Author Topic: New (to me!) '77 CB400F - US model  (Read 38175 times)

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #150 on: November 27, 2018, 10:42:32 AM »
I just checked mine. 5 x 18mm countersunk head and it does fit the Speedo drive as well.

Thanks taysidedragon!  Sounds like a couple of mm length makes no difference in this instance...

Are there any threads which focus on mistakes or omissions in the technical information most of us seem to use?  I've been reading through earlier posts as I've had time to spare, and I occasionally come across discussions similar to this one, people looking for info about parts or discussing misinformation in the books - for example, typos or outright errors in the Haynes, Clymer or Honda workshop manuals, missing items from parts catalogs (like this screw)... it would be nice if there were a spot a newbie like me could go and make note of these issues...

Offline Nurse Julie

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Re: New (to me!) '77 CB400F - US model
« Reply #151 on: November 27, 2018, 10:52:44 AM »
We have a section for errors

http://www.sohc.co.uk/index.php/topic,13453.msg106009.html#msg106009

Not too much in there but the usual saying is 'don't believe everything you read or see' especially if was translated from Japanese to English fifty years ago !!!
LINK TO MY EBAY PAGE. As many of you know already, I give 10% discount and do post at cost to forum members if you PM me direct.
https://www.ebay.co.uk/sch/julies9731/m.html?item=165142672569&rt=nc&_trksid=p2047675.m3561.l2562

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #152 on: November 27, 2018, 11:44:11 AM »
Thanks Julie!

By the way, I finally got the bike into bed for the winter - in my neighbor's garage, which is more like a large walk-out basement with big opening doors.  It's unheated, but the bike is far from the doors and no vehicles use the space, so there won't be any standing water from snow melt off a car - like there would be in my tiny garage.  I've got the fuel tank, carbs and front brake parts in my own warm basement, hopefully I'll find the time to rehabilitate them over the winter...

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #153 on: December 04, 2018, 01:58:25 PM »
I'm starting a shopping list...

Based on the appearance and condition of the front brake reservoir diaphragm (http://www.sohc.co.uk/index.php/topic,17461.msg149647/topicseen.html#msg149647) and the piston/caliper/pads (http://www.sohc.co.uk/index.php/topic,17461.msg149803/topicseen.html#msg149803), should I just assume the master cylinder should be rebuilt (or replaced with a pattern one)?  Will I know if I dismantle it and examine the condition of the parts? I don't really want to spend the money if it's not necessary, but it could be full of 40-year-old parts, and it is the brakes, after all...

Same question with the carbs, too, I guess - should I dismantle them and examine the jets, etc, to determine a course of action, or does one usually just "play it safe" and have a complete rebuild kit on hand?  How will I know if a good cleaning is enough, or whether I should replace all the replaceable bits?

Offline Laverda Dave

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Re: New (to me!) '77 CB400F - US model
« Reply #154 on: December 05, 2018, 10:09:29 AM »
I tried to repair the original front caliper on my 400/4 but it was beyond help with both the fluid union and the bleed nipple snapped in the housing. I bought a pattern caliper from DSS along with a master cylinder repair kit. The master cylinder was an easy rebuild. The hardest part is removing the internal circlip to enable piston removal. You need to buy a cheap pair of long nose or circlip pliers and maybe grind the ends down to fit. Easy job to do though and you keep the original master cylinder with the correct exterior finish, the pattern ones are painted black.
1976 Honda 400/4
1977 Rickman Honda CR750
1999 Honda VFR 800FX
1955 750 Dresda Triton
1978 Moto Morini 350 Sport
1978 Honda CB400/4 'Rat' bike
1982 Laverda 120 Jota

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #155 on: December 05, 2018, 10:45:29 AM »
I tried to repair the original front caliper on my 400/4 but it was beyond help with both the fluid union and the bleed nipple snapped in the housing. I bought a pattern caliper from DSS along with a master cylinder repair kit. The master cylinder was an easy rebuild. The hardest part is removing the internal circlip to enable piston removal. You need to buy a cheap pair of long nose or circlip pliers and maybe grind the ends down to fit. Easy job to do though and you keep the original master cylinder with the correct exterior finish, the pattern ones are painted black.

Thanks Laverda - I was planning to purchase a stainless steel piston to replace the slightly pitted/corroded caliper piston (and a new piston seal, too, of course!).  But when I initially removed the caliper, I wasn't able to loosen the fluid union or bleed nipple.  So before I buy anything, I'll see if I can remove those items without damaging anything.  Any advice for this?  I've got plenty of time for penetrating oil, etc - I could even simply drop the whole unit into something to soak, for months if need be.

I'll suppose I'll dismantle the MC as well and see how things look before I buy anything...

Offline taysidedragon

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Re: New (to me!) '77 CB400F - US model
« Reply #156 on: December 05, 2018, 11:18:51 AM »
Try some heat on the offending parts. It may be enough to break the joint. Need to be careful with the heat on the aluminium caliper body of course.
If that fails then soak the body in a container of diesel oil or penetrating oil for a few weeks.
Good luck!
Gareth

1977 CB400F
1965 T100SS

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #157 on: December 05, 2018, 11:24:42 AM »
Try some heat on the offending parts. It may be enough to break the joint. Need to be careful with the heat on the aluminium caliper body of course.
If that fails then soak the body in a container of diesel oil or penetrating oil for a few weeks.
Good luck!

Thanks taysidedragon!  I'll give it a try...

Online Bryanj

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Re: New (to me!) '77 CB400F - US model
« Reply #158 on: December 05, 2018, 12:02:37 PM »
Use one of the disposable cartride plumbers torches and warm the alloy round the fittings till slightly uncomfortable to touch then use a long six sided socket with a tee bar so you are turning evenly not twisting. Never failed to get one out yet. If the pipe union is really bad cut the pipe off flush with the top of the nut and follow same instructions.

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #159 on: December 05, 2018, 12:06:10 PM »
Use one of the disposable cartride plumbers torches and warm the alloy round the fittings till slightly uncomfortable to touch then use a long six sided socket with a tee bar so you are turning evenly not twisting. Never failed to get one out yet. If the pipe union is really bad cut the pipe off flush with the top of the nut and follow same instructions.

Cheers for the tips Bryanj - I don't have a t-bar, but who doesn't like to buy a new tool?!?

Online Bryanj

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Re: New (to me!) '77 CB400F - US model
« Reply #160 on: December 05, 2018, 09:27:55 PM »
I woild say send it to me and i would do it for you but two trips accross the pond would get a bit pricey!!

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #161 on: December 06, 2018, 12:35:37 AM »
I woild say send it to me and i would do it for you but two trips accross the pond would get a bit pricey!!

Yeah - anyway, I'm looking forward to working on this myself.

I must add, though - you're the second member here who has suggested they would do such a job for me if I wanted to send a part.  This is a very kind gesture, and really makes me feel like I've found a proper community of people I'd like to associate with.  So thank you, all, for that!  8)

Online Bryanj

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Re: New (to me!) '77 CB400F - US model
« Reply #162 on: December 06, 2018, 03:45:12 AM »
If it does all gp wrong the caliper is the same on the 500/550 four and the 500 twin so plenty out there.

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #163 on: December 06, 2018, 10:36:34 AM »
If it does all gp wrong the caliper is the same on the 500/550 four and the 500 twin so plenty out there.

Noted, thanks!

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #164 on: December 06, 2018, 11:47:29 PM »
I started work on the brake master cylinder.  Laverda120 says the pattern replacements are painted black, and to keep my OEM one for the original finish.  I find that the finish is a bare metal look on the top, but black around the bottom, sort of 1/2-and-1/2.  Interesting...

The brake lever bushing (that is held in place by the little plate) was like a black sticky paste, rather than rubber; I scooped it out and will replace it during the rebuild.

I could see no sign of the spring clip that holds the piston dust boot on, so I just pulled the dust boot off, in a few pieces.  It took me awhile to even find the clip afterwards, it was rusty and blended in with the rest of the junk remarkably well!  But I eventually found it and removed it; now the c-clip is next.  One end is free to move, but the other is stuck fast; I'll give it a weekend soak with penetrating oil and come back to it.  The piston moves freely, though, so I hope the cylinder/reservoir piece will clean up well...

 

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