"Hi guys. I'm not really new to this forum, but all new to posting questions, hope you guys can help me out with some basics on the electrical and some rewiring.
I'm doing a complete rebuild of a Honda CB400F from '76, but learning it all as I go from manuals and forums. I'm finally at the electrical and I've been searching the web for ages and been looking at similar topics, but I can't seem to find the answers I'm looking for - something precise. It looks like everybody got different ways of doing their wiring, so every topic and set of answers goes in every direction. But anyways, to the questions
First of all I've been reading about wiring and electrics for a while, so I got a basic knowledge of how it all works and how to read my wiring diagram, but as I mentioned; this is my first time doing this, so bear with me.
Wiring diagram:
http://www.cmsnl.com/classic-honda-fansite/honda_wiring_diagrams/CB400F.jpg1) Grounds: Just painted the bike, so I reckon I need to scrape some of the paint off to get good grounds? How do I make sure the grounds are good? Bare metal, a washer and a bolt? How many grounds do I "need" on a CB400F? Is the Negative from the battery going down to the engine mount on the right side of the bike and then the green ground wire to the battery box mount? That should make the frame to ground and the green should mount the overall ground to the frame, right? So with the green wire grounded, would it be ideal to ground indicators and controls to that, instead of grounding it to frame? I got new indicators, taillight and headlight.
The original ground is a hefty cable from battery "-" to the upper rear engine mounting bolt, battery side. If you want electric start you need that big wire. Clean frame paint off both sides of the frame tab where it touches the wire terminal and the engine. Most components ground via green wires, some via their mounting bolts or from contact to metal. You need to have a smaller (18ga?) ground wire bypassing the steering bearings - from the main frame to the turning part.2) Identifying wires for new parts. I got some new parts home and I want to make sure which wire goes to what, before mounting it - just to be safe. My indicators got got a Red and a Black wire, how can I tell which is ground? Same question with a new taillight and speedo. Got a new speedo with light for indicators, high beam, and all that, how to tell the wires apart? My new headlight came without wires at all, I reckon the center pin is ground, then one side low beam, the other high? Again what is what? Sorry if this is just a stupid simple question, but I have to learn it from somewhere
As a rule red will be positive, Honda harnesses have black for positive as it's switched and fused battery power. The headlight power plug is a standard and the connections are easy to find with a web search. For the indicator lights, standard 9V battery will light them enough to tell which is which. LEDs only light with plus and minus correct but will not be damaged if connected backwards.3) Rewiring controls. So I'm trying to rewire my killswitch and ignition key switch. This is where it gets confusing for me. I want to move the ignition switch under the seat, so the original is way to bulky. I'm probably going with an ON/OFF key switch and removing the park positing. Is it OK to wire a switch with two poles with two wires on each, so I got Black and Brown on one side and Red and Brown/White on the other?
The Honda wiring schematic is complicated but complate for the OEM wiring. The keyswitch is particularly complicated. For a SPST switch, RED from the MAIN fuse (NOT direct from the battery) goes to one terminal, BLACK to the other terminal. Connect brown and brown/white together (solder and tape or shrinksleeve) That way the switch should turn on both engine and lights, right? The problem is amps? The switch I got now is a mini switch, only 2A 125V / 4A 250V. The wires in and out of the original ignitions switch doesn't seem bigger than the others, but as I can understand, the power to most of the bike runs through here? Is it possible with only 4A or with a relay?
You will need relays. The amp ratings for these type of switches are much lower for DC than for AC. Relay wiring will be complex but it isn't crazy hard. Got absolutely no experience with really btw. The same with the kill switch; I was thinking of running the kill switch under the seat - not using at as a safety-switch, but as a small security against theft
The kill switch is close at hand for very valid safety reasons - try reaching across to where you want the switch with your right hand as a bike in gear with a stuck throttle isn't so unusual. I say leave it on the bar.. I want to run 5 toggle switches in a series (SPST - ON/OFF/ON), but again I got some tiny ones, so they don't ruin the classic look of the bike. But the amp rating is again low; 6A 125VAC / 3A 250VAC. Would this be fine?
No. You're putting 5 failure points in a chain. Plus the amp rating is too low. Forget this idea: bike thieves just lift the things into vans and drive off, hotwiring is totally last century. I was thinking of just wiring them between the Black and Black/White to the coils. Just be sure. When wiring a series of toggle switches, should I run either the Black or Black/White through the middle pin of the first switch. Then either take the right or left pin and run a wire from there the to the middle of the next one and then again either run a wire from the right or left to the next middle pin, and so on?
There is no SPST ON-OFF-ON switch, the terms are contradictory. An SPST switch can only have OFF-ON and only two terminals.A ON-OFF-ON switch would be SPDTMaybe relays could be a fix to some of the issues here?
4) Rewiring controls. I'm also rewiring my controls while I'm at it. Again toggle switches and momentary switches. Momentary switches for horn and starter. Would horn button be Light Green on one side and ground on the other?
Yes Just running the ground directly on the green?
Confusing: horn itself connects to ignition power (black) and light green, to beep , it grounds through the switch - to the handlebars on the stock unit. Your switch needs the light green wire and a good ground, wire or frame. And the same with the starter button Red/Yellow on one side and ground on the other. Would a small momentary switch be alright handling the wire to the solenoid?
How small? There is a powerful inductive kickback from the coil that eats switch contacts, some switches are better than others For high/low-beam and indicators I got toggle switches again (SPST - 6A 125VAC / 3A 250VAC). This should be fine I believe? With the High/Low-Beam i got 4 wires originally. I reckon i need high (blue) on one side and low (white/black) one the other. And then a power supply? Would this be the black (hot?) or is the brown/white running from the ignitions?
Br/Wh is the instrument light power. Or do I need both?
black to centre pin, headlight LOW and HIGH to the outer pins. It also turns the front markers off for high beams: I suggest you forget (don't use) the markers as they are complex to connect properly Same with the toggle for indicator lights. Grey from the flasher relay in the middle pin and then Orange and Light Blue one the right and left?
The original flasher switch is complex because it switches the front marker lights off for the flashing side. Without markers, you're correct.
Note that DPST switches connect the centre pin to the outer pin opposite the lever direction.I got manuals, wiring diagram, soldering iron, wires, connectors, multimeter and probably some other stuff lying around.
have a fire extinguisher handy when you power it up for testing.Sorry for the long first post, but I find it easier to help if you have all - or at least most - information from the start. Thanks guys
// Jonas"