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SOHC.co.uk Forums => CB350/400 => Topic started by: waffey on January 03, 2020, 02:46:52 PM

Title: Engine Strip - I'm nervous
Post by: waffey on January 03, 2020, 02:46:52 PM
Hi All,

so i'm finally getting on with the Honda CB400 1977. I've asked many questions on here so far with plenty more to come.

I'll try and bring you all up to speed.

(1) ]Bike has been stripped down an now lives in boxes.

(2) I've started to refurbish the clocks but awaiting to make a decision on the clock faces, that is either to get vinyl over layor leave them as is. I'll probably go with 'leave as is'

(3) The frame is due to go to the powder coaters next week along with the yokes and some other bits as recommend in a previous post.

(4) I'm stripping the engine at the moment (Yet to split the crankcases). This is where I'm going to struggle. I've noticed the following things
(4a) Some of the fins on the oil filter are damaged.
(4b) The sump pan has been welded around the sump plug.
(4c) The oil pick up filter has metal pieces in it. It was also covered in thick gunge almost like gearbox oil.
(4d) The pistons and head are covered in thick carbon.
(4e) Removing the barrel some of the piston rings fell out (they were in two pieces).
(4f) The cam tensioner adjuster has been broken.
(4g) The barrels look ok but I need to measure them yet.
(4h) The pistons look ok but I need to measure them.

So my current  plan once I've split the crankcases are: Check crank bearing shells (plastic gauge them), measure barrel and pistons firstly for wear and to understand if the engine has standard pistons. Then get all the cases cleaned and checked. Then my plan is to get the barrels honed / rebored if required with new pistons ect, new bearings etc and then start to rebuild the engine. I want the engine in  the frame as I think this will be the easiest way to build the bike back up.

Please feel free to comment and give me guidance.

Is there anyone nearby to Plymouth that maybe able to help me / guide me?
[attach=1]

Title: Re: Engine Strip - I'm nervous
Post by: waffey on January 03, 2020, 02:54:36 PM
and some more pictures
Title: Re: Engine Strip - I'm nervous
Post by: Trigger on January 03, 2020, 03:18:09 PM
Clocks send to Peter or put new faces on.

Focus on the bottom end as, that is the first part you want in the frame. If a ring or two has broken then there should be marks in the bores. 0.50 piston kits are cheap and get them rebored and matched by someone that knows Japanese engines.

The bottom end needs a close inspection and replace cam chain, primary chain, primary rubbers and seal kit as STD if the engine is high mileage, you don't want to be going in there again. 
Title: Re: Engine Strip - I'm nervous
Post by: waffey on January 03, 2020, 04:33:30 PM
Thanks trigger.

No score marks on barrels but the engine sat for a long time unused (plus 15 years). I think its 48,000 miles on the clock.

Do I really need to replace the primary chain as a matter of course?

There is a local machine shop nearby which I will approach for the rebore.
Title: Re: Engine Strip - I'm nervous
Post by: Nurse Julie on January 03, 2020, 04:38:14 PM
Fully investigate where the metal debris has come from in the sump / oil strainer. Is it the broken rings, or mushed up gearbox components etc. If metal debris has been going around the engine, all bearing surfaces / cam shaft / bores etc may have sustained major damage and maybe beyond repair. Good luck with everything and replace the cam chain and guides and hyvo primary etc. At 48k, they will be on their last legs, if not beyond.
Title: Re: Engine Strip - I'm nervous
Post by: Bryanj on January 03, 2020, 05:55:12 PM
Yes it is necessary to replace primary chain and cush rubbers
Title: Re: Engine Strip - I'm nervous
Post by: PatM on January 03, 2020, 05:57:25 PM
Trigger and Julie know their stuff as they have done all this before.
Just to pick up on one of your points which I think i can answer-

(4c) The oil pick up filter has metal pieces in it. It was also covered in thick gunge almost like gearbox oil.

When I rebuilt mine 9 years ago . I bought it as a sorry-state non-runner. Id not had one since the early 90's.
I popped off the sump and found the same as you-it was aluminium gunk and bits all over the strainer, so I cleared it off and promptly put it all back together without to much consideration as to where it has come from. I was hoping it was general wear and or sloppy oil-changes.

I was chatting on here to Julie about cam-chain adjustment as I went to 'adjust' mine and undoing the adjuster made little difference-even though its a stainless steel bolt and nut. The penny dropped-my lower cam-chain horse-shoe has seized.
 Now, Julie told me Id have to strip the motor to replace it-which is correct-but I read about this somewhere and although its not a permanent fix (Julie said its a bodge..) You can insert a long thin drift down the throat of the chamber-accessed via the large cap thats above the adjuster- and 'tap' the drift. This, in my case moved the lower horse-shoe and shut the cam-chain up. The metal on the strainer was non-metallic and caused by the chain rubbing/eroding the throat of the chamber.
Im actually and engineer!-but I saw little benefit at the time stripping the whole motor-I retire in a few years, have too many other bikes to maintain and cars...Ill save all that for then-its not as if the 400/4 gets much use-used in thrice in 2019- and I know what the cam-chain sounds like when its loose!
I also plan to do the head/valves but if Im going to remove the motor and start dismantling it-Ill do it once!
Ive rebuilt these motors before back in the early 80's and I know how easy bolts strip or heads snap off- my bikes running perfectly well and Im not into causing myself a load of grief, neither have I the spare cash to instantly resolve it! Back in the 80's you can pick up a running 400 motor for £50- no problem- the breakers were full of them in London area.

Title: Re: Engine Strip - I'm nervous
Post by: waffey on January 03, 2020, 10:21:16 PM
Thanks PatM,

i'm hoping my 'bits' in the strainer are the same as yours. Hopefully i'll have the crank case split this weekend.

I'll post some more pictures then. The frame is booked in for the 10
Title: Re: Engine Strip - I'm nervous
Post by: Bryanj on January 03, 2020, 11:09:32 PM
Considering you had broken rings i would not even bother measuring but buy oversize and rebore, chances are that the broken rings have worn the ring grooves in the pistons.
Title: Re: Engine Strip - I'm nervous
Post by: Trigger on January 04, 2020, 09:07:24 AM
As Bryan has already said, not worth the trouble with the pistons , a engineering shop can charge around £45 just to measure up and then tell you that you then need a rebore. You can get a good oversize set from Japan for about £110 including post. Get a good engineer to rebore at a piston to bore clearance of one thou , if anyone tells you that this is too tight, walk away as, they don't know what they are doing.

If the sump pan is leaking from the drain bolt, look for a good secondhand one that has not been welded. Never torque a sump bolt more than 20 ftlb on these old girls or they will crack the pan  ;)
Title: Re: Engine Strip - I'm nervous
Post by: waffey on January 04, 2020, 10:23:46 AM
thanks trigger. advice taken. hopefully, strip the crank case today then i'll post some more pictures

something like this as a piston set? https://www.ebay.co.uk/itm/264088297262
Title: Re: Engine Strip - I'm nervous
Post by: Trigger on January 04, 2020, 10:33:26 AM
Yep, that piston set will do  ;)
Just remember to mark the shells as to were they come from, if mixed then you will need a whole new set.
Title: Re: Engine Strip - I'm nervous
Post by: Oggie400F on January 04, 2020, 01:54:54 PM
As Bryan has already said, not worth the trouble with the pistons , a engineering shop can charge around £45 just to measure up and then tell you that you then need a rebore. You can get a good oversize set from Japan for about £110 including post. Get a good engineer to rebore at a piston to bore clearance of one thou , if anyone tells you that this is too tight, walk away as, they don't know what they are doing.

If the sump pan is leaking from the drain bolt, look for a good secondhand one that has not been welded. Never torque a sump bolt more than 20 ftlb on these old girls or they will crack the pan  ;)

Hi Trigger
Are the piston sets from Japan via Cruzinimage or someone else?
Title: Re: Engine Strip - I'm nervous
Post by: waffey on January 04, 2020, 03:57:55 PM
Hi,

crank case split, I cant find any damaged teeth or casing. must o been a bit of? a piston ring, alloy from the welded sump or who knows!!

Title: Re: Engine Strip - I'm nervous
Post by: waffey on January 04, 2020, 04:01:00 PM
and some more pictures

the last one showing a snapped bolt for the cam tensioner and the engine bracket and stud I cant remove. Might have to send to an engineering shop to have these removed.

the cam tensioner itself is seized as expected
Title: Re: Engine Strip - I'm nervous
Post by: Trigger on January 04, 2020, 05:10:29 PM
Those crank case shells are good and can be reused again  ;) ;)
Title: Re: Engine Strip - I'm nervous
Post by: waffey on January 04, 2020, 07:00:21 PM
Those crank case shells are good and can be reused again  ;) ;)

Thanks Trigger
Title: Re: Engine Strip - I'm nervous
Post by: waffey on January 04, 2020, 07:01:20 PM
here is the sump pan that's been repaired
Title: Re: Engine Strip - I'm nervous
Post by: Bryanj on January 04, 2020, 07:13:23 PM
Welding looks reasonable when you consider the metal and how oily it was. Try putting the plug in WITH A NEW SOFT WASHER fill the inside with parrafin and see if it leaks, clean it first of course.
Title: Re: Engine Strip - I'm nervous
Post by: Bryanj on January 04, 2020, 07:16:24 PM
I agree with trigger about the shells just make sure you know the exact position they come from as they can not be identified if you dont, as i believe Trigger said earlier
Title: Re: Engine Strip - I'm nervous
Post by: AndyD on January 05, 2020, 08:52:54 AM
Guys,
Bit off-topic but seems that lots of the 400's have broken piston rings (mine included but just on one piston) - is there something 'different' about the engine design that causes this as I haven't come across it on other makes / models?

Cheers,
Andy
Title: Re: Engine Strip - I'm nervous
Post by: Trigger on January 05, 2020, 09:22:55 AM
Guys,
Bit off-topic but seems that lots of the 400's have broken piston rings (mine included but just on one piston) - is there something 'different' about the engine design that causes this as I haven't come across it on other makes / models?

Cheers,
Andy


I find broken rings in a lot of old engines. If the engine has been sitting about for years, the rings will stick and when someone attempts to start it, the stress will break the ring as it starts to free off  ;)
Title: Re: Engine Strip - I'm nervous
Post by: AndyD on January 05, 2020, 10:56:33 AM
Thanks Trigger
Title: Re: Engine Strip - I'm nervous
Post by: Bryanj on January 05, 2020, 11:36:22 PM
I know back in the 70's did a lot of 175 twin and 250K4 with broken rings. Chased most of them down to being thrashed from cold
Title: Re: Engine Strip - I'm nervous
Post by: waffey on January 07, 2020, 07:04:21 PM
Hi

has anyone bought these bearings (not from Mr Honda himself) but from a normal bearing supplier?

If so, can you tell me the size or the bearing number.

Thanks
Title: Re: Engine Strip - I'm nervous
Post by: Bryanj on January 07, 2020, 07:09:47 PM
Dont think you can, if anybody knows for certain Trigger will
Title: Re: Engine Strip - I'm nervous
Post by: Deano400 on January 07, 2020, 10:16:50 PM
There's one on fleebay.
https://www.ebay.co.uk/itm/NOS-Genuine-Honda-CB350-CB360-CB400-CB750-Gear-Box-Needle-Bearing-91022-377-008/303344241789?fits=UKM_Make%3AHonda&epid=649121996&hash=item46a0b9cc7d:g:0qoAAOSwaaJa3baV
Title: Re: Engine Strip - I'm nervous
Post by: Deano400 on January 07, 2020, 10:20:28 PM
Had to get one myself.
Title: Re: Engine Strip - I'm nervous
Post by: Trigger on January 07, 2020, 10:23:24 PM
Hi

has anyone bought these bearings (not from Mr Honda himself) but from a normal bearing supplier?

If so, can you tell me the size or the bearing number.

Thanks

What is wrong with the old bearing  ? If that bearing has gone then, the shaft is damaged  ;) You can get the bearing cage and pins from any bearing supplier but, the housing is Honda only .
Title: Re: Engine Strip - I'm nervous
Post by: Deano400 on January 07, 2020, 10:31:43 PM
Believe it not Graham, even though mine had been installed wrong at the factory and the shell was split, it ran as smooth as it should and the shaft was perfect. It had done over 45,000 miles on that bearing.
Title: Re: Engine Strip - I'm nervous
Post by: Trigger on January 07, 2020, 10:44:30 PM
Believe it not Graham, even though mine had been installed wrong at the factory and the shell was split, it ran as smooth as it should and the shaft was perfect. It had done over 45,000 miles on that bearing.

The housing is only a housing, if the pins are badly worn then, the shaft is damaged  ;)
It is the pins that are in contact with the shaft, not the cage or the housing
Title: Re: Engine Strip - I'm nervous
Post by: waffey on January 08, 2020, 06:37:11 PM
Trigger, it all seems fine. I was going to replace as I had the gearbox apart. I'll re use them. I've ordered two replacement bearings than run in the gearbox though they seemed fine.
Title: Re: Engine Strip - I'm nervous
Post by: Trigger on January 08, 2020, 07:08:53 PM
Trigger, it all seems fine. I was going to replace as I had the gearbox apart. I'll re use them. I've ordered two replacement bearings than run in the gearbox though they seemed fine.

You old boys worry too much.
 If gear box bearings are good then just reuse them. I only change gear box bearings when they have play or have gone rusty from standing   ;)
Title: Re: Engine Strip - I'm nervous
Post by: waffey on January 10, 2020, 05:41:53 PM
hi,

I've had to take the crank case topto an engineering to remove the cam chain adjust bolts. Can some tell the size of the bolt so they can drill out, retap etc

items 177 and 219 I need dimensions for or does anyone have parts I could purchase before I go source new?

they are also removing the bottom e
Title: Re: Engine Strip - I'm nervous
Post by: Bryanj on January 10, 2020, 06:43:13 PM
219 has an m6x1 thread in the crankcase, maybe im blind but cant see a 177
Title: Re: Engine Strip - I'm nervous
Post by: waffey on January 11, 2020, 12:38:23 AM
sorry I cut 177 off
Title: Re: Engine Strip - I'm nervous
Post by: Bryanj on January 11, 2020, 07:02:38 AM
Never checked that one but i suspect m6x1 same as the adjuster bolt
NB remeber the adjuster bolt is a "special" as there is a bit of m8 thread under the head for the lock nut
Title: Re: Engine Strip - I'm nervous
Post by: waffey on January 12, 2020, 05:23:22 PM
does anyone have an adjuster bolt to sell?
Title: Re: Engine Strip - I'm nervous
Post by: Bryanj on January 12, 2020, 05:44:05 PM
Do you want this rocking horse poo ready chromed?

There was somebody making them, not sure if it was ttr 400
Title: Re: Engine Strip - I'm nervous
Post by: Nurse Julie on January 12, 2020, 05:51:10 PM
Do you want this rocking horse poo ready chromed?

There was somebody making them, not sure if it was ttr 400
Yes, Kevin, TTR400 makes them and a thing of beauty they are too ( not that I have one that posh fitted)

http://www.ttr400.com/photo_3.html
Title: Re: Engine Strip - I'm nervous
Post by: Bryanj on January 12, 2020, 05:57:39 PM
If you cant get that try
http://noxandrattles.co.uk/index.htm
Title: Re: Engine Strip - I'm nervous
Post by: waffey on January 12, 2020, 08:16:34 PM
much appreciated, two new websites I didn't know existed  8)
Title: Re: Engine Strip - I'm nervous
Post by: waffey on January 16, 2020, 11:30:07 AM
Hi,

just had one of the pistons measured and looks like a standard 51mm piston. As suggested before, do I got straight in the 0.50 mm over size for a rebore or the 0.25mm?

Thanks
Title: Re: Engine Strip - I'm nervous
Post by: Nurse Julie on January 16, 2020, 11:38:28 AM
Hi,

just had one of the pistons measured and looks like a standard 51mm piston. As suggested before, do I got straight in the 0.50 mm over size for a rebore or the 0.25mm?

Thanks
I would suggest go straight to +.50
Title: Re: Engine Strip - I'm nervous
Post by: waffey on January 16, 2020, 11:52:11 AM
always take the advice of a nurse ;

Thanks Nurse Julie
Title: Re: Engine Strip - I'm nervous
Post by: Nurse Julie on January 16, 2020, 01:30:19 PM
always take the advice of a nurse ;

Thanks Nurse Julie
Do you know what the piston to bore clearance is at present?  It depends on what the clearance is as to what size over you need to go. It's no good going +. 50 if the bores are already worn up to near, or over . 50 already. I'm assuming the clearance is well within spec at present 🤔
Title: Re: Engine Strip - I'm nervous
Post by: waffey on January 16, 2020, 06:45:28 PM
Nurse, nurse...….yes, its an assumption that the bores are ok, I need to somehow beg, borrow or steal a measuring device to check the internals.

next on my slop chit. I still cleaning bits and bobs and have to make a place for the frame which should be due back by the end of the month.

gotta work on the TL soon as well...….
Title: Re: Engine Strip - I'm nervous
Post by: Bryanj on January 16, 2020, 06:50:47 PM
If you come past gloucester i will measure it for you
Title: Re: Engine Strip - I'm nervous
Post by: Nurse Julie on January 16, 2020, 07:18:20 PM
If you come past gloucester i will measure it for you
Ditto.... But I doubt you will be passing Lincolnshire 😁😁😁
Title: Re: Engine Strip - I'm nervous
Post by: waffey on February 15, 2020, 10:46:15 AM
Help, how do I remove the in neutral switch from the casing?
Title: Re: Engine Strip - I'm nervous
Post by: taysidedragon on February 15, 2020, 10:53:55 AM
Help, how do I remove the in neutral switch from the casing?
You are joking... aren't you? 😁

The photo shows the camchain tensioner bolt. 😕
Title: Re: Engine Strip - I'm nervous
Post by: waffey on February 15, 2020, 10:57:17 AM
oooppsssss, just testing, new picture added  :-[
Title: Re: Engine Strip - I'm nervous
Post by: Nurse Julie on February 15, 2020, 11:33:02 AM
Help, how do I remove the in neutral switch from the casing?
It just pulls out.
Title: Re: Engine Strip - I'm nervous
Post by: waffey on February 15, 2020, 06:13:26 PM
Thanks Nurse Julie
Title: Re: Engine Strip - I'm nervous
Post by: mike the bike on February 15, 2020, 09:55:19 PM
It'll be stiff because of the O ring.
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