Topic: Obscure electircal knowledge needed....

[jonboycox]

I have been stranded several times on my 77' 400F due to complete electrical shutdown. Dangerous especially when it happens in a low speed corner. I have traced the problem back to the red wire in the ignition assembly. I have had the entire assembly apart and it is obvious that the terminal connection where the ignition is plugged into the harness has a faulty prong on the red wire. Specifically, on the bottom of the ignition assembly, where the prong is rivited through the plastic to the small round terminal that gets bridged when the key is turned on. Its rivet is now loose and sloppy and making intermitant contact. I have tried folding the rivet edge over to stiffen the connection in combination with a coating of JB weld. It is now better, but still intermitant. I checked my spare parts bin and found an ignition that is very similar on the outside, but once opened reveals a different interior, so I can't scoop the parts. Is this just a difference in the year? Or, did honda have a couple of ignitions that they used depending on other variables? I realize this is pretty obscure.... 

[Bodi]

There are a few ignition switches that look roughly the same but have different contact arrangements. However, if the housing and mount are identical it should be the same switching. If you have the original key (a Honda key) the key number may tell what model it's from. The original switch was used on at least the CB400F and CBX, maybe other Honda models. No other non-Honda bike I know of has exactly that mounting arrangement, but all Japanese machines of the era used switches made by the same 2 or 3 manufacturers and they do look the same in a lot of ways.
The best solution in my opinion is to get the Emgo replacement ignition switch assembly and Hondaman's relay unit (or make your own). The Emgo switch is fairly well made but the contacts are not rated for the amps that the 400F puts through them, and it will overheat and fail eventually if directly installed. The relay solves that problem.

[jonboycox]

Thanks Bodi... the insides are different for sure, even the shape of the pin that registers the key to the turning plastic part. Also the two sprung metal bits that hide in the bottom and bridge the terminals are of a different shape. I should check again however that the pieces are not interchangable. In considering an EMGO ignition, which I have, my concern is having to have two keys, one for the ignition and one for the seat lock. Do you know if the seat lock has proper tumblers that need the correct key to operate? Or is the seat lock a low tech arrangment that only needs the approximate shape and size of key? Thanks for the help, your posts are always great......