Thanks Fred, I scrape what i can off first without damaging the piston, then scrub with a nylon brush and brake cleaner. Then if it still needs a bit more, I use carb/throttle body cleaner with a brush. I try to get the the carb cleaner on and off quick and rinse with brake cleaner or equiv. as it eats nitrile gloves very fast, and I don't like the idea of using it on aluminium unless i need to (even though it is for throttle bodies and carbs?). Once i'm happy enough I put them in an ultrasonic cleaner to shake any stubborn crud from oil holes etc.
Same process with carbs (without the initial scraping), and other engine and general parts, but with carbs and some parts I also soda blast them (each individual part) before going into the ultra sonic cleaner.
Its quite time consuming but it is always worth the extra effort.
Looking excellent. Funny thing is that is exactly the jobs I have been doing too. Headlights, cockpit, starter... Except, you did it better, taking before and after pictures. Looking really first class! Keep up the great work mate.
New main, and gearbox bearings being installed. I heated the cases up in the oven (tight fit) to around 100 deg C, and had the bearings in the freezer.
The gearbox main and counter shaft bearings dropped straight in, but the main crank bearings had to be pressed in. Take care when aligning the bearing tabs.
I needed new exhaust valves, but the intakes are fine. A good hand grind will be all that's needed.
Grind with paste, starting with coarse grit, then fine, until a clear sealing ring is seen all around the valve and seat. Repeat for all, including the new valve/s to ensure proper sealing to the worn seat.
If the valve seats are in really bad shape, they may need to be re-machined/cut, luckily mine were in decent shape.
When I'm happy with how they look I clean the valve and seat, install all valves, seals, springs, retainers, spark plugs, then use white spirits to test that all valves are sealing properly. If not, grind again until the fluid doesn't leak.
New collets/retainers were used with the new exhaust valves to match, installed with new stem seals for all.
When installing the valves, I apply a light 50/50 mix of moly grease and oil to the stem/guide so it is lubricated on first start up.
Clean both surfaces with brake clean or acetone (not the gaskets!), install new head gaskets, don't forget to install the locating dowels, and on they go.
I also needed new valve tappets/adjusters for the exhaust valves, as the old ones were quite worn. I would replace them anyway as the exhaust valves are new, and they are inexpensive. Intakes are fine.
Rocker assemblies, cams, and new timing chains installed.
Valve clearances and cam timing set to spec.
I installed the flywheel/starter drive and magneto first, then made up a crude tool to lock the counter shaft (in gear) against the the magneto, with the old front sprocket and some steel bar stock.
This is needed to tighten the clutch center lock nut to 127Nm, as there is no way to hold the rotating assembly without using a special tool. It worked a treat, I have since cut the tool down and cleaned it up for future use.
Oil pump drive, clutch assembly installed.
A few gaskets and O-rings, and the engine is ready for paint.
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