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CB400/4 ENGINE STRIP, ASSESSMENT AND REBUILD BY JULIE - NOW COMPLETE
Nurse Julie:
--- Quote from: paul gledhill on October 03, 2017, 10:25:55 PM ---
--- Quote from: Nurse Julie on October 03, 2017, 09:31:49 PM ---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 ::) ::)
--- End quote ---
What is tomorrow's plan of action.
--- End quote ---
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?
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