Doms CB550F1 project

[Nurse Julie]

Lots of pitting on the shells and a gouge out of the left side.

[DomP]

OK, so I need to be determining what colour shells I have fixed and replace all marked shells? The crank appears OK to me

[Trigger]

Gear box dogs look fine. I would plasti up the shells as long as you run your finger nail across the crank journals and don't feel any grooves 

[DomP]

Gear box dogs look fine. I would plasti up the shells as long as you run your finger nail across the crank journals and don't feel any grooves 

Can't feel a thing Trigger, I'm not sure what step to take next to be honest...strip it all out and clean it up and check bearings?  From what I can see the primary chain hasn't either the casing at all.

[Oddjob]

Far better than I expected Dom.

You need to rotate the gearbox and take another pic, although it looks fine in the pic posted there could be damage underneath we can't see.

Shells don't look that bad TBH, some minor pitting, most likely from contaminants in the oil sitting against the shell when it's been stood. Crank journal we can see looks ok.

Primary chain looks toast TBH, but check with the tank track test and see what it looks like then. Strip the engine completely, if nothing else it needs a really good clean.

Gear selectors look fine.

Anything sitting in the sump? little bits etc.

Looks like the dreaded red hermetite or instant gasket, really plastered it on either way.

Can you see the crank markings? the printed letters and numbers? What are the letters on the back of the lower crankcase as that will show what colours you should have fitted, well within 2 colours anyway.

Need more pics but looks good up to now.

[Bryanj]

Again looks ok apart from dreaded rtv jointing which has killed many honda engined after blocking restrictor jets.
Take everything out, remove ALL the orange krap an thourouly clean everything.
I would plastigauge the crank and check clearance.
REMEMBER to keep all shells in the place they came from

[DomP]

Far better than I expected Dom.

You need to rotate the gearbox and take another pic, although it looks fine in the pic posted there could be damage underneath we can't see.

Shells don't look that bad TBH, some minor pitting, most likely from contaminants in the oil sitting against the shell when it's been stood. Crank journal we can see looks ok.

Primary chain looks toast TBH, but check with the tank track test and see what it looks like then. Strip the engine completely, if nothing else it needs a really good clean.

Gear selectors look fine.

Anything sitting in the sump? little bits etc.

Looks like the dreaded red hermetite or instant gasket, really plastered it on either way.

Can you see the crank markings? the printed letters and numbers? What are the letters on the back of the lower crankcase as that will show what colours you should have fitted, well within 2 colours anyway.

Need more pics but looks good up to now.

All conrods are marked E and 2, the lower crankcase is AABBB, all of the gears are clean when rotated, no chips or marks.  The sump had some fragments of hardened rubber that I assume must be from the camchain tensioner although there is a tiny bit missing from the nylon oil deflector (?) 

While I'm in here I think for the sake of £48 I might as well do the primary chain, clocks show 32k if I trust they are original, or the engine for that matter as I've not checked.  Replace al oil seals and bearings too?

[DomP]

Again looks ok apart from dreaded rtv jointing which has killed many honda engined after blocking restrictor jets.
Take everything out, remove ALL the orange krap an thourouly clean everything.
I would plastigauge the crank and check clearance.
REMEMBER to keep all shells in the place they came from

Yes I'm moderately pleased with what I've found, glad I cracked it on too!  Looks like I'll be needing your cylinder reboring services Bryan, would it be jumping the gun to go ahead and get it to you?  IMD or David Silvers piston kits?  Obviously I'll hold off on them until you know how much oversize you have to go.

I'm still tempted by a cam reprofiling while it's all apart if it will be a worthwhile improvement, if my pocket allows!

[Bryanj]

You can bring me or send the block, i dont do any blasting, cleaning or painting  thats down to you.
Put up a pic of the inside of the lower case and lets see how much the chain has et away, 550 usualy less than 500.
Mileage dont mean much on an old bike, it could have babied or totaly hammered, i know the primary dampers are as expensive as the chain but they will be rock hard now so need changing.
There will be markings on the crank for pin sizes but if you cant find them bring up the crank and i will mic it for you

[DomP]

You can bring me or send the block, i dont do any blasting, cleaning or painting  thats down to you.
Put up a pic of the inside of the lower case and lets see how much the chain has et away, 550 usualy less than 500.
Mileage dont mean much on an old bike, it could have babied or totaly hammered, i know the primary dampers are as expensive as the chain but they will be rock hard now so need changing.
There will be markings on the crank for pin sizes but if you cant find them bring up the crank and i will mic it for you

Ah don't worry I'm quite happy doing the clean and paint side of things😉  I'll definitely be doing the primary dampers, I'm a bit unsure what you mean by pin numbers?

Lower case has survived quite well I think.  Maybe I'll call you this week at the times you said now that i know better the state of things.

[K2-K6]

Agree that the bottom end assessment shows a pretty good condition overall.

Something weird about it as barrels upward are generally well worn, in big contrast to the bottom end. Looks almost like two different engines have been combined that have very different service history.

[DomP]

Agree that the bottom end assessment shows a pretty good condition overall.

Something weird about it as barrels upward are generally well worn, in big contrast to the bottom end. Looks almost like two different engines have been combined that have very different service history.

I suppose that's always a possibility, the barrels are quite scored and from everyone's views on here I feared I'd find a right mess.  I feel a lot more positive and about it now.

[Oddjob]

I'm not so sure Nigel, the damage to the liners could be because of water damage etc rather than wear.

You can see where the primary chain has worn partly through the main oil gallery but you can also see it's rubbed on where the camchain tensioner goes as well, which makes sense of why I'm finding so many damaged at the very bottom. It's even worn a slight groove higher up, clearly it's been lashing around.

If you look closely at the crankshaft Dom you'll find some printed numbers and letters, exactly like the ones you can see on the rods. They can be very hard to see, washing the crank in petrol can help. They are all in a line, so if you find one you should be able to see the others without turning the crank.

Yours crankcase letters are good, the A's can only be yellow or green and the B's can only be green or brown. So no blacks, which is good news.

IF you were going to replace them I'd go with 4 greens in the A journals and 6 Browns in the B journals.

You need to split the rods now and check how those shells have lasted.

[DomP]

Thanks Ken, that's good news then re the shell colours.  Are we thinking I need to plastigauge all shells on the crank and conrod then?  excuse my ignorance but what colour or range should I get?

[Oddjob]

Well I’m not thinking that. If I could see appreciable wear then maybe I’d recommend that. But I don’t see wear, some slight damage but that’s from contamination.

Now you can either reuse your existing ones or change them for new ones, that’s your choice, remember though that there are 18 shells and most are around £15-20 each, so the best part of £300-400, Then a pair of chains and damper rubbers, another £150. Then gaskets, seals, orings, roller bearings etc.

Not cheap eh