Author Topic: 1972 cb500 - Charging system issue  (Read 19960 times)

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Offline zenocchio

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1972 cb500 - Charging system issue
« on: January 20, 2013, 05:51:54 PM »
I just got a new to me bike, a 1972 cb500 four.
The bike is a bit of a mix, and it came almost in pieces.
The engine has been rebuilt by the previous owner, as well as the carburators, and now i am trying to figure out how to put together this bike.
My first nightmare is the electrical system.
I have a box full of wires and it seems that I cant put them together.
I am using tthe wiring diagram attached to start the bike, will this diagram works or can I simplified it even more?
thanks
« Last Edit: July 09, 2013, 10:09:32 AM by zenocchio »

Offline zenocchio

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Re: New Project 1972 cb500
« Reply #1 on: January 21, 2013, 09:20:17 AM »
Does someone can direct me to a build thread that can help me sorting out my issues?
Thank you!

Offline Mo

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Re: New Project 1972 cb500
« Reply #2 on: January 21, 2013, 12:35:38 PM »
Not sure about a build thread, but this may help you figure out what get connected to where.

http://oldmanhonda.com/MC/wiring500.html

Offline zenocchio

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Re: New Project 1972 cb500
« Reply #3 on: January 21, 2013, 02:36:17 PM »
Not sure about a build thread, but this may help you figure out what get connected to where.

//oldmanhonda.com/MC/wiring500

Thanks, that is actually what I am using to go over it.
Is there a way to start the bike without a battery?

Offline seanbarney41

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Re: New Project 1972 cb500
« Reply #4 on: January 21, 2013, 09:01:10 PM »
you can jumper in any battery, car battery(don't have the engine running!), just need 12 volts
If it works good, it looks good...

Offline hondamatteo

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Re: New Project 1972 cb500
« Reply #5 on: January 21, 2013, 10:55:58 PM »
Haha no way! I was on my way to check out this bike and probably buy it when the PO called and said he just sold it (to you I suppose)! Looks like a fun project, enjoy! Let me know if I can help you out.

-Matteo
'74 CB350F

Offline zenocchio

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Re: New Project 1972 cb500
« Reply #6 on: January 21, 2013, 11:34:34 PM »
Haha no way! I was on my way to check out this bike and probably buy it when the PO called and said he just sold it (to you I suppose)! Looks like a fun project, enjoy! Let me know if I can help you out.

-Matteo

Hei matteo, it is definitely a fun and long term project! I still have to hear the engine running, hopefully there will be no surprise.
I definitely would like to have a chat, as I am new in the bike world

Offline rb550four

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Re: New Project 1972 cb500
« Reply #7 on: January 22, 2013, 08:03:05 AM »
So, are you planning to go with a stock wiring harness? All your tabs have been cut and  there is no battery box.
  Are you looking to rewire  to a cafe style ? That 's different. It's been done here a hundred different ways by as many people.
   Have some idea of what you are keeping and what you want to delete ,if anything. bare min.....
http://www.hondachopper.com/garage/simple_wiring_diagram/simple_wiring_diagram.html
A few Honda 500's, a few Honda 550's, a few Honda 650's, '72 cb 450, a couple 500/550/650 hybrids, and 2001 750. 
  550 Snowbike -Somebody had to do it.
  http://forums.sohc4.net/index.php/topic,101678.0.html             
http://forums.sohc4.net/index.php/topic,137317.msg1550907.html#msg1550907

Offline Scott S

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Re: New Project 1972 cb500
« Reply #8 on: January 22, 2013, 12:54:30 PM »
 Cool looking bike. I dig the exhaust and engine detailing. Be prepared to spend a little time jetting it with those stacks (and to take a little flak about running them).
'71 CB500 K0
'17 Triumph Street Scrambler
'81 Yamaha XS650

Offline Mo

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Re: New Project 1972 cb500
« Reply #9 on: January 22, 2013, 08:20:50 PM »
david silver spare uk has a replica wiring harness for your bike if you need. I think its $130 plus shipping, but might be easier than trying to source one that has issues.

Offline zenocchio

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Re: New Project 1972 cb500
« Reply #10 on: January 22, 2013, 08:26:05 PM »
Thanks guys,
I spent the past two days studying the wiring diagram, and found that there are a lot of mistakes or differences between the one available online.
I am rebuilding the main harness, I got all together, and I would like to run most of the wires too. I will relocate the electronics under the seat, and the battery will go in the back on a plate that has been welded on the frame by the PO. The headlight has HI/Low switch on it, so I will just run a start/horn/blinkers on my left and a killswitch on the right.
I am not sure if I can fit the instrumentation as the light switches will be covered, do you have any suggestion?
I dont have the key for the main switch nor for the fork lock, do you think I can find someone that will make it or should I just get a replacement part?
Slowly I will look into a seat, I have the double bucket seat that the bike came with, and I am thinking about using the seat pan to make a new one. Do you have any suggestion on a seat for my project?
here some pictures:

Offline zenocchio

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Re: New Project 1972 cb500
« Reply #11 on: January 22, 2013, 08:30:01 PM »
pictures attached

Offline Bankerdanny

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Re: New Project 1972 cb500
« Reply #12 on: January 23, 2013, 06:20:30 AM »
Fortunately these bikes have very basic electrical systems. Be patient and I have no doubt that you can sort it out.
"The problem with quotes on the Internet is that you never know if they're true" - Abraham Lincoln

Current: '76 CB750F. Previous:  '75 CB550F, 2007 Yamaha Vino 125 Scooter, '75 Harley FXE Superglide, '77 GL1000, '77 CB550k, '68 Suzuki K10 80, '68 Yamaha YR2, '69 BMW R69S, '71 Honda SL175, '02 Royal Enfield Bullet 500, '89 Yamaha FJ1200

Offline iron_worker

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Re: New Project 1972 cb500
« Reply #13 on: January 23, 2013, 06:25:50 AM »
I would just buy a new ignition switch with key. They aren't too much $. Probably less than you'd spend on a custom key.

IW

Offline zenocchio

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Re: New Project 1972 cb500
« Reply #14 on: January 23, 2013, 11:27:02 AM »
I would just buy a new ignition switch with key. They aren't too much $. Probably less than you'd spend on a custom key.

IW

That is what I figure out. I ordered a new switch with two keys. Hopefully I will be able to modify the front lock too.

I kind of like the look of the rusty tank, I wouldn't mind keeping it that look and just give a clear coat or something. I have the bike original tank and this one that came from a 750, someone made indents and tried to repair it with some bondo

Offline Vinhead1957

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New Project 1972 cb500
« Reply #15 on: January 23, 2013, 12:55:32 PM »
Read the number off the ignition switch and you may be able to get precut keys. I got extra ones that way

Offline zenocchio

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Re: New Project 1972 cb500
« Reply #16 on: January 25, 2013, 07:25:49 AM »
I'm getting inspired for the new seat. I'm planning to put the battery in the back under the seat cowl. I like the look of the long seats like the one below.
I'm planning to reuse my old seat pan and mounting the cowl on it and cover the whole thing with vinyl:

Offline zenocchio

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Re: New Project 1972 cb500
« Reply #17 on: January 28, 2013, 01:33:26 PM »
I had a lot done this weekend, I rebuilt the main wiring harness and wired almost everything up.
I am waiting to get the main switch by mail this week to test the electric system.

I am running aftermarket switches and I am trying to dot that put.
My light switches are separate for hi and low, and both have three connectors that I assume are power ground and to the dash light. I am right?

Next thing to tackle is the front brake, that is very loose and doesn't work. The reservoir is half full and the fluid is clear and seems new. If I am pressing the lever I can see bubbles forming in the reservoir so I am assuming that the first thing to do is bleeding the system. One of the brake lines looks cracked so I might have to replace that too. Anything else I should look at?
Thanks

Offline hondamatteo

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Re: New Project 1972 cb500
« Reply #18 on: January 28, 2013, 01:55:37 PM »
Make sure the reservoir is clean and spotless. Check if it leaks fluid where the handle meets the piston. If it does, oem rebuild kits can still be had. I would also take a look inside your calliper to make sure that is just as clean. Old brake fluid can dry up in there and cause the piston to stick. Just make sure everything is clean and spotless. Steel braided lines can be had by slingshot cycles if you choose too.
'74 CB350F

Offline iron_worker

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Re: New Project 1972 cb500
« Reply #19 on: January 28, 2013, 02:19:58 PM »
Yes a look inside the braking system is probably in order. Clean out all the old gunk that is inevitably in there if the bike has been sitting around and check to see if your piston or cylinder wall have pitting. Replace the seal and/or piston if needed. New lines are never a bad idea either. Cleaning out the master cylinder is also a good idea and rebuild if necessary. Dirt and junk plugs up the tiny passages.

I've read that a good way to bleed the system is fill it up with fluid and then zip tie (or something) the lever to the handlebar and just let it sit over night. If your passages are clear then the air should be able to work it's way out on it's own.

IW

Offline zenocchio

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Re: New Project 1972 cb500
« Reply #20 on: January 28, 2013, 06:16:31 PM »
Yes a look inside the braking system is probably in order. Clean out all the old gunk that is inevitably in there if the bike has been sitting around and check to see if your piston or cylinder wall have pitting. Replace the seal and/or piston if needed. New lines are never a bad idea either. Cleaning out the master cylinder is also a good idea and rebuild if necessary. Dirt and junk plugs up the tiny passages.

I've read that a good way to bleed the system is fill it up with fluid and then zip tie (or something) the lever to the handlebar and just let it sit over night. If your passages are clear then the air should be able to work it's way out on it's own.

IW
Make sure the reservoir is clean and spotless. Check if it leaks fluid where the handle meets the piston. If it does, oem rebuild kits can still be had. I would also take a look inside your calliper to make sure that is just as clean. Old brake fluid can dry up in there and cause the piston to stick. Just make sure everything is clean and spotless. Steel braided lines can be had by slingshot cycles if you choose too.

thanks guys!
I have been told by the PO that he did some works on the front brake, and i kind of believe him as the fluid as clear as new. I dont have any leak anywhere. might it be just too much air in the system?

Matteo,
where do you get your parts here in Vancouver?
thanks,

Offline hondamatteo

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Re: New Project 1972 cb500
« Reply #21 on: January 28, 2013, 08:35:54 PM »
If all looks clean then you can give bleeding it a try. I usually get a lot of my parts online (ebay and different online honda parts dealers) I have even bought a few parts at Carter honda motorsports in Granville island just cause they are close, if the part is still available.
'74 CB350F

Offline zenocchio

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Re: New Project 1972 cb500
« Reply #22 on: January 28, 2013, 11:37:37 PM »
If all looks clean then you can give bleeding it a try. I usually get a lot of my parts online (ebay and different online honda parts dealers) I have even bought a few parts at Carter honda motorsports in Granville island just cause they are close, if the part is still available.

Grazie Matteo!

Offline zenocchio

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Re: New Project 1972 cb500
« Reply #23 on: February 02, 2013, 04:11:47 PM »
it's alive! I started the bike today and it runs fine.
It was great hearing the sound of it after so many hours spent wiring!
The engine has developed a leak in te bottom part left side, I suppose it's because the engine hasn't been running for so long. What should I check? All the gaskets should be new as the engine was rebuild by the PO.

Offline zenocchio

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Re: New Project 1972 cb500
« Reply #24 on: February 04, 2013, 07:46:33 AM »
A new update. I took apart the alternator cover and found some oil in it. My guess is that the leak was from there, how is that possible? Is it supposed to be oiled?
The clutch was not disengaging when pulling it, what could it be?
« Last Edit: February 04, 2013, 04:54:06 PM by zenocchio »