Wire Diagram

[D.horse]

I have just bought a 1979 Honda CB 650.

I am going to attempt to CAFE it. To do this i am going to have to move all the electronics to the back cowl. I plan to make the cowl out of fiberglass and put the battery and as much of the electronics back there that i can. I found a diagram online of a basic wiring diagram for a situation similar to mine, but i have a few preliminary questions before i starting any fires.


I have read the to tagged posts on this form, and i read about the size fuse I should use for a given gauge of wire..... Should i really be using a fuse that is close to the maximum of the wire capacity? Or should it be set to something like 60%? example a gauge 10 wire should use a 30A fuse or a 20A?

And as for grounding something... Is the best thing to use as a ground the frame or the engine block?


How does the wiring diagram look below? I plan to do almost everything that is on the diagram except i wont have a high/low beam switch. Do you guys have any suggested wire gauges for a 12V 12Ah battery?

Suggestions or warnings?

 

[ILoveThumpers]

...Should i really be using a fuse that is close to the maximum of the wire capacity? Or should it be set to something like 60%? example a gauge 10 wire should use a 30A fuse or a 20A?...

Follow the guidelines. 30A fuse for 10ga wire. If you use a fuse with a lower rating, you're not hurting anything but you're also not going to be able to use the full capacity of the wire.

...And as for grounding something... Is the best thing to use as a ground the frame or the engine block?...

What are you grounding? Generally, the frame is grounded and everything grounds to it. (Including the motor) But it's not uncommon for ignition to be grounded to the engine. Plus the starter, electric fuel or oil pumps, etc.

...Do you guys have any suggested wire gauges for a 12V 12Ah battery?

The wire gauge isn't related to the supply, but the load. The wire size should be appropriate for the load you place on it. For instance, 10 gauge wire is overkill for 90% of your bike but undersized for your starter.

...Suggestions or warnings?

It sounds like you should do some more reading and research before jumping in too deeply. The safest thing to do is to simply emulate the factory harness as closely as possible, simply omitting the circuits you don't need.

-Deek

 

[D.horse]

Thank you for the reply ILoveThumpers.

I do think that i need to do more reading as well, I was just trying to see if there was anything alot of people screw up right a way that i should know about. I need to pull the Carbs this weekend, and i was thinking about removing the wiring harness when i do that. that way i will be able to look at it closely and go from there.

I did notice that when a user mentions that they want to use a Li-ion battery everyone says they need to change up the charging system so nothing gets screwed up. Are they refering to just updating the regulator to something more modern?

 

[ILoveThumpers]

Are they refering to just updating the regulator to something more modern?

Yeah, mostly. LiIon batteries are very sensitive to over-charging. In fact you can ruin one very quickly with as low as 14.8 volts. 14.5 volts is the maximum and a lot of "regulated" charging systems can get up to 16 volts!

If your bike has a separate rectifier and regulator, you can replace them with a modern combination rect/reg that will clamp the stator output down to under 14.5v.

When you're talking electrics on old bikes, as long as you've got a main fuse and an ignition system fuse (and possibly a lighting fuse, because that's where most of the problems occur) you can't really damage anything beyond repair, you'll just blow fuses!

Do you have a stock harness to reference?

-Deek

 

[D.horse]

Do you have a stock harness to reference?

-Deek

Yes I do, It is still on the bike right now, I am waiting on some wire indicators (so i can mark where they cam from) before i take it off.

the bike in this video seems like it has a similar setup to what i want to do. Although it does seem mostly stock with just the battery moved.

http://www.youtube.com/watch?v=558eLFpPgbY

 

[Sonreir]

Take it one circuit at a time and do regression testing (testing of ALL the electrical functionality) after each new circuit is added. This way you can immediately identify any mistakes that have been made.

I think the number one problem people face with wiring is trying to do too much at once. Until you've wired a few bikes, I don't suggest trying to tackle a whole harness at once. Just do one circuit at a time, and wrap up the finished product. Then you have a harness.

 

[D.horse]

Take it one circuit at a time and do regression testing (testing of ALL the electrical functionality) after each new circuit is added. This way you can immediately identify any mistakes that have been made.

I think the number one problem people face with wiring is trying to do too much at once. Until you've wired a few bikes, I don't suggest trying to tackle a whole harness at once. Just do one circuit at a time, and wrap up the finished product. Then you have a harness.

Thanks man, That sounds like advise that comes from someone that has been around this for a while.

 

[Sonreir]

I may have done a few before... :

 

[ILoveThumpers]

Yes I do, It is still on the bike right now..

Yeah, you're home free then. The factory harnesses, though old and busted after 30+ years of abuse, were solid and reliable when new. Unless you're dealing with a brit bike, you can duplicate a factory harness with zero issues.

-Deek

(I'm joking about the brit bikes... I'm still bitter about my days dealing with Lucas electrics on Triumphs/MG's/Lotus...)