Author Topic: New (to me!) '77 CB400F - US model  (Read 38164 times)

Offline Bryanj

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Re: New (to me!) '77 CB400F - US model
« Reply #195 on: January 21, 2019, 10:02:19 PM »
Yup, reserve fuel still goes through the srainer on normal through the tubeso seal position means nothing.
As to the tube staying in the tank and being flush---they all do that sir just sorta happens.

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #196 on: February 04, 2019, 09:46:02 PM »
Just recently done a cbx 550 so i can definitively tell you that if you do not want a leak the strainer pushes into the petcock then you fit the washer/O ring before fitting the assembly to the tank

Yup, reserve fuel still goes through the srainer on normal through the tubeso seal position means nothing.
As to the tube staying in the tank and being flush---they all do that sir just sorta happens.



I can't get my head around this apparent contradiction - the o-ring must go on over the strainer if you don't want leaks, but then the strainer doesn't stay there, but ends up "outside" the o-ring, flush in the tank - and they all do that?  Shouldn't they all leak, then?

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #197 on: February 04, 2019, 10:03:54 PM »
Regarding the clutch...

It seemed to work fine three years ago when I rode it last, but now it's become extremely difficult to pull.  I won't hazard a numerical guess about the actual force required, but it's not safe to ride in this condition.  It can be fully pulled, and it does return on its own, albeit a bit sluggishly.

Aside from the obvious possibility of a binding cable, what else could be the trouble?

Might this be expected of a bike that's been sitting for a couple of years?  In other words, should I be thinking about solving this problem before I try running it (whenever that turns out to be)?  Or might it sort itself out with some oil circulation and exercise?

Almost certainly cable and as a hint DO NOT oil an original cable as the onner is rubber coated and the outer nylon lined, oil tends to "swell" both and make the cable tight. Aftermarket cables may dispense with one or both of the linings and be safe to oil but i dont comment on that!!

Bryan - after our discussion on the other forum about clutch cable sources, I went looking and found a couple, but while they show photos of cables correctly tagged with part numbers, I can't get them to confirm that they're actually correct - one ebay guy just promised that what I see is what I get (despite a reviewer claiming he didn't get what was pictured when he ordered).  Partsnmore in Canada has never heard of a high-bar version of the bike, so can't comment, but asked for measurements.  So, I went to the bike today to remove the clutch cable...

Recall your comment above about the cable.  Now take a look at the photos:

I barely got one of the clutch cover screws off - rusty!

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This doesn't look great:

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Water must have gotten in through the cable opening?

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I was able to exercise the clutch with great difficulty, and it returned to rest, but now that the cable is out, I cannot budge the wire in its housing!

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Yep, new cable (and cover plate screw) time!  Any way to prevent that moisture intrusion?

Offline Bryanj

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Re: New (to me!) '77 CB400F - US model
« Reply #198 on: February 04, 2019, 10:28:56 PM »
Looking at the clutch cable will the nipple on the end go through the hole in the screwed adjuster? Also give me length of outer cable and inner cable.
Yes water gets in through the adjuster but that cover is supposed to come off at service to check clutch adjustment and most mechs of my era  used to lube everything excessively!!

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #199 on: February 04, 2019, 10:57:21 PM »
The filter fits inside the tank spigot, it's flared at the bottom end so it can't disappear inside the tank, it's a tight fit inside the spigot so no petrol can get to the fuel tap without going through the filter, the O-Ring just seals the inner collar on the tap against the bottom of the tank spigot, the large outer nut compresses it against the spigot so it seals and stops any leaking petrol. Most people tend to overtighten the outer nut which causes the O-Ring to expand, flatten out and get stuck in the threads of the outer nut.  Hence why yours looks in pretty poor shape. Don't worry about the filter fitting inside the tap, so long as it fits inside the tank spigot it's doing it's job.

Oddjob, that's certainly the way I found mine, but others are suggesting other possibilities.  One thing I think I may not have considered, is that I think the '77 USA models have a different petcock than the earlier ones, so we may have been comparing apples and oranges...

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #200 on: February 04, 2019, 11:05:38 PM »
Looking at the clutch cable will the nipple on the end go through the hole in the screwed adjuster? Also give me length of outer cable and inner cable.

Bryan, it's hard to tell since I can't budge the cable, but after measuring it does appear that the clutch housing end nipple would fit into the threaded adjuster if I could pull it - the nipple measures about 5.7mm at its widest, and the inner diameter of the adjuster seems to be about 6.3mm, although it's hard to measure with the cable in the way.

Dimensions...
  • Inner cable length, ball-end to ball-end… 45 inches
  • Outer housing length, metal sleeve at handlebar to end of adjustment screw at clutch housing… 41-5/8 inches
  • Adjustment screw at clutch housing… 1-11/16 inches
  • There’s also a protective sleeve around the outer housing, about 13-1/2 inches long, which starts about 17-1/2 inches from the metal sleeve of the outer housing at the handlebar

Offline Bryanj

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Re: New (to me!) '77 CB400F - US model
« Reply #201 on: February 05, 2019, 09:02:20 AM »
I will have a look at my box of assorted cables and let you know. As your cable is fubared i would clamp the end of the outer by yhe adjuster in a vice and use a spanner to turn the adjuster away from it with lost of WD

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #202 on: February 05, 2019, 11:43:41 AM »
Looking at the clutch cable will the nipple on the end go through the hole in the screwed adjuster?

I will have a look at my box of assorted cables and let you know. As your cable is fubared i would clamp the end of the outer by yhe adjuster in a vice and use a spanner to turn the adjuster away from it with lost of WD

I wasn't quite sure of the significance of your question, but I had a look at some parts diagrams and now I think I just learned something new - the adjuster isn't part of the cable, is it?  I just thought it was all one piece, since I hadn't seen any detailed images of them separated, and mine are fused together.

I think I can find a cable here, as long as I am willing to take a chance on a seller who doesn't really know what they're selling and relying on photos to inform buyers...

I'll separate the pieces, I'll have to do it anyway.  Only problem I foresee is that the adjuster's socket where the cable housing seats could be rusted, and difficult to clean well.  That's another part that's hard to find, I've only found one so far - new stainless steel from Yamiya750.com.  Maybe if it's not too bad I can get someone to blast it clean...

EDIT: I was searching for the wrong part number for the adjuster - there's a few around, but I haven't yet found any in the US, and nothing on ebay...
« Last Edit: February 05, 2019, 11:59:02 AM by mattsz »

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #203 on: February 05, 2019, 04:54:45 PM »
Dimensions...
  • Inner cable length, ball-end to ball-end… 45 inches
  • Outer housing length, metal sleeve at handlebar to end of adjustment screw at clutch housing… 41-5/8 inches
  • Adjustment screw at clutch housing… 1-11/16 inches
  • There’s also a protective sleeve around the outer housing, about 13-1/2 inches long, which starts about 17-1/2 inches from the metal sleeve of the outer housing at the handlebar

So the highlighted dimension is not correct - I measured the outer housing without the adjuster, it's 40-1/4 inches...

 :-[

Offline Bryanj

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Re: New (to me!) '77 CB400F - US model
« Reply #204 on: February 05, 2019, 04:56:25 PM »
As you need to keep the adjuster and the cable is scrap a measure of mechanical violence is OK

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #205 on: February 05, 2019, 05:00:30 PM »
As you need to keep the adjuster and the cable is scrap a measure of mechanical violence is OK

 ;D

Not too much violence needed, cable housing in a vice as you said, and the adjuster "wrenched" right off.  I cleaned it off with a wire brush and I'm soaking it in white vinegar for a day or so to see if it helps it - a small test before I try it inside the fuel tank?

Offline Bryanj

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Re: New (to me!) '77 CB400F - US model
« Reply #206 on: February 05, 2019, 08:47:48 PM »
I have a cable that is longer than those measurements but approx the same "free play" you can have it for postage but that is probably more than a local e bay purchase!

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #207 on: February 05, 2019, 09:05:55 PM »
Thank you Bryan - I don't know how much the shipping would be, but the ebay guy I mentioned earlier has been very helpful with trying to sort out if it's really the right cable, and he's charging US$20 including shipping, so based on all that I'll probably go that way...

Offline Bryanj

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Re: New (to me!) '77 CB400F - US model
« Reply #208 on: February 05, 2019, 09:23:32 PM »
No problem, one of the hazards of living opposite sides of the pond!!

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #209 on: February 10, 2019, 12:09:50 AM »
So I soaked the clutch adjustment bolt in white distilled vinegar for a few days, along with some fine filing, and it came up pretty neat and clean.  I'll reuse it, with plenty of lubrication/rust prevention.

The clutch lever's pivoted cable mount end is pretty badly rusted where the cable attaches.  I'd like to try to reuse it; can I safely soak it in vinegar as well?  Not sure what kind of finish it has, and whether it will handle it...



Also, where the lever attaches to... umm... whatever it attaches to with that nut (clutch adjusting bolt?)... the lever seemed sort of loose and a bit "floppy?" even though the nut was tight.  Is that normal?

 

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