Author Topic: New (to me!) '77 CB400F - US model  (Read 38192 times)

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Re: New (to me!) '77 CB400F - US model
« Reply #270 on: July 27, 2019, 03:45:47 PM »
General rule for heating steel is never to quench it after heating, unless you know specifically that you need to change the properties intentionally. 

Heat treatable steel gets harder and more brittle when quenched,  so its a property you'd specifically ask for in that process. That's if it's of that metallurgy.

The gear lever you should be able to do cold ( don't try to bend it when installed though as you risk damage to shaft)  clamp the flat bit vertically in a vice with the rubber bit pointing upward,  not too tight as you are only needing to restrain it, then put an adjustable spanner on the flat piece right next to the rubber and twist it to correct angle.  It'll usually go fairly easily.

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #271 on: July 27, 2019, 05:13:09 PM »
Thanks guys - I was researching heat treating online, and although I understand the processes a bit, I wasn't getting any hints about what was preferable in my circumstance.

I'll try the side stand this afternoon; the gear lever is still on the bike and although I definitely planned to remove it before trying to straightening it, thanks for the reminder - it wasn't uncalled for!  ;)

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Re: New (to me!) '77 CB400F - US model
« Reply #272 on: July 28, 2019, 03:13:11 AM »
I think this shift lever has been repaired.  Can someone (maybe with the forward US-style foot pegs and non-linkage shift lever) confirm that this isn't the usual honda weld quality?  EDIT: the 4into2 replacement, pictured above, has no weld at all...

Click to zoom if so inclined:

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« Last Edit: July 28, 2019, 10:07:02 AM by mattsz »

Offline taysidedragon

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Re: New (to me!) '77 CB400F - US model
« Reply #273 on: July 28, 2019, 12:09:54 PM »
That looks similar quality welding to what's on my UK gear lever.
There's chrome over the weld so probably original.
Gareth

1977 CB400F
1965 T100SS

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #274 on: July 29, 2019, 02:37:33 AM »
Well there you go.  I just assumed that the OEM would have been a one-piece casting like that after-market job, and therefore my welded one must have been broken and repaired.

I bent it "back" to where it looks like it should be right, but without the bike present, it's hard to know!  We'll find out soon - easy enough to fine tune it later...

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Re: New (to me!) '77 CB400F - US model
« Reply #275 on: August 31, 2019, 11:00:58 PM »
I went to a local museum's classic motorcycle meet today; saw three CB400F's there, but all earlier than '77.  That late model US version really is the ugly bastard child, isn't it?  Fugly tank, upright bars and forward pegs...  anyway, I wonder if the owner of this one knows what a gold mine he has with those OEM headers in such great shape?

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Offline 10tenmen

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Re: New (to me!) '77 CB400F - US model
« Reply #276 on: September 01, 2019, 08:59:43 AM »
How do you know they are genuine bars ie what’s the giveaway sign thanks.

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Re: New (to me!) '77 CB400F - US model
« Reply #277 on: September 01, 2019, 12:17:39 PM »
How do you know they are genuine bars ie what’s the giveaway sign thanks.

Well, now that you mention it... I don't know they're original.  Although he acknowledged that the silencer wasn't OEM, he said the headers were, so I'm taking him at his word.

They do look rather shinier than the rest of the bike don't they?

Offline 10tenmen

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Re: New (to me!) '77 CB400F - US model
« Reply #278 on: September 01, 2019, 12:51:32 PM »
Agreed like you say if original they are valuable lol.

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Re: New (to me!) '77 CB400F - US model
« Reply #279 on: September 01, 2019, 09:53:14 PM »
While digging into my fuse block to help with a wiring question, I found this (click to zoom):

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To be honest, I didn't dig further and I'm not sure which "side" of the fuses this little bodge is on, but I know enough about how electricity moves through conductors to know that this isn't cricket!  The only reason I can come up with for this is perhaps the clips holding the fuse ends weren't gripping securely, so the wire pulls them tight.  Pardon my Français, but really, WTF?!?

It looks like the same kind of job done to hold the ignition switch connector to the broken switch: http://www.sohc.co.uk/index.php/topic,17461.msg153957.html#msg153957

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Re: New (to me!) '77 CB400F - US model
« Reply #280 on: September 14, 2019, 03:48:55 PM »
No response to my latest post, so just to be sure: that fuse box bodge is an electrical problem... isn't it?

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Re: New (to me!) '77 CB400F - US model
« Reply #281 on: September 14, 2019, 04:36:09 PM »
Take it you mean just the twisted wire there?

Looks like it's been initiated to cope with intermittent connection as you suspect.  Wouldn't in itself do anything wrong if on supply side but would increase fuse rating if on outbound terminals.

(I use a jumper in that location to get a car fuel pump going by taking a supply from cigarette lighter circuit in the event of problem failures)

Looks like the fuse board has problems causing no start or complete stopage on occasion.  In cricket terms "light stops play"  ;D

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #282 on: September 14, 2019, 05:12:23 PM »
Take it you mean just the twisted wire there?

Looks like it's been initiated to cope with intermittent connection as you suspect.  Wouldn't in itself do anything wrong if on supply side but would increase fuse rating if on outbound terminals.

Thanks K2-K6... your "ifs" got me thinking about that, too, so I removed the fuse block to actually examine which wires on which side of the fuses were shorted.  As it turns out, that twisted wire is connecting the black/red and the brown/blue wires.  Looking at the UK wiring diagram, I believe this would create a short circuit between the "park" and "headlight" positions of the lighting switch on the right handlebar control, so any position other than "off" would illuminate them all.

But this is a US spec bike, with no light switch, which is wired to have the headlight always on when the ignition switch is on - except when the electric start button is being pressed - at that point the headlight is supposed to go off until the starter button is released.  With a short across those two wires, the headlight will always stay on, even when the electric starter is being used, bypassing the protections built into the circuit... such as they are.

I think I'll fix it...  ;)

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Re: New (to me!) '77 CB400F - US model
« Reply #283 on: September 14, 2019, 05:47:38 PM »
I feel it's definitely worth while to get it properly sorted and debugged,  just makes using it easier too.

I'd do the same.

Offline Lobo

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Re: New (to me!) '77 CB400F - US model
« Reply #284 on: September 16, 2019, 01:23:29 AM »
... whilst I don’t have the US wiring diagram mattsz, I’m not sure how connecting the Park & HL will bypass the starter button ‘protection’ - ie I’d have thought the ‘protection’ will continue to work as designed?
My guess at this bodge is that there’s been a break in the Black/Red feed (to the fuse holder) ... and so the PO has jumped the two together.

Has the PO therefore solved the problem and (lazily) restored the lighting to normal road light functioning?  (at the expense of proper Park light function)

Simon.
« Last Edit: September 16, 2019, 03:02:22 AM by Lobo »

 

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