Help with building '78 cb400t wire harness from scratch

jeramiah.conley

New Member
I'm new to the forum. Name's Jeramiah. I bought a '78 cb400t about 2 years ago and just found this forum which would have made my life a lot easier as most of those two years has been finding parts for her. I've finished the engine rebuild finally(there was no compression because the exhaust valve being carbon pocketed and then a cylinder head bolt popped the threading out of the crankcase top) and now all I need to do is build a new wire harness but wiring is not my strong suit. I could use whatever help you guys can offer. Treat me like I know nothing about wiring because...well I don't.


I'm now aware of the posts in the beginning of the forum. Checking those out to see what I can learn. I'll post any questions I have when I'm done.
 
After reading the 101 I think I should be fine! I know enough about wiring that I should be able to get everything set up but I'll definitely keep everyone posted on the progress and if I have questions! I dig this forum by the way. I'm planning a few more projects in the future already and it's awesome knowing there are knowledgeable people I can talk to about this stuff!

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Newer year for the same bike? Probably. There are usually some slight differences, but often times it's not enough to make a significant difference.
 
Well I'd like to find one that is brand new. New charge system, rectifier, the whole 9 for the electrical system. I'm sure there's some sort of issue with compatibility but are there any newer year models for the 400t hawk ii that still have any of that in production? Or do they make the rest of those parts for the 78 still? I know the wire harness was discontinued hemce why I'm building the new one from scratch. I would just rather build it basically ground up and start fresh with everything I possibly can if I'm doing the rebuild already.

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Sorry... I guess maybe I don't understand what you're after?

If your plan is to make a new wiring harness, how come you want to buy one?

Any OEM wiring harness you buy that isn't for your make, model, and year, is likely to require some changes to get it working. Sometimes those changes are minor and sometimes they're prohibitive.

Do you have the existing wiring harness? That's a good template for starting a new one. Honda is generally pretty good about not re-using wire colors, so you often times don't even need to unwrap the harness.
 
I have the original but the guy I bought it off of changed quite a bit. I'm going to be building the new harness. I'm referring to buying the rest of the items involved with the electrical system as well like the rectifier and fuse panel and all that jazz. Thank you for your help by the way. I appreciate it

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Oh, gotcha. That makes sense.

A lot of the components can and should be replaced with new. Regulator/rectifier is cheapish and is one of the first things I generally replace. Doing so will usually improve your charging capacity as well as the life of your battery. It's also a must if you plan to move to a LI-ION/LiFePO4 battery. Flasher relay will need to be done if you want LED turn signals (another recommended change).

For your bike, there's a guy who makes a new CDI system and sells it on eBay. I've used his stuff in the past on a few projects and it works very well. Pretty sure Ignitech makes a new box, too, but they'll be a lot spendier.

About the only part you'll likely have trouble getting new is the stator. Unfortunately, they're a common point of failure on the Hawks and the CM400/450s, so even finding used ones can be tricky.
 
jeramiah.conley said:
What is the piece that sits on the rotor and leads to the rectifier called?

The attached picture is a stator for the CB400T.

That what you mean?
 

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That's the pickup for the CDI. It should run to the CDI box rather than the rectifier. Blue and white wires if my memory is correct?
 
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