My New Project arrives after a 44 year wait!

[Laverda Dave]

Whilst the Triton is undergoing additional work due to a porous cylinder head I thought I’d crack on with the strip down of the ‘Rat’ CB400-4 mainly to determine if it is worth restoring considering its history (the engine being sand blasted in one piece and being painted black by the PO about 35 years ago being one concern).

So far it’s been a tale of woe and it’s not looking good. The PO had been riding the bike until it was pushed into the shed 20 years ago. I don’t know how he rode it, it was a death trap! Four engine mounting bolts were missing (front upper and front lower, both sides). The rear engine mounting bolt is a piece of studding! The ape hanger bars move backwards and forwards with just a slight push. When I drained the oil it was like thick black treacle with thick sludge in the bottom of the sump pan (that also has a stripped oil drain bolt thread with an oversized bolt fitted).

Stripping the engine has been a challenge; I thought I was going to break the fins trying to separate the head from the cylinder block as the black paint was so thick! I managed to split the cases today to check the crank and shells as this will determine if the rebuild is going to be worthwhile. The cam chain tensioner horseshoe spring and plunger was still in its fully compressed position, the horseshoe being completely seized due to the cam chain wearing a grove into it.  Strangely the PO told me the engine has never been taken apart although the blue hylomer everywhere would suggest otherwise!

When I checked the crank journals four of them looked to be in good condition but when I inspected the centre journal I noticed a score mark deep enough to feel with a finger nail. The score mark does not go all the way around the journal and is about 4mm long at its deepest point. The corresponding shell bearing is equally scored in the same place indicating the bearing has picked up some grit and possibly sand from the sand blasting years ago.  I’ve yet to measure the remaining journals with green plastigauge but I would value some expert opinion on the condition of the centre main journal before I start wasting my time (see photos).

I also noticed what appear to be several cracks on the lower main oil gallery with evidence of an overlong lower engine mounting bolt being fitted (and obviously removed as these were not fitted to the engine when I bought the bike). I only noticed the potential cracks when I scrapped the thick black paint from the area (see photo). When I say ‘cracks’ could these be casing marks as they appear to be proud of the surrounding metal. If they are cracks they will no doubt open up when the engine gets warm and leak oil. Has anybody had any experience of repairing these cracks if that is what they are?

In view of the above I could be looking at a scrap crankshaft and potentially scrap cases as well! If this is the case I will probably break the bike for spares otherwise it will become a money pit. Any thoughts welcome please!

[McCabe-Thiele (Ted)]

Ive sent you a PM about some parts I have.

[Trigger]

The 400 has lot of casing marks on the engine and you will not know if they are marks or cracks until the engine is totally cleaned up and assessed. If they are cracks they are easy to alloy weld repair. I can't remember the members name but he lived in Peterborough who was in a panic with his 400 engine and thought it was cracked. After i had a good look at his cases, it was just casting marks.

Looks like something has got into that centre crank pin to make that deep score 

[Bryanj]

I agree, with a light polish and new shells that would probably run ok fora bike not used flat out or daily driver.
Cases need good cleaning to asses and that has def been apart before.
There will be parts out there to rebuild it but as you say cost may make it unviable

[AndyD]

Hi Dave
I feel your pain - guess it's the 'fun' of taking on a new project, hoping all will be well when you start looking closely while always knowing it's unlikely!

Deciding what is worthwhile is something I wouldn't dream of commenting on as my track record is awful - the 400/4 you kindly had a look at with the sidestand issue a while ago is the perfect example. A basket case with evident bodgery in all areas even before digging deep, but still thought I'd give her a go and have sunk far too much money and time into a bike I'm not even sure I really like!
Still haven't gone back to sorting what to do with it so just sits in the garage staring back at me!

I've got quite a lot of spare bits and bobs for the 400 including engine parts and lots of tools (and now time as well) so happy to help if I can if you decide to go ahead and try to save the bike.

Cheers,
Andy

[smoothoperator]

Those marks on the case near the engine mount look almost identical to mine, which as Trigger points out he quite correctly assessed them as casting marks, the engine was fine once rebuilt. I bought a spare crank and cases at the time which I didn't need, I still have them if they are of any use to you. Panicked of Peterborough!

[McCabe-Thiele (Ted)]

Ditto to that.

[Laverdaroo]

Yup give it a clean and you’ll see their casting marks Dave, mine was the same and I was fretting a bit until an old boy I know bobbed by for a brew and after taking one of these all round Europe in his 20’s, said exactly that. Casting marks all day but without a clean you won’t know. Get it vapour blasted and at least it’ll be spotless and you’ll be able to work out what’s what.


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[Laverda Dave]

Thank you everyone for the advice and the PM's.
I'm going out into the garage today to give everything it's first clean just to get the treacle like oil off the casings and shafts etc along with the smell of the rats pee!
I think I will have to fit another crank as I don't like the thought of spending a shed load of cash on parts knowing one journal on the crank is marked. I would like to keep the cases as this was original engine of the bike (or I hope it is, I'm still waiting for the V5 from the P/I). I'll take some more horrific photos of the carnage as I go along, parental advisory may be required to view them😳.
It is a shame the bike hasn't been looked after during the past 44 years from when I first saw it but hopefully I can restore it back to it's former glory👍

[Johnny4428]

Good luck with it Dave, will be interested to hear on progress and hopefully not too many horror stories. 😜

[McCabe-Thiele (Ted)]

Hopefully your engine cases do not have too many C codes -  a nice combination  of A's & B's is easier to find mains for.

[Laverda Dave]

Hopefully your engine cases do not have too many C codes -  a nice combination  of A's & B's is easier to find mains for.

That could be my first bit of luck Ted, they are marked AABBB

[McCabe-Thiele (Ted)]

Hopefully your engine cases do not have too many C codes -  a nice combination  of A's & B's is easier to find mains for.

That could be my first bit of luck Ted, they are marked AABBB

They will be easy enough to find shells for I think DS stocks pretty much all aside from black mains & there are other suppliers iirc in the Far East.

[Laverda Dave]

A quick update before I head off back into the garage to go elbow deep once more into a parts washer (note to Santa, can I have an industrial parts washer for Christmas please .
So, the engine is now fully apart and everything has had its first clean to remove the treacle that was once oil. I'll give everything a second clean before I begin the close examination and measuring up. Some things have become obvious though as the parts have been removed. From the state of everything and the presence of various colours of instant gasket including red, orange, blue and clear the engine has been apart before. The cam chain was not tensioned following the initial rebuild as the spring is still full compressed on the push rod resulting in the pivot pin of the horseshoe being eaten into by the flailing chain and seizing solid. On removing the valves I found one thrust washer (if that is what it is called) missing between the inner valve spring and the head on No.4 inlet (another addition to the much needed parts list!).

The oil pump has also been apart before as the two dots on the rotors are not on the same side and facing up as they should be. Strangely enough there is not a single scuff or any other mark on the rotor tip or scoring in the body, I suspect a new oil pump was fitted at some stage; probably it picked up sand from the previous ham fisted blast treatment the engine was subjected to?
I found the bike has been fitted with Pirana Ignition, that's a blast from the past for sure although I'm not sure if it works, I will have to test it.

The real downer proved to be the front and rear mudguards. Both these items are genuine Honda and the chrome is in really good condition on both, I thought I had a result here but alas, NO:-[. When I removed the tombstone rear light fitted by the PO it revealed two badly drilled big mounting holes drilled into the mudguard. A similar story occurred on the front mudguard, when I removed the 'shopping trolley' Harley type front fender guard it revealed four 8mm holes drilled into the mudguard mounting/brace piece, sod it :'(. The easy way out would be to fit blind grommets in the holes but that would look really tacky and is a bodge too far for me. I am going to investigate having a very small plate welded at the back of the holes and maybe filing the holes with brass or copper and smoothing it off level with the surrounding profile. Hopefully any welding will not distort the surrounding metalwork and a re-chrome will take. Any thoughts, has anyone tried this method before and does it work?

Back to the shed now, more news as it happens

[Mikep328]

Re the oil pump rotor marks - mine was the same, marks on opposite sides, but there was no evidence the pump had ever been removed.  Others have said the same re the marks 'mismatched' so I think it wasn't a big deal upon assembly at the factory.