Topic: 1977 cb750F, how to bypass ignition switch!? Help! need to get home

[needyspeedy]

I am on the road far from home.  my ignition switch crapped out.  I have unplugged the swich harness, anyone know which wires i need to jum in order to get the bike to operate in "on" mode?  it seems that if i connect the red wire with any other wire, the bike is on, but it blows fuses, i need the correct arrangement and all the wiring diagrams online are ilegible.  What color wire to what wire?  additionally, the connecter has 5 wires to work with.  two brown wires, one brown/white wire, one black wire and one red wire. Please I need help! Thanks all!
dave

[Jerry Rxman Griffin aka MuthaF'er]

NeedyIndeedy,

DETAILS! You have failed to let us know which road you are on in what town and where home is or what the actual switch problem is. Plus this is your first post. Sure you're not hot wiring a bike? Sorry but I had to ask. I don't wish to seem to contribute to criminal activity. I'm sure we have a member close that would be glad to help or we might be able to get you another switch or the base for it. Perhaps a bed, hot shower and/or a meal and beer. That's where I'm coming from.

Anyway, my Honda Shop Manual tells me the Red wire is the hot wire that leads back through the fuse box to the solenoid and is labeled as BA on the ignition switch. The Black wire is labeled IG on the switch and is the ground. The schematic for the Ignition Switch Arrangement shows On1 as having the BA/Red and IG/Black connected.

Blowing fuses sounds like a short to me. Don't forget to check the wiring in the right handlebar switch for shorts. My 75F had one of the wires leading into the ignition switch rubbed raw on the steering neck. Now I'm not a wiring expert but I'd expect the red (hot) connected to the brown or brown/white to start turning on some lights somewhere and if the fuse blows then find a short.

Hope this helps. Have a safe trip home. When you get back home we expect a proper introduction along with pictures.

[bryanj]

red to black should make it run but no lights at  rear

[rustrocket92]

Sounds fishy to me! First post and looking to hot wire a members bike. You guys better go check your parkin spots. Just kidding I would hate to be stuck somewhere on the side of the road or with a bunch of people that don't know anything but where the gas goes and " the nearest dealer is in? " but thats what good friends are for. As for as wiring goes it took me forever to get everything to work let alone without the key switch.

[Hush]

OK so he either got home or stole a bike by now.
But for future lawful reasons, I'm guessing that adding the red to all the black and brown wires would liven the whole system up.
Not sure why he would be blowing fuses by doing that.
Maybe he should have said "hey I snapped my key" or "lost my keys" would have sounded better.
Damn we are a suspicious bunch, I guess the naive world when our bikes were new has long gone.

[needyspeedy]

This is a bone stock bike.  But this is where its funny.  red to black, bike starts, lights on.  red to brown, bike starts, lights on.  its seems like to connecting the red to any of the wires of my choice gets me going.  I chose red to black, both tailights and headlights and turnsignals are on.  in any case I am on Highway onel, currently at Motel 6 in San Simeon, on my way to NYC!! unless i keep getting problems!  I have tons of pictures, join my facebook, email is davidtnguyen@yahoo.com, i'm blogging the trip.

I rode the bike wired as described above, before i got your replies to this motel 6, where i am now.  fuses haven't blown.  No brown wires connected yet i have lights!!  oddly enough, a mile before the bike went dead, i was passing a car, revving up to almost redline, faulty regulator? then it started puttering, then dead.  all fuses were good, battery was good, i determined it was the key switch.  I can't find any faults in the harness.

[needyspeedy]

NeedyIndeedy,

DETAILS! You have failed to let us know which road you are on in what town and where home is or what the actual switch problem is. Plus this is your first post. Sure you're not hot wiring a bike? Sorry but I had to ask. I don't wish to seem to contribute to criminal activity. I'm sure we have a member close that would be glad to help or we might be able to get you another switch or the base for it. Perhaps a bed, hot shower and/or a meal and beer. That's where I'm coming from.

Anyway, my Honda Shop Manual tells me the Red wire is the hot wire that leads back through the fuse box to the solenoid and is labeled as BA on the ignition switch. The Black wire is labeled IG on the switch and is the ground. The schematic for the Ignition Switch Arrangement shows On1 as having the BA/Red and IG/Black connected.

Blowing fuses sounds like a short to me. Don't forget to check the wiring in the right handlebar switch for shorts. My 75F had one of the wires leading into the ignition switch rubbed raw on the steering neck. Now I'm not a wiring expert but I'd expect the red (hot) connected to the brown or brown/white to start turning on some lights somewhere and if the fuse blows then find a short.

Hope this helps. Have a safe trip home. When you get back home we expect a proper introduction along with pictures.

Jerry, what does you manual say about the other wires that need to be connected for on1? my blurred copy looks like its says brown/white to brown.  But I have two brown wires!

[Jerry Rxman Griffin aka MuthaF'er]

PA (parking) & TL2 are brown. TL1 is brown/white. This is from the connector/switch diagram.

Gets a little iffy here. Every manual I have, Clymer, Chilton, Haynes, Honda, all have minor errors, The Honda Shop Manual connector/switch diagram seems fine but the "Ignition Switch Arrangement" diagram shows this:       
                 BA  IG  TL1  TL1  PA   (Obviously from the connector diagram TL1 IS Br/Wh & TL2 is Br
          OFF                                  but this chart shows TL1 twice and no TL2/Br so I think the 2nd   
          ON1  X--X     X---X            TL1 (Br) on this chart should read TL2)
          ON2  X---------------X
      COLOR   R  Bk  Br/W  Br   Br

I'm thinking normal running sequence will have R(BA) & Bk(IG) connected for ignition and Br/W(TL1) & both Br(P & TL2) connected for lights. ON2 is for tail light only for emergency parking at night beside the road so R & Br I think. Either way it looks like both B's are connected together into one Br wire so they would both be connected at the same time. My first key stop turns on the front running lights, the head light, and tail light. The 2nd key stop only turns on the tail light. 

Sure hope this helps. I gotta hit the sack. Report back in. I'm working tomorrow but I'll check in before I leave at about 10AM MST. We have a bunch of guys in CA. You have a long way to NYC with a bunch of us in between. If you're coming through Colorado let me know. We need to find you a switch along the way. If available you may have to have a dealer ahead of you order and have waiting for when you get there. The contact bases may be available but probably not stocked. Parts N More has them but they are after market and are reported to not be as good but better than what you have now.

[needyspeedy]

Thanks Jerry.  I'm taking the southern route, california, vegas, grand canyon, austin texas, new orleans, to the east coast and then up!  any of you on this  post can give me a holler if on this route.
Dave
email to my iphone, davidtnguyen@yahoo.com

[Gorms]

Short answer: red to black, and brown to brown/white.

[Spanner 1]

gorms +1 for correct, properly fused operation....Main fuse must be 15A, Tail fuse 7A.... good luck on your trip.

[Jerry Rxman Griffin aka MuthaF'er]

Thanks Jerry.  I'm taking the southern route, california, vegas, grand canyon, austin texas, new orleans, to the east coast and then up!  any of you on this  post can give me a holler if on this route.
Dave
email to my iphone, davidtnguyen@yahoo.com

Smart move. It's been cold and snowy in Colorado but it's pretty. If you did come this way I've always wanted to strap the skiis to the bike and head for the slopes. We have 2 areas open so far.

How about doing a trip report here too?! I've avoided all the "social" sites except this. I don't need ex girlfriends, wives, and potential kids tracking me down. I left 'em behind and thats a good place for them   

Hope the electricals work themselves out.

[brewsky]

On my 750 K8, I have no voltage to the brown taillight wire at the switch in any switch position.
After taking the switch apart and looking at the wiring diagram, it doesn't look like there is any connection between BAT (red) wire and TL1 or TL2 (brown) wires thru the switch.
Where is the source of voltage to the brown taillight wire??
Thanks

[Spanner 1]

The brown wire rec. +12v from the brown/white wire at the ign. switch. The brown/white wire passes thru' the 5A tail-light fuse and rec. it's power from the BLACK in the headlight shell ( the brown/ white changes to a brown/ blue tracer before the fuse ). So check fuse carefully  and corroded fuse clips ( will make no power at switch )...also check for brown/blue to black in shell....

[Don R]

For a minute there I was afraid needy was still out there trying to get home for 3 months. Whew, hope he made it OK.

[brewsky]

Thanks Spanner!
I can't read the factory wiring diagram I have (too blurry), and the Clymers is not even close.
There is no voltage at the brown/white wire either, so at least now I know where else to look.

[timmerk]

Sorry for posting on such an old topic, but I thought it would make most sense to keep the related question on this topic, since it also applies to starting a 77 CB750 without the ignition.

I can't tell what wire colors are which on mine since they are in bad shape. However, while waiting on a new ignition from eBay, I would like to work on getting it started this weekend. I took the connector off of the old ignition switch which has 5 contact points connected to the 5 wire connectors that plugs into the wire harness. I attached a drawing of what it looks like. Anyone know which points I should connect to start the bike, or which color wires connect to each connector so I can use the information posted above? Thanks!

[scottly]

At the plug on the harness, jumper the red wire to the black wire. You could also connect a jumper from the battery plus terminal to the black wire on the regulator, which may be easier.