SOHC.co.uk Forums > Project Board
CB750 Barn find project - First Timer
Underdog1:
--- Quote from: K2-K6 on January 07, 2017, 08:44:14 PM ---They often used paint of various types inside castings to avoid any porosity in the metal allowing the oil to pass through to the outside. Not quite sure of the reasons it's used in these engines but someone else may be able to add more to it.
They were at the time trying to make them as leak free as possible in comparison particularly to British made engines. I guess you'd get too much drop out from production runs to even test them all, so easier to use an oil resilient paint in coating the inside to reach the consistent standard they were aiming for.
--- End quote ---
Makes sense I suppose.
My concern is how likely that bubbled paint is to lift off eventually and block oil ways.. maybe I should just strip it all off (well all the stuff that's bubbled anyway)
hairygit:
Personally I would remove the loose/bubbled paint, any solid debris breaking loose inside the motor can cause havoc. Even if it doesn't block the pick up gauze on the pump, do you really want it gunging up the gear clusters and gearbox bearings?
Underdog1:
--- Quote from: hairygit on January 08, 2017, 10:27:55 AM ---Personally I would remove the loose/bubbled paint, any solid debris breaking loose inside the motor can cause havoc. Even if it doesn't block the pick up gauze on the pump, do you really want it gunging up the gear clusters and gearbox bearings?
--- End quote ---
Yeah I don't want to stick it all back together only to shart itself within 5 minutes. I'm going to try and get some sandpaper into the gaps at the front of the upper crankcase and see how easily it comes loose
Underdog1:
Following on from the above I've given it a good hard scraping with a sharp screw driver and the bubbled paint is absolutely rock hard and definitely doesn't want to come away. It's like the gasket remover has just wrinkled the paint up. If the paint is looking like it wants to stay on could the wrinkled/bubbles paint cause any problems with oil flow where it is (in the recess in front of each cylinder in upper case)?
Underdog1:
Right I'm back home again, got a week off too so I can work on this heap ;D
Got the crankshaft, gears, countershaft, gear selector bits, kick start and final drive in today. Just need to source an o ring for that dowel thing for the oil gallery at the front of the crank cases and I'll be ready to close the bottom end.
The gear selector gubbins took ages, seem to have them in right now though.
I've used graphogen on the crank and bearing shells, I applied it relatively thick and from just placing the crankshaft into place its oozed out onto the case mating surfaces.. do I only need a thin layer of this stuff? Anything else I need to think about pre lubing?
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version