse comes to worse and it stops working I will probably just tear they thing apart and put some liquid vinyl on the cracks in the insulation.

MoMo · « **Reply #62 on:** December 10, 2010, 04:46:07 PM »

Home Depot sells liquid electrical tape. Might work for you.. Larry

maliveline · « **Reply #63 on:** December 10, 2010, 07:39:22 PM »

by the way twotired i forgot to mention. your new avatar isn't any less distracting than your old one.

maliveline · « **Reply #64 on:** December 11, 2010, 09:13:05 AM »

Hey my bike is working!!!

I just wanted to thank you guys for all your help. I am a very impatient person so if I seemed demanding I apologize.

If it makes you feel any better I wasted 40 bucks on that half assed mechanic that did next to nothing for me.

There is one more problem though. Its suppose to rain 2+ inches today here in oregon and I can't go for a ride:(

maliveline · « **Reply #65 on:** December 11, 2010, 01:32:25 PM »

actually crap my head light is blinking when i rev the engine to high rpms. Is this normal?

Spanner 1 · « **Reply #66 on:** December 11, 2010, 02:42:36 PM »

Hope your not impatient on the road, bro

..... take your bike for a nice ride and give the battery time to charge, bet that'll fix it

... it might take 20 or 30 miles.

MoMo · « **Reply #67 on:** December 11, 2010, 04:04:05 PM »

Quote from: maliveline on December 11, 2010, 01:32:25 PM

actually crap my head light is blinking when i rev the engine to high rpms. Is this normal?

no, does it do it with both high and low? If so, probably a loose or corroded green ground. Could even be a bad filament. Larry

TwoTired · « **Reply #68 on:** December 11, 2010, 04:17:41 PM »

Quote from: maliveline on December 11, 2010, 01:32:25 PM

actually crap my head light is blinking when i rev the engine to high rpms. Is this normal?

Heck no.

Exercise your H/L switch so the internal contacts will clean off. Otherwise you have another loose connector, or a bad headlight filament.

Um, Blinking or pulsing?

maliveline · « **Reply #69 on:** December 11, 2010, 05:01:58 PM »

um i would say its more of a pulsing, and i dont have a head light switch. my head lights are always on on that bike as long as the key is turned on

MoMo · « **Reply #70 on:** December 11, 2010, 05:11:27 PM »

I think TwoTired meant high low. Does it do it on both high and low? Larry

TwoTired · « **Reply #71 on:** December 11, 2010, 05:19:14 PM »

It doesn't say H/L on the bar control? You have auto dim headlights?

I would check the voltage at the battery while the headlight is pulsing.

However, if the rest of the bike's electrical wiring is in similar condition to what you described for the alternator, you may need to clean clean all the connectors.

maliveline · « **Reply #72 on:** December 11, 2010, 05:24:08 PM »

oh when you said H/L I thought you were abbreviating head light lol.

actually I switched it to High beams and revved it up and it wasn't really doing it and then i switched back between H and L and kept revving and it fixed it

thanks again..

maliveline · « **Reply #73 on:** December 11, 2010, 11:22:44 PM »

Man I put that shifter cover back on and my shifter pedal seems like its a lot more difficult to shift in to gear now. down shifting into neutral from drive isn't so bad but lifting the pedal up from neutral into drive and then into over drive is a pain in the butt now.

andy750 · « **Reply #74 on:** December 12, 2010, 05:01:34 AM »

Quote from: maliveline on December 11, 2010, 11:22:44 PM

Man I put that shifter cover back on and my shifter pedal seems like its a lot more difficult to shift in to gear now. down shifting into neutral from drive isn't so bad but lifting the pedal up from neutral into drive and then into over drive is a pain in the butt now.

I thought you had an automatic?

News:

Author Topic: cb750a alternator. (Read 23827 times)