CB400F Ressurection - Cam Chain Adjuster Housing Damaged

[SeanFD]

I acquired this 1978 400 Four two years ago – it had been sitting on a shelf for 16, now 18 years – and now that I’ve finished riding for a while, I’ve started working on getting it back on the road.
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I’ve posted this on the US site also, but putting it here too in the hope that someone Not active there might have some thoughts. Hope that’s allowed.

It’s rougher than I at first thought and I now pondering whether to just get it going and ride or to spend more time and money on a more thorough job. I’m inclined, at present towards the riding option.

One thing I discovered today is damage to the cam chain adjuster housing on the crankcase. The adjuster bolt is missing and the hole has been plugged with something. What are my options here?
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Is there a way to repair it properly? Would this involve a complete engine dismantle? Can I leave it as is? Or do I need new cases?
Thanks for your thoughts.

[Nurse Julie]

You maybe able to have the area alloy welded but you don't know to what extent the damage is and you would still need to strip the engine to assertain the damage and have the repair done. In the long run it would probably be cheaper to source a spare engine from somewhere and use the bottom cases from that. Its a bodge that needs rectifying though, it won't stop you using the bike as is, unless the cam chain is knackered, the pivot seized and there is no tension.
Also saw your forks on the USA site, they can be ground down an re hard chromed by Philpots in Luton.

[Bryanj]

Try looking at
http://noxandrattles.co.uk/CAMCHAINADJUSTERREPAIRKIT.htm.

Julie might be worth bookmarking?

Steve is it worth tricks and tips

[Nurse Julie]

Try looking at
http://noxandrattles.co.uk/CAMCHAINADJUSTERREPAIRKIT.htm.

Julie might be worth bookmarking?

Steve is it worth tricks and tips

I sort of remember someone else on the forum recently using it with good results. I think it depends on how much metal is missing around the area as to whether this kit would be an option in this case.

[Bryanj]

True, and i suspect the engine will need to come out anyway but worth looking at i think

[SteveD CB500K0]

Try looking at
http://noxandrattles.co.uk/CAMCHAINADJUSTERREPAIRKIT.htm.

Julie might be worth bookmarking?

Steve is it worth tricks and tips

Done

[Bryanj]

Thanks Steve, for the ammount of machining and in stainless i think that is a cheap price

[Nurse Julie]

Thanks Steve, for the ammount of machining and in stainless i think that is a cheap price

I agree Bryan and a relatively simple fix for some problems.

[Laverda Dave]

I've used it and it works 👍

[SeanFD]

Thanks for the responses.

The repair kit requires engine removal, cleaning, then drilling and tapping a hole to accept the M10 insert? Whether it works will depend on the degree of damage to the case, which is not clear yet. However it is more than just a stripped thread, so some repair may be required first.

I have sourced some cases from Steve Cooper - https://www.400fourbits.co.uk/. There are two sets: one set can come with crank, bearings and rods for £175, or £120 for cases only; the other is cases only, requires the same repair that has been mentioned and goes for £85.

I think this might be the best route for me as I would have to get someone to do the welding and drilling for me and I’m sure that wouldn’t be cheap, if I can find someone.

I know on the CB750, the cases are matched but I can’t remember if they are paired with the crank; is it the same story with the 400? Can I just get the cases and then fit my own bearings and crank, assuming they are OK.
The engine number on this set is 1015*** while mine is 1084***; no problems here?

I’ve looked at Philpotts and the cost is £195 to rechrome the pair. DSS sell repro legs for £95. Anyone have any experience with these?

[Bryanj]

You can transfer the crank and rods but will almost certainly need new main shells as both crank and cases are coded, if you need all 10 thats about £100 so having the complete one makes more sense.

You may not need all 10 it depends on case codes found stamped at the rear and normaly A or B

[taysidedragon]

Sean, my fork legs are from DSS and they've been fine so far, but the hard chroming from Philpotts will be far superior.  If you have the time get your legs done by Philpotts (and your forks too!) 😁

[Spitfire]

Got a replacement leg for my 750F1 from DSS in 2007, still fine but not as shiny as the original.

Cheers

Dennis

[SeanFD]

So I was doing a bit on the bike yesterday and some parts are not as bad as they looked - that’s not to say they’re good, but ...

Anyway, I decided that since funds are limited, were possible I will make do with existing parts, cleaned as best I can, and repaired where necessary and possible. New parts are expensive and there’s little point in buying used ones that may or may not be any better than the ones I have. Only safety or legal reasons and good maintenance practice will “permit” new - so I will be using new oil 

The fork legs are not as bad as they looked. The rust and pitting is mostly above the area of travel; I will try to smooth the lower area and see how it goes, worst that can happen is that the seals leak and I have to replace legs and seals later. Both legs have an area of wear just above the dust cover
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I think this is due to an abrasive paste of dirt and oil collecting under the cover and Grinding away at the chrome?

The rear mudguard is a bit more problematic.
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The bits that remain are solid  -ish, so I’m going to apply my limited body-work skills and try to patch the holes; most of them are under the seat and out of sight anyway.

I’ve bought the replacement cases, but for now I’m going to go with things as they are. If cam chain is a problem then, I’ll use them sooner rather than later.

So, hopefully, by the end of the month I will have a running, if somewhat tatty, little bike to enjoy while I sort out her big brother. 

[Laverda Dave]

I think your new seals will not last long in those legs. I have heard of people rubbing down the worst of the rust and repairing with araldite and then filing it smooth but it doesn't last long.  By the time you've taken the legs apart a few times to fit new seals it may have been cheaper to get the them reground by Philpotts in Luton or Dynasurf?