Honda-SOHC

SOHC.co.uk Forums => Project Board => Topic started by: Coppertop1234 on January 25, 2026, 04:20:56 PM

Title: Keiths 400/4
Post by: Coppertop1234 on January 25, 2026, 04:20:56 PM
Hi all just purchased the 400/4 as a last project bike .
The bike has been a previous 87 year old gentlemen's project in 2019
He rebuilt the engine and restored the bike to its present standard.
A good starting point for a mainly cosmetic restoration.

I like bikes to be original or as near as so this will be my aim

Bits that stand out
Forks off a superdream i think - replacements on order
Brakes off  a superdream  (no pressure switch) - replacements on order
Wheels same again - new tyres though - i have 2 spoked hubs sort this one later with new rims and spokes
Chain Guard - chrome gone painted black - livable for now
Paint work - Spring job back to correct red and decals
Frame painted  - livable for now
Wiring all works taped up so maybe new harness
Chrome work on indicators shot so replacements
New chain and spockets - Bonus
Battery dead - new battery
Exhaust none standard - replace to oem replica on order - need downpipes and collits
New seat  - Bonus
Clocks work fine just cosmetics

Bike starts runs / stops and goes through gears fine no bad engine noises or immediate issues.

Tidy little project to get another 400 back to the best it could be within reason of course.

Pic of my last 2 bikes i restored  CB750 Fi and CB250 Dream which both were wrecks prior.

a few of new project







Title: Re: Keiths 400/4
Post by: Ken4004 on January 26, 2026, 03:25:30 PM
Looks nice , do you mind me asking how much you paid for the bike ?
Title: Re: Keiths 400/4
Post by: Coppertop1234 on January 26, 2026, 04:43:52 PM
not at all Ken
 I paid the asking price of 2395 (he wouldnt drop in price)
I paid because the engine had been rebuilt and it also had a second rebuilt engine with it along with other bits and bobs
also it looked a half decent resto to continue.
Title: Re: Keiths 400/4
Post by: Coppertop1234 on January 26, 2026, 05:00:14 PM
I think the correct colour should be Candy Antares Red
I don't want to set off a colour argument, but the burgundy red is my preference
Probably because all my 400's and 750's were burgundy

Parts on order to start
Forks and axle retainers
Brake pressure switch
Complete new front brake  and fittings
Dearer bits from DS
Full exhaust system with fitments
New front brake lines
Side grab bar

I am glad the wife doesnt use the forum. :) :)

and still some to get of course




Title: Re: Keiths 400/4
Post by: Ken4004 on January 26, 2026, 05:07:16 PM
That sounds like a fair price because it looks good in the photos, My bike was originally candy red but I fancy the yellow so it’s been re sprayed.

On my last CB400 I had it sprayed Candy and it did look amazing but as I remember the paint was really expensive but worth it for the finished product.
Title: Re: Keiths 400/4
Post by: Coppertop1234 on January 26, 2026, 05:13:22 PM
i usually do my own with rattle cans and it always comes out really well - not to put spec on it

Last time on the 750F1 i used BMW candy red which was so close you couldnt tell the difference
Title: Re: Keiths 400/4
Post by: Coppertop1234 on January 28, 2026, 12:39:45 PM
Bits are starting to land :) :)

New Caliper & pressure switch for brake line landed

DS stuff dispatched that was quick
Forks arriving later today

So time to start tinkering
all the old forks calipers exhaust etc will be going on ebay unless anyone here is interested
Title: Re: Keiths 400/4
Post by: Coppertop1234 on January 28, 2026, 03:56:09 PM
Well that didnt go to plan

Old forks are 31mm were on bike
New Forks 33mm (bottoms fine legs pitted)

Yolk 31mm so presume this is also of a superdream - but obviously dont fit

New forks are identified for a 400/4 from seller and manual says 33mm so guess these are right bottoms for bike
old forks legs are also longer than new ones

I only wanted to change fork bottoms but  - plan B

Use new fork bottoms 33mm - got these
get 2 new fork legs 33mm - available on ebay
get new top and bottom yolk 33mm and bearings to suit - (hahahaha cant seem to find these)

or open to other models/ options that would take standard stock fittings brakes mudguard etc

even though of a frame with decent front end on it as an option

Title: Re: Keiths 400/4
Post by: Bryanj on January 28, 2026, 06:12:46 PM
Just checked on cms and lower G5 yoke is same but top is different
Title: Re: Keiths 400/4
Post by: Coppertop1234 on January 28, 2026, 07:54:46 PM
Just found a bottom and top yoke they say for 400/4 f 1977
we will see when they land.
Time to strip top end down clean and refurb ready to rebuild all being well.
ordered new head bearings in anticipation of correct fit.
Title: Re: Keiths 400/4
Post by: Coppertop1234 on January 29, 2026, 01:26:45 PM
Few more bits landed
Exhaust looks nice enough for a replica
(glad he came when missus was out )
I will post pics as we progress - hopefully.
Title: Re: Keiths 400/4
Post by: Ken4004 on January 29, 2026, 02:49:46 PM
Where did you get the exhaust from looks quite nice, is it single wall thickness on the down pipes, I have heard that some of the replicas because of the reduced wall thickness they can discolour when heated up .
This is not a bad thing infect I like the look of the different colour bands , reminds me of when I started my apprenticeship where we heat treated chisels and punches a few years ago now .
Title: Re: Keiths 400/4
Post by: Coppertop1234 on January 29, 2026, 03:19:52 PM
Yup not like a good bit of tempering Ken remember it well from my training days in the early 70's and the forge in metal work classes. Schools would have a dicky fit it they had woodwork and metalwork as classes nowadays.

Exhaust is a DS replica, I dont know about thickness just packed it away until i am ready

just hope the new yolks are right size for forks. the super dream forks i took out were about 2 inch longer than these I have just bought, but the said they were for a 400/4.

its all trial and error ,hopefully not too much error though.
Title: Re: Keiths 400/4
Post by: Coppertop1234 on January 29, 2026, 05:13:53 PM
Front end stripped out ready

Bikes in background are my sons

Chinese 80cc monkey bike

Harley 1250

(i think he gets more fun on the monkey bike )
Title: Re: Keiths 400/4
Post by: Bryanj on January 29, 2026, 05:22:40 PM
Having sold both and pdi'd the first 1340 in Gloucestershire i can guarantee he has more fun on the monkey bike, and i bet its more reliable
Title: Re: Keiths 400/4
Post by: Coppertop1234 on January 30, 2026, 02:40:59 PM
Would someone confirm for me the front forks are 33mm ? or have i lost the plot already

On the bike were 31mm presumably off a superdream

I ordered from ebay forks,  top and bottom yolk all supposed to be for 1977 400/4

top yolk came 31mm  - forks from same place 33mm ??

I just sent them back if they cant sell matching kit what's the quality like.

still waiting for bottom yolk hopefully 33mm and what i need if i am correct.

now looking for top yolk and forks again.
Title: Re: Keiths 400/4
Post by: Bryanj on January 30, 2026, 03:08:32 PM
Look at cmsnl parts list , size is usually quoted
Title: Re: Keiths 400/4
Post by: Coppertop1234 on January 30, 2026, 04:18:37 PM
just found complete front end only 1 slight problem

they are in italy - hope they are not left hand drive

delivery in 2 to 4 weeks no rush plenty to do to keep me occupied.
Title: Re: Keiths 400/4
Post by: taysidedragon on January 30, 2026, 11:43:27 PM
Would someone confirm for me the front forks are 33mm ? or have i lost the plot already

On the bike were 31mm presumably off a superdream

I ordered from ebay forks,  top and bottom yolk all supposed to be for 1977 400/4

top yolk came 31mm  - forks from same place 33mm ??

I just sent them back if they cant sell matching kit what's the quality like.

still waiting for bottom yolk hopefully 33mm and what i need if i am correct.

now looking for top yolk and forks again.

400Four are definitely 33mm.
Title: Re: Keiths 400/4
Post by: Coppertop1234 on January 31, 2026, 12:29:43 PM
cheers for that i thought they were 33 mm,but nice to have it confirmed
 :)
Title: Re: Keiths 400/4
Post by: Bryanj on January 31, 2026, 03:50:50 PM
I think your Superdream confusion is 250 were 31 and single disc whilst 400 was 33 and twin disc
Title: Re: Keiths 400/4
Post by: Coppertop1234 on February 01, 2026, 09:21:29 AM
Thought so

just having a debate with a no return on ebay who sent me a 31mm yolk, he said it is of a 400/4 and wants me to explain why they dont fit.

I sent him info on people used the superdream forks on 400's as a replacement and obviously the one he is stripping had had this  conversion to 31mm which are not correct spec for bike which i required.

Waiting for further response on return,but buyer protection should cover it as the are not as described.
Title: Re: Keiths 400/4
Post by: Coppertop1234 on February 05, 2026, 12:37:18 PM
You couldnt write it
just speaking to a motorcycle shop friend and he is just breaking a 400/4 with a complete front end on it.
aw well you have to grasp the best option at the time , which was italy parts option for me.

Title: Re: Keiths 400/4
Post by: Coppertop1234 on February 07, 2026, 06:22:00 PM
Front forks landed and they are just as they should be no pitting well pleased.

stripped and cleaned then fitted them ,then new brake line and pressure switch Stage 1 done  for now

Fitted DS replica exhaust   No major issues

Removed all the old pvc tape off the harness and replaced with heatproof  / waterproof fabric tape - looks a lot tidier

Rewired and yes she fired up exhaust sounds nice, but carbs are well out - job for a bit later.

just tried an old 400 wheel in forks and the axle that was on bike with comstars is too big and speed drive is not compatible either, no surprise there

glad i tried them before i started stripping old wheel back to hub.

A good days progress today, well pleased with results




Title: Re: Keiths 400/4
Post by: Coppertop1234 on February 10, 2026, 01:20:00 PM
Just mounted horn and tacho guide only to find horn then didnt work .

after investigation it would seem a previous owner had cut the wires in the switchgear and taped them back together.

Not a great job of doing connections horn switch was araldited in place so in short switch gear needed replacing to do the job right.

The switch gear didnt seem to fit quite right either with a visible gap all way round the joint, so is probably also of a different model.

Cleaned and tidied rear light mount while playing.

Its all part of the fun finding whats right and whats not.


Title: Re: Keiths 400/4
Post by: Coppertop1234 on February 11, 2026, 03:42:30 PM
New switch gears arrived and fitted

The quality of the DS replica seems decent and looks as good as originals

Slight disappointment the wiring is not matching to original - ok for me with the matching colour guide provided, but may be a problem for someone else at a future stage down the line.

I will make note on DS invoice of colour matching wires to keep in file.
Title: Re: Keiths 400/4
Post by: mickwinf on February 11, 2026, 04:26:47 PM
the thing that bugs me is costs the same to use the proper colours, so why use any others?
Title: Re: Keiths 400/4
Post by: Coppertop1234 on February 16, 2026, 05:24:28 PM
Hi would some one be able to post me a few pics of horn mount from both sides.

Better to ask than bodge about trying this and that.
I made the previous mounts which fit and have the horn facing forwards under tank.

I have now got an original horn and fittings, but unsure if i have them all and how they go?
Got horn working and cleaned up, but do i have everything

pics of what i have.

I think
Short wire clip if rh side as a cable retainer for throttle cables?
Angled bracket is Left hand side and has a rubber cable retainer like battery box one fitted from frame to bracket?
Horn mounts on rh side flat to frame  with fixed bracket 2 holes at top - no pic?
Where does taco retaining wire fit ?

cheers
keith


Title: Re: Keiths 400/4
Post by: exvalvesetdabbler on February 16, 2026, 08:05:55 PM
I think the forward facing horn was a requirement in some European countries. Netherlands being one.

The horn bracket goes on the right hand side, and on mine the cable tidy wire piece goes on the front mounting bolt.

The bracket for the rubber strap on the left, there should be a bit on the frame for the other end of the strap .

Don't bother until your done with plugs and tappets. It just gets in the way.

Regards
Dave.
Title: Re: Keiths 400/4
Post by: exvalvesetdabbler on February 16, 2026, 08:10:19 PM
The dealer setup manual will show you the cable routes.  It's in Ash's Dropbox.

The tacho cable just dangles,  clutch and throttle go through the clip.

Regards
Dave
Title: Re: Keiths 400/4
Post by: Coppertop1234 on February 17, 2026, 10:24:17 AM
Found the set up manual and diagrams thank you Dave

Helpful document cheers Ash.

Cables now routed as should be and all ok.

Horn located correctly and working fine

on to next job carbs clean and refurb

(well my son will do it really beyond my eyesight these days)
Title: Re: Keiths 400/4
Post by: Bryanj on February 17, 2026, 01:19:20 PM
Nurse Julie for O ring kits and clean all the original internals, ultrasonic more or less esential
Title: Re: Keiths 400/4
Post by: Coppertop1234 on February 17, 2026, 03:35:55 PM
Ultra sonic and cleaning agent ordered

carbs off ready to strip Pic 1

Most of black engine paint removed. (why would you paint it black)

Spare carbs from a recently acquired donor bike. Pic 2 :) :)

So we presently have 3 rebuilds on the go

Mine  and my sons other 2




Title: Re: Keiths 400/4
Post by: Coppertop1234 on February 22, 2026, 05:12:21 PM
Carbs stripped and rebuilt by my son Keith Jnr.

(I do the pointing, He does the seeing and skinning knuckles. Glad he also likes motorbikes)

First time he has done carbs though -  Utrasonic leaned and new jets etc

Well pleased with results -back on bike all working fine

Also fitted new electronic ignition from DS straight enough replacement for points
Working on wheels \now new rim ,spokes and bearings just need new retainers and removal tools for retainers

front retainer has been chaveld so got it out with a bit of old school hammer and chisel
New bearings fitted once i have retainer i can start to relace rim.

Bike is coming together bit at a time


Title: Re: Keiths 400/4
Post by: McCabe-Thiele (Ted) on February 22, 2026, 05:44:37 PM
I had a set of Keyster repair kits as per your photo, they came with my bike, they were purchased some 10-15 years ago by the PO.

The bike runs great on them despite many reporting  that the original brass wear is better cleaned & kept.
Title: Re: Keiths 400/4
Post by: Coppertop1234 on March 09, 2026, 06:10:45 PM
Wheel rebuilt with new rim spokes and bearings sent to local shop for trueing, tube and tyre.

After about 14 incorrect attempts to get lacing pattern right ,on 15th attempt it all just fell into place. I Hope!!

Thought of trueing it myself, but to be honest eye sights not best so let shop do it .

Front Mudguard sent for rechroming ,so only front brake to fit and front end is finally sorted.

Not doing brake till last off as i don't want it to start to seize just for the sake of fitting it to early.

Next job 

New indicators to fit a bit of bling as old ones are original but very pitted.
Then onto back wheel to do same refurb again.

loving messing about again nothing too drastic just tinkering and sorting out whats not right.

Cant wait for better weather to start on paintwork and make it look like a 400 should. :)





Title: Re: Keiths 400/4
Post by: Coppertop1234 on March 13, 2026, 04:28:13 AM
Finally removed last of black paint from engine block.

Repainted with heat resistant paint to tidy up and look more like it should.

Just got to remove studs and clean paint off them- one at a time

little bit of polishing to alloy covers to make them stand out a bit.

Fitted rear indicators, just got to tidy wires a bit and replace old cable clip

sorry for messy workspace spaners and crap all over at moment ,think i need to tidy up.
Title: Re: Keiths 400/4
Post by: Laverda Dave on March 13, 2026, 04:28:14 PM
Well done Keith, its getting there.
When is the maiden voyge planned?
Title: Re: Keiths 400/4
Post by: Coppertop1234 on March 13, 2026, 05:39:08 PM
Hoping to do the Distinguish Gentleman's Ride in May with both my sons.

But may get on road end of April  ;D

Yes I think its getting there and starting to look like it should.

its such fun only a biker could understand (and a considerate wife of course )

Title: Re: Keiths 400/4
Post by: Coppertop1234 on March 15, 2026, 12:36:50 PM
Rear Hub stripped and bearings out ready for wheel re build.

waiting for front to return this week trued with new tyre and tube fitted.

Son popped over today to balance carbs. it was a pain No 3 just wouldn't move.

checked valves all ok, had carbs off bench set them, checked all intake rubbers, rebuilt

last thing checked vacuum pipes and yes you guessed it blockage on No 3.

well could have been worse and passed the morning on nice.

Engine sound nice with the ds replica exhaust, and ticks over with no fluctuation, bit of echoing from garage, but don't think i will have any issues with the previous owners rebuild.

Son took spare engine to his to make a start on refit into his bike. it was rebuilt i n 2019 and never fitted so first thing is it free or siezed as it was dry stored. Plenty of penetrating into bores before we try to turn it over i think.
Title: Re: Keiths 400/4
Post by: Coppertop1234 on March 30, 2026, 05:18:42 PM
Just found some decals i had one is for exhaust muffler

Where was this placed on the bike? Swinging Arm?

Advice appreciated

ta

Keith
Title: Re: Keiths 400/4
Post by: Bryanj on March 30, 2026, 05:34:55 PM
Swing arm by sjlencer and readable
Title: Re: Keiths 400/4
Post by: Coppertop1234 on March 30, 2026, 05:44:42 PM
Cheers thought it would melt on muffler ;D

still waiting for wheels to return hopefully this week

Paint and tank decals on order.

Bike No 2 now up and running also

We spent the weekend on it got engine in wired up and all fired up ok so we may have 2 more 400s back on the road soon.
Title: Re: Keiths 400/4
Post by: Coppertop1234 on April 17, 2026, 05:15:19 PM
Tank and panels sprayed and decals fitted ready to laquer  after we put  preserve nature sticker on
Title: Re: Keiths 400/4
Post by: Coppertop1234 on April 17, 2026, 05:18:57 PM
Tank before
Title: Re: Keiths 400/4
Post by: Coppertop1234 on April 17, 2026, 05:23:47 PM
Total cost of around £120.00
Title: Re: Keiths 400/4
Post by: Coppertop1234 on April 17, 2026, 05:35:50 PM
Preserve nature fitted
Title: Re: Keiths 400/4
Post by: Oddjob on April 17, 2026, 05:38:16 PM
Is it me or does both the hinge and catch brackets look twisted?
Title: Re: Keiths 400/4
Post by: Coppertop1234 on April 17, 2026, 05:42:08 PM
Think its the angle of the dangle on how I took pic
Title: Re: Keiths 400/4
Post by: Coppertop1234 on April 24, 2026, 06:23:02 AM
Paint work complete just a bit of cutting back to do.
Only waiting for rechromed front mudguard and we're off on a road test
Keith jnr is starting on 750 fi and his Ruby red f0 while weather is good
Title: Re: Keiths 400/4
Post by: taysidedragon on April 24, 2026, 12:33:44 PM
Nice!
Title: Re: Keiths 400/4
Post by: Coppertop1234 on April 24, 2026, 02:26:39 PM
Thank you not looking too far off a decent job for novices
Title: Re: Keiths 400/4
Post by: K2-K6 on April 24, 2026, 03:08:36 PM
Some very good work, and results there.

It surprises me the different overall appearance of 400 Four whether wearing the original "flat" colour in early models in comparison to the later metallic like this.

Seems to impart a different outlook/market just from that small shift on essentially the same bike.
Title: Re: Keiths 400/4
Post by: taysidedragon on April 24, 2026, 03:29:04 PM
Keith, it's probably just a trial fit, but if not, the side panel is not fully located and pushed in at the bottom fixing. You don't want to lose those freshly painted panels!
Title: Re: Keiths 400/4
Post by: Coppertop1234 on April 24, 2026, 03:31:28 PM
Cheers Gareth

Yes your right trial fit waiting for paint to harden fully before i put the rubber bungs in

Bought some replacements and they are solid, even in hot water so not for fitting today
Title: Re: Keiths 400/4
Post by: Coppertop1234 on April 24, 2026, 04:00:38 PM
Ruby Red Tank painted up so we are getting there