Author Topic: New (to me!) '77 CB400F - US model  (Read 38160 times)

Offline Nurse Julie

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Re: New (to me!) '77 CB400F - US model
« Reply #120 on: November 08, 2018, 02:08:12 PM »
Rich (RGB750) made a batch of these.

He may have some left...
Different type to what Rich made on the CB400/4's Steve.....but, if he has made some for the 400, I need one.

Julie - are you running without one?  Have you "shimmed" the filter tight, or come up with some other method of sealing it?
Well Matt, its a bit of a mystery, I did have one but when I was looking in there the other day, its not there now. I can only think I didn't replace it when I put the bike back together, it must be here somewhere. Anyway, a clothes peg wedged down each side, at the back, will do the job just as well I'm sure.
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 billywingnut

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Re: New (to me!) '77 CB400F - US model
« Reply #121 on: November 08, 2018, 09:51:37 PM »
Hi Mattzs,
I bought  a '75 UK model 2 years ago  the tax disk on the bike was for dec 1998. I decided to restore it to ride and not to concourse. I knew it was going to be costly and take time to go thro' it.
Expect to spend £2k. It had to be reliable and safe.
Here's what i did. The carbs, fit new kits and cleaned them, the air box is a pig to get back on. Overhauled the front brake with master cylinder, lines and pads, the disk was ok put on new rear brake shoes.
New wheel bearings back and front, new spokes front and rear, front wheel rim, tyres and inner tubes. Changed the Headstock bearings and fork seals. At this point I decided to strip down the bike completely. It had 34k on the clock. I did a compression test and found no. 2 very low so stripped the engine down and fitted new rings, The cylinder head was a pig to get off as two nuts are open to the  elements these were rusted solid. I replaced the cam chain and cam chain tensioners.
The primary drive chain, chain and sprokets, lapped the valves etc. all the bearings appeared to be in good order but you have to replace all the oil seals, The is an excellent you video on stripping down the engine.  The tank was the wrong colour ( yellow)  but in
good condition so I lined the tank and resprayed it using 2part  rattle cans and it sets hard and looks the part, yours being the US model has the strange filler cap I replaced the petrol filter and fuel lines. The exhaust is the original and like all bright work in serviceable condition. I finally got it on the road in May this year and for safety I took it and had it MOD't which it passed . It's a pleasure to ride, not the fastest bike on the block and you have to rev them.
 I removed the cover from the wiring loom and removed bodges and wiring that didn't belong and checked every connector, you can buy jap connectors so I replaced the lot.
Being a 'mature' rider  at 71 I had the time and patience to sort it. I could easily have spent another £1000 on the engine on a rebore
and replacement head as there is some burnt sections, you have to make a judgment as to how far to go with your restoration. I used only basic tools. Good luck with your 400f 4

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #122 on: November 08, 2018, 10:26:29 PM »
Hi billywingnut -

Wow, thanks for the detailed list!  Compression test, I knew I forgot something!  Oh well, it can wait a few more months.  Still not sure how I'm going to proceed with this - I can't see doing a concours restore, as I don't have the tools, the skills, the time, or the money - hmm, did I miss anything?  The PO says the bike is in good shape, but I'm finding more and more little things that make me wonder why he thinks so.

Another thing I just discovered - the rear fender is badly cracked where one of the upper bolts holds the monstrous tail light.  Wondering about whether to just try to structurally repair these items - seems silly to spend money to renew only a select few bits.

Glad the price was right (free!). More to think about...

Online Laverda Dave

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Re: New (to me!) '77 CB400F - US model
« Reply #123 on: November 08, 2018, 10:47:44 PM »
Matt, do yourself a big favour and buy yourself a 3ltr ultrasonic cleaner. In the UK they cost about £75. Considering it costs £25 per carb for commercial ultrasonic cleaning and there are four of them on a 400/4 buying your own cleaner will pay for itself the first time you use it! You will need to buy a special carb cleaner to add to the water and this costs about £13/litre, you dilute this 1 part to 10 parts water. The added advantage of doing it yourself is you can take the carbs apart in the morning and have them back together in the evening (assuming you have the carb rebuild kits handy). Sending them away to be cleaned just adds time and money when you could be doing something else.
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 #124 on: November 08, 2018, 11:07:41 PM »
Thanks for the advice, Laverda120 - I'll look into that.  I don't have a lot of space, but it looks like a 3-liter unit isn't very big - smaller than 1 cubic foot?  I know a few people who may have such a thing and would be willing to help out, perhaps for free or for the cost of the cleaning fluid, worth asking around...

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #125 on: November 09, 2018, 07:32:30 PM »
I examined the tires more closely.  They're both Dunlop D404, 100/90-18 front, 120/90-18 rear.  Both were made around this time of year - in 2008.  They have a reasonable amount of tread left on them, but they seemed kind of... shiny?  A bit hard?  The rear sidewalls are clear, but the front has some age cracking - so no riding on these babies!  I'll call them "storage tires!"  So, new tires added to the list...

This free motorcycle is getting expensive!  ;D

Offline Nurse Julie

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Re: New (to me!) '77 CB400F - US model
« Reply #126 on: November 09, 2018, 08:19:47 PM »
This free motorcycle is getting expensive!  ;D

Just doing the essentials and making sure it is safe need not cost a fortune Matt. Now, if you want to restore it to concours, well, that's a totally different story 😀😀😁
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 #127 on: November 09, 2018, 09:22:09 PM »
This free motorcycle is getting expensive!  ;D

Just doing the essentials and making sure it is safe need not cost a fortune Matt. Now, if you want to restore it to concours, well, that's a totally different story 😀😀😁

My intention is to get it working safely and well.  So far: New tires, new battery, probably new chain (and possibly sprockets to match) - that's just consumables!  Who knows what we'll find when we start digging in?

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #128 on: November 10, 2018, 02:03:06 PM »
The is an excellent you video on stripping down the engine.

A quick youtube search yields a series of videos posted by "too old to die young" - do you have any specific information about the video you recommend?

Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #129 on: November 11, 2018, 09:16:19 PM »
Getting waaaay ahead of myself here...

I bought a set of old Shoei hard luggage to mount on my Kawasaki W650 - but after getting them in hand and looking at them and trying to sort out how to mount them, I'm not convinced they're right for the bike.  But... maybe for the CB?  At a glance, it looks like the mounting hardware might fit a bit better.  The pie-plate turn signals are in the way and would have to go; the bags have what looks like lights, but they're just lenses with no wiring or sockets of any kind, so that would take some sorting.  Plus, I don't think I would want the bags mounted all the time, so I'd have to have some permanent lights on the bike anyway.

Like I said, waaaay ahead of myself!  ;D

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Offline mattsz

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Re: New (to me!) '77 CB400F - US model
« Reply #130 on: November 16, 2018, 12:43:16 AM »
If I run into specific issues, I'll ask separately, but I'll add general thoughts here...

I've been digging through the archives, and I found a 2017 thread started by Nurse Julie about idle issues - this was before her epic engine rebuild!

http://www.sohc.co.uk/index.php/topic,12977.0.html

In that thread, she said:

Quote
as Trig said before, the engine does need some internal work done as she has oil vapour in the airbox.

So I'm wondering - does oil vapo(u)r in the airbox always suggest the need for engine work?  And, what does it look like?  In my bike the little breather foam filter beneath the air filter is disintegrating, and is quite oil-soaked.  The air box around it is damp with oil, as is the bottom of the primary air filter.  It this an indicator that internal engine work is definitely in my future?

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Offline taysidedragon

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Re: New (to me!) '77 CB400F - US model
« Reply #131 on: November 16, 2018, 11:42:11 AM »
It's hard to be sure because you don't know how long it has been since the oil trap was last cleaned out. It could have built up over a long period of time.
If it built up quickly it could indicate engine wear, probably piston rings/rebore or valve wear.
Gareth

1977 CB400F
1965 T100SS

Offline zebedee85

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Re: New (to me!) '77 CB400F - US model
« Reply #132 on: November 16, 2018, 12:04:59 PM »
this can happen if the oil is ever overfilled as well.

if your air box doesn't fill with oil quickly, you don't encounter blue smoke, your cam chain can be adjusted via an non-seized adjuster mechanism and any head oil weeps remain insignificant I'd leave it alone until it was worth pulling apart.

Offline Nurse Julie

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Re: New (to me!) '77 CB400F - US model
« Reply #133 on: November 16, 2018, 03:41:33 PM »
No point thinking about engine rebuilds until you know how long the trap and air filter box hasn't been cleaned for. Mine filled with oil vapour quite quickly due to internal damage the engine had sustained previously causing raised crank pressure. Give it all a good clean out, fit new foam (make your own out of a kitchen foam scratchy thingy) and air filter,ride it and observe. Even if there is nothing particularly wrong with your engine, its an old engine so internal wear is to be expected but oil vapour doesn't give conclusive evidence that there is a problem that needs immediate attention. As has already been pointed out a combination of oil vapour and blue smoke would give more of an indication that there may be a problem.
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 #134 on: November 16, 2018, 04:07:34 PM »
Thanks all!  I wish I'd paid more attention when I rode it 3 years ago - it has only a few hundred miles more since then.  But I wouldn't have known what to pay attention to anyway, as far as noises and such on these engines go.  Blue smoke is universal, however!  I don't recall any at the time...

I won't worry about it now, just a fact-finding mission, if you will...

 

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