Cracked Cyl Head

[Kevin MacBride]

Just a query. A friend was on to me today, he has an Aprilia with what he suspects is a cracked head. Would anyone know of someone familiar with this type of problem. Is it something that would be an issue with Aprilias.

[simonandjuliet]

I am not aware of it being a particular problem - the usual problem is the central bolt which rots at the base and leaves little or no surface to clamp down on. If it really is a cracked head , there are spares available

[ben]

   As Simon say's Aprilia cyl. heads are not  normally prone to cracking.
   If Symptoms like water contamination in the oil or water leakage from the head-gasket area occur it is almost certainly due to internal corrosion of the alloy block.
   If the land around the centre stud has been eaten away due to such corrosion Ken Couzens has a special annular milling cutter that can be used to create a flat land below the original head surface so that an alloy spacer can be fitted to enable the centre stud to be tightened in the normal way without straining the head. Using this cutter means that the  head studs do not need to be disturbed. They are very difficult if not impossible to remove without shearing off as they go very deeply into the alloy block.

[Kevin MacBride]

Thanks for the replies, I'll pass on the information.