Hitchcocks Forum

Hi guys! Got my iron Sixty-5's top end off done valves(larger exhaust),cut seats,reamed guides & have a new low comp Omega piston to replace the OE grenade version, the timing cover is off to block the later breather fitting. My question to the experienced Bulleteer mechanic is the contact area between the discs and timing cover doesn't appear constant so can I test it with engineers blue somehow? What grade of metal polish should be used if I need to lap them with the factory lapping tools?

I should add that the spindle crank for the return has been touching its cover, can I just file a little off or should I double up on the cover gasket?

Unless there’ s some untoward reason for the contact then adding an extra gasket is fine. I used to run double gaskets on inlet and return as well as the lighter springs to reduce load on the spindle teeth. The spindle could easily be rotated with light finger pressure with this setup.

Thanks Ric I will test that out & try to get it as free turning as possible.

I lapped mine with fine grinding paste until I had an even fine matt grey appearance on the alloy, similar to what you aim for when polishing a head or grinding in a valve. I'd avoid autosol, you're not aiming for shiny, shiny doesn't seal well.



Here's mine after lapping in new pumps, the black spots are inclusions/voids in the crappy alloy.

Oh, if you look closely at the picture, you'll see where I've relieved the "points" on the sides of the pump chamber. Just make sure the pump piston isn't fouling these at all. Mine had to be relieved a lot due to using high flow pumps. However, if it was touching slightly, I suppose it could make the pump cockle-over at an odd angle to clear leading to uneven wear and it striking the cover.