Author Topic: My 1975 CB400F US  (Read 8112 times)

Offline Laverda Dave

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Re: My 1975 CB400F US
« Reply #15 on: September 01, 2016, 10:42:36 PM »
Well done on getting to the stage you have done given the time constraints.
I am in a similar place with my own 'project 400' and hope to finish in the next couple of weeks.
The main issues I've had are pattern parts that don't fit, have been incorrectly described or even genuine parts that have been superseded by poorer quality 'genuine' parts.
Having said that if it wasn't for the great people on this fantastic forum offering guidance and knowledge I wouldn't be as far as I am now with the build!
I hope you finish yours soon and the sun shines on the first ride, good luck and keep going, it will be worth it  :)
Dave
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 kent400

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Re: My 1975 CB400F US
« Reply #16 on: September 02, 2016, 08:06:56 AM »
Really good job done there Peter, far easier restoration than the model A Ford you have no doubt. I seem to remember your  speedo was quite rusty inside due to the body damage having distorted the rubber seal. Water ingress probably made worse by use of a power washer with some enthusiasm at some stage.

Interestingly another speedo turned up last week that's rusty inside caused by a very poor substitute for the trip grommet which allowed the water ingress. Speaking to the owner he's owned it from new and it's now covered 100390. That's right one hundred, thirty nine thousand miles. It had a rebore at 70k miles but the bottom end hasn't been touched. Three cam chain replacements. It seems however he's been changed the oil and filter every 1000 miles. He's not a member on here, too old for these computers apparently at 58!

The speedo mechanism was still serviceable once all the rust from the corroded inner body was removed.     

Offline mike the bike

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Re: My 1975 CB400F US
« Reply #17 on: September 02, 2016, 08:35:20 AM »
Thanks for sharing.  I enjoyed reading it and studying the pics, great job.  It's an unusual beastie this side of the pond with its larger yankee back light.  When is it on the road or is it already?
+1 on the HT caps, best get a set of NGK ones, 1,4 are different from 2,3.
Where's that 10mm socket got to?

Offline petermigreen

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Re: My 1975 CB400F US
« Reply #18 on: September 02, 2016, 11:46:44 AM »
Thank you for all the kind positive comments. Don't worry, new plug caps are on order.

Sheesh, you don't miss much do you!!

By the way, I did replace the horrendous American spec handlebars, they just look so wrong in my opinion.

Mike, bike not on road yet but imminent.

Offline MarkCR750

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Re: My 1975 CB400F US
« Reply #19 on: September 02, 2016, 07:59:45 PM »
Great looking bike, I had one 30years ago , the current owner won't sell it back to me, grr!, I see they featured one on last night classic TT program, that must say something about them, anyway nice work!.
Suzuki GT250A (Nostalgia)
1977 K7 CR750 (lookalike, what of I’m not sure)
Ducati 900SS (Soul & Speed)
Ducati M900 Monster (Handling & character)
Thruxton 1200 (suits me)
James Captain 197 (pure adrenaline, i.e. no brakes!)
"Eff yir gitten awvestear yir gooin te farst"
Sir J.Stewart.

Offline petermigreen

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Re: My 1975 CB400F US
« Reply #20 on: September 07, 2016, 10:08:03 PM »
I received a big box of parts this week so have made some progress but I still feel a long way off just yet  :'(

Managed to get all the cables and pipes hooked up to the carbs and straight away noticed petrol overflowing out of 2 and 3 so out with the carbs again and replaced the float valves and re-set float heights. Felt prudent to test on the bench before refitting.

[ Guests cannot view attachments ]

So back on with the bowls and back in the bike, after spending what seemed like an hour trying to 'encourage' the float bowl gaskets back into their recess!! That's like some kinda fricking Chinese puzzle!! Happily though carbs are no longer overflowing.

I'm now in the situation where the engine starts fine and runs but I'm way off on the carb adjustments and I'm even struggling to set a decent idle as the revs seem to rise and fall randomly. Very rich judging by the plugs and smoke coming out of the silencer also.

I have bought some vacuum gauges but am a long way off getting to that fine tuning stage.

Also, the tacho seems to glide up and down rather than follow the true engine revs if that makes sense. Not sure this is correct but it's a brand new cable and it's free so a bit confused about this.

Any carb tuning experts out there??

In addition to the carb woes, I've got no clutch either, that is to say that I don't think the mechanism is making contact with the clutch as there is no resistance at the lever whatsoever.

Also received notice that the VJMC honda dating officer has received my application so the registration process is in motion.
« Last Edit: September 07, 2016, 10:09:54 PM by petermigreen »

Offline mike the bike

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Re: My 1975 CB400F US
« Reply #21 on: September 08, 2016, 08:08:14 AM »
There's a coarse clurch adjustment under the triangular plate on the clutch cover..  It sounds like that needs tweaking.
Where's that 10mm socket got to?

Offline petermigreen

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Re: My 1975 CB400F US
« Reply #22 on: September 14, 2016, 09:47:16 PM »
Update -
Been a bit of an eventful week and I had to walk away for a few days to gather my thoughts.
I've had the carb bank back off the bike and whilst on the bench the fast idle cam fell off its spindle! Happens to be lucky as it made me realise why my choke mechanism wasn't behaving as it should.
As I was at the VJMC day at Ace Cafe on Sunday I took the opportunity to get a good look at the mechanism on a tidy 400/4 on the VJMC club stand and got a few photos for reference.

So choke mechanism repaired, carbs re-stripped and rebuilt with all new jets, O rings etc. and all datums reset. Got them back on the bike last night and balanced tonight and bike now singing like a bird. Beautiful.

With the engine tuned I decided to drain the oil and remove clutch cover so I could solve the lack of clutch issue. Turns out the course adjustment screw was corroded into the mechanism which is why I couldn't adjust it in the usual way. That's now cleaned and fettled and I now have the clutch back in action.

Very satisfying as all the major problems are now overcome I have an MOT booked for Saturday week and my dating letter is now with me. So after MOT I'll be able to send off to the DVLA for my historic bike age related registration.

You never know I may just get a ride or two in before the leaves fall. 8)

Offline petermigreen

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Re: My 1975 CB400F US
« Reply #23 on: September 15, 2016, 08:40:39 PM »
Clutch sorted so couldn't resist a quick test run to make sure it all checks out.
https://www.youtube.com/watch?v=rXdxi6wLJEY
Very pleased.

(Yes I did miss 2nd gear :-[ cos I was just so excited ;D)
« Last Edit: September 15, 2016, 08:54:18 PM by petermigreen »

Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
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Re: My 1975 CB400F US
« Reply #24 on: September 15, 2016, 08:57:11 PM »
How exciting and I see you have one of those invisible number plates  ;D ;D ;D
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 petermigreen

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Re: My 1975 CB400F US
« Reply #25 on: September 15, 2016, 09:00:00 PM »
How exciting and I see you have one of those invisible number plates  ;D ;D ;D
"Must have fallen off Officer!" or 'It's in the post, honest"  ;D 8)

Offline Nurse Julie

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Re: My 1975 CB400F US
« Reply #26 on: September 15, 2016, 09:01:37 PM »
 ;D ;D ;D ;D
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 mike the bike

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Re: My 1975 CB400F US
« Reply #27 on: September 15, 2016, 09:35:24 PM »
I'm after one of those pixellated ones you see on the telly
Where's that 10mm socket got to?

Offline petermigreen

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Re: My 1975 CB400F US
« Reply #28 on: September 15, 2016, 09:46:39 PM »
I'm after one of those pixellated ones you see on the telly
Mike, buy yourself a black marker pen and a grey marker pen, you could make your own.

Offline kent400

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Re: My 1975 CB400F US
« Reply #29 on: September 15, 2016, 10:19:40 PM »
Absolutely great Peter and so was the following you tube clip. Now that model A was really a challenge a real credit to you.

 

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