CB400/4 ENGINE STRIP, ASSESSMENT AND REBUILD BY JULIE - NOW COMPLETE

[Nurse Julie]

Ummmm, no, wouldn't call it petty and I did have lots of tools out of the boxes when really I only needed 3 different size spanners and sockets. Anyway, I had a tidy up in the workshop so he's happy again now. It's all ready for me to wreck again tomorrow 

What is tomorrow's plan of action.

Shopping in the morning (food, not bike bits!!) and then I would like to do a leak down test on the head and strip the valves out and clean them up. I may have a go at refacing them if not bent, measure the valve guides and measure the bores and such like. I want to get all the top end cleaned and sorted before I delve into the bottom end.

[Orcade-Ian]

I've just done the engine in the 'other' 400 in completely the reverse direction to those I've done before.  Each part taken off was cleaned, assessed and either painted or plated and then stored.  When the final bit was reached on the strip down - the cases, once they were cleaned and painted everything was ready to build up.  It somehow seemed better than having a whole pile of manky bits and pieces cluttering up the workshop, dripping dirty oil all over.  My enthusiasm seemed to stay the whole course too.  The purists will probably cringe but I painted the bottom casing as well - much easier to keep clean.
Ian

[Nurse Julie]

I'm just doing it the way Trig does with all his engines. He has so many, for example, CB750 engines of customers in at the same time for rebuilds, it's like a military operation. Strip, assess, clean, acid dip cases, welding /machine work, paint cases. Every engine part is then moved to the engine building room and has it's own shelf on the racks. When he's got all the parts needed, which on some of these old engines could mean an awful lot of parts, everything is there, ready for the rebuild. So, if it works for him for all those engines, it should work for my one.

[Nurse Julie]

Well, things never go to plan, I haven’t got half as much done today as I had planned for one reason or another.

The leak down test was fine, no leaks from any valves.

I measured the bores, which are as follows :
        1                      2                    3                     4

   51.097             51.055              51.041           51.064

   51.036             51.084              51.025           51.039   

   51.020             51.072              51.011           51.022
     

The bores have no major vertical scuffs or scratches and look excellent to me but, at the top of 2,3 and 4 there is a little lip that I can feel with my fingers and about 10mm below the lip is a definite score going completely around the barrels that I can easily feel with my nails.
I spoke to Graham about this and asked would honing remove the lip and the score and he said it would remove the lip but if you tried to hone the scores out, you could be very near .25 over and then still no guarantee the score would be gone completely. He then went on to explain that he hones or re bores to the size of a physical piston + the relevant clearance, so was I going to buy a set of +.25 oversized pistons and rings, have a re bore and then find that the score is still there and then have another re bore to +. 50 and buy another set of pistons and rings?. As  have STD pistons fitted, it didn’t take much thinking about on my part as it makes sense to go with the +.50 pistons and rings, so that is what will be done.
The photos hopefully show the scoring. That’s it for a few days as have loads on until after the weekend, when I will strip the head completely.

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[Woodside]

good to see even in  pro engine build workshop....the trusty quality street tin?

[paul G]

As Trigger said Julie do it once. At least you have him to hand for good advice.

[Nurse Julie]

good to see even in  pro engine build workshop....the trusty quality street tin?

Yes Jason, unfortunately no choccies left in the tin. That's in the 'dirty' workshop and is full of a load of rusty non Honda nuts, bolts, Allen screws etc that he finds when stripping engines. He wouldn't have a dirty old tin like that in the engine building room, that is cleaner than an operating theatre !!!

[Nurse Julie]

As Trigger said Julie do it once. At least you have him to hand for good advice.

Yes Paul, it is very handy being able to tap Trig for advice, he has his uses  Joking aside, I don't know how anyone does this sort of engine work just by using a Haynes manual, it is so basic and it doesn't explain 'why' you need to do something a certain way, which is no good for an inquisitive girl like myself.

[paul G]

Carefull you don't get the bug or you will be wanting your own workshop.
How is the 500/550 build going.
Can't remember which it was.

[Nurse Julie]

Carefull you don't get the bug or you will be wanting your own workshop.
How is the 500/550 build going.
Can't remember which it was.

My other bike is almost done now, it's a  CB550 mongrel. The tank and panels should be back from the painters next week. The downpipes are ready to bolt on along with a stubby silencer. Graham has fabricated a new clock bracket because I'm using lots of CB500 parts including CB500 clocks and because of the angle the cables come out of the clocks, they fouled on the headlight bowl. He has also fabricated a side mount number plate bracket. All the wiring is done and she fires. I now need to make the seat. I'm not planning to have it on the road until next spring. In the meantime I have parked her in Grahams office for the winter  [ Guests cannot view attachments ] [ Guests cannot view attachments ] [ Guests cannot view attachments ]

[matthewmosse]

I found a pair of Stilsons / pipe wrench is good for getting studs out of the cases. I bet Trigger has the stud detractors too, they work like the starter clutch with 3 rollers that tighten and grip the stud but I find whilst they are great for putting studs in they are not so good for stubborn extraction and slip and maul threads. Locking 2 nuts together against each other is probably more effective. I've had a few head nuts that have needed a lot of persuasion after buying a few very rough engines. A handy trick is to use a really cheap and nasty socket on the nut, then use a stick welder to stick the socket and nut together, rarely fails, another abusive method using 12 point sockets a bit too small and hammering them onto the rounded nut, Don't use triggers sockets like that, but those horrid cheap sets off the market are fine for that and if lucky they'll withstand a decade of that kind of use saving lots of aggro.

[Nurse Julie]

I was tempted to use Stilsons and the woodwork chisels Matthew to remove that bloody nut !!!

[Bryanj]

Some of those bore marks look like water corrosion, bet the bike was not used for quite a while?

[paul G]

You been using Triggers camera on those pictures of the bores 

[Nurse Julie]

Some of those bore marks look like water corrosion, bet the bike was not used for quite a while?

Your right Bryan, the bike was off the road for at least 8 years according to PO. It may have been off the road at other times in it's life as well, who knows.