Yesterday I started cleaning up a set of AA7 cases for a future project.
All of the usual, clean out 30 odd years of grease, dirt and sludge. Run a tap through the threads. Repair the damaged ones. Drill out the broken stud.
Pretty basic stuff.
Then I came to the oil galleries.
They were OK between the tank feed/return ports, just dirty.
The scavenge pick up was blocked.
This will be easy, just wriggle a bit of wire through it!
The 2 right angle bends tended to stop this.
Maybe a bit of 100 psi air?
Might as well use my mouth.
Remove said pick up from the case.
Still no joy.
Wave lit oxy torch at the whole thing until hot.
Flames from the pipe but still blocked.
Next I unsweated the pick up ball housing from the pipe. With a bit of effort i managed to wriggle a piece of wire into the elbow and cleared the blockage.
Just a quick silver solder job to put the pipe together and re-install.
Now for the relief gallery.
As most of you know, this runs from the relief valve to the cam tunnel with a drilling to lubricate the timing gears.
Another total blockage!
So I pushed a wire through the gear drilling while running solvent through the relief.
I managed to clear this bit but there was nothing reaching the cam tunnel.
I managed to wriggle a piece of copper wire from the relief to the bend at the end of the tunnel and again from the tunnel to the bend but even high pressure air wouldn't budge the muck.
I then drilled out the plug in the end of the gallery, not all cases have one.
I still couldn't budge the blockage with a straight run at it, it was probably in the bend and the wire would not go around.
Finally I filled the gallery with solvent and quickly pushed a close fitting rod down it.
Success!
Solvent in my hair but enough pressure to force the obstruction back through the bend and it was then washed out.
And people wonder why it takes so long to restore a bike!
Trev.