CB750 SOHC Cafe Brat Experiment Build

ppg9944

New Member
Hi Guys,

I've been working on this 1975 Honda CB750. Not going to post a before pic right now but long story short. Bought the bike super cheap with the pistons rusted to the cylinder walls. So the block on this thing is off a 72 i believe, with 64mm domed pistons so the displacement will be 811cc.










I'm getting ready to start wiring this thing up except I've never done it before. The electronics are mostly stock except I have an ignition switch and fuse block from a 2001 honda magna that I want to use. Pamco Ignition along with 2001 Honda Magna Coils and the Koso Gauge.

Does anyone have any good resources to learn a little bit more about what I'm trying to accomplish. I've read the posts on this forum about electrical systems but I would like to know if there is something that's more about how to actually do it and what to look out for. Thanks
 
Thats an interesting setup ya got there. (Is that better guys?)

Do you have a specific question on the wiring or just 'how do I wire a bike'?

Here are a few general tips from a guy that tends to spend less effort on his wiring than he should:

-Dont use cheap connectors. 3M or better.
-Practice soldering.
-Draw out your custom diagram. This will help you 'connect' with the project.
-Use connectors to create sub harnesses so the wiring can be removed without cutting.
-Use heat shrink where applicable.
-Use grommets where applicable.
-Try to avoid using tape.
-Use fused links or a fuse panel. I see a lot of custom bikes with no fuses in them. Edit, i see that you have addressed this part.

You're gonna fix that seat, arent ya?
 
Loctite77 said:
Nice looking build. Where did you get that top triple tree from?


Yeah Son!

That's the stock vfr triple tree. I removed the ignition switch and mounted the Koso Gauge in that spot.
 
DohcBikes said:
Thats an interesting setup ya got there. (Is that better guys?)

Do you have a specific question on the wiring or just 'how do I wire a bike'?

Here are a few general tips from a guy that tends to spend less effort on his wiring than he should:

-Dont use cheap connectors. 3M or better.
-Practice soldering.
-Draw out your custom diagram. This will help you 'connect' with the project.
-Use connectors to create sub harnesses so the wiring can be removed without cutting.
-Use heat shrink where applicable.
-Use grommets where applicable.
-Try to avoid using tape.
-Use fused links or a fuse panel. I see a lot of custom bikes with no fuses in them. Edit, i see that you have addressed this part.

You're gonna fix that seat, arent ya?

I think I'm set on the connectors. I think I'm going to wind up hacking up the Magna harness I have and use some of those connectors. This whole wiring thing probably seems more daunting than it really should be also.


As far as the seat goes. It's actually upholstered. I just wrapped it up in plastic and tape when I was doing some fiberglass stuff. I'll pull that stuff off sometime once I'm closer to being done. For now it makes a nice tool bench.
 
ppg9944 said:
That's the stock vfr triple tree. I removed the ignition switch and mounted the Koso Gauge in that spot.

Is that also a VFR fork? Or a stock cb750 fork? Hard to tell.


Yeah Son!
 
Yea sorry. The whole front end is VFR expect the wheel is the stock cb750 wheel. I got thinner brake rotors for it and I had to shim one of the rotors a little bit. I had to figure out some spacers to get the wheel to fit in there since there was no room for a mechanical speedo drive, plus I didn't want one. I gotta figure out some sort of seals for the bearings still and then the front end will be good.
 
If you're wondering why a VFR front end. Well, my buddy had this interceptor through college and then once I picked this up and called him up to see if it would fit. He called bullshit, I called him on it. Long story short is that it pretty much bolted right up haha. Now I have dual disks and 37mm forks with anti dive.
 
On the subject of using connectors from the Magna harness; I'd recommend splicing wires as little as possible. The more splices, the more chance for a failure.

On the ignition switch, buy a universal switch and relocate it to the side. Cost you $20.
 
J-Rod10 said:
On the subject of using connectors from the Magna harness; I'd recommend splicing wires as little as possible. The more splices, the more chance for a failure.

On the ignition switch, buy a universal switch and relocate it to the side. Cost you $20.

I'm using the Magna switch, it has 3 wires compared to the cb750 switch which had 4. I had to splice some wires but I am trying to keep that to a minimum. I got a box of fresh terminals and a few connectors. Goal is to be able to use the connector plugs with brand new terminals on the wires.

It's a terribly slow process for me.
 
In comparing the diagrams I had to splice one of the wires going out from the switch into 2 separate circuits. One wire for the main fuse. One wire for the Power and one wire that splits into the headlight and taillight circuit.
 
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