Z1OwnersClub GB

If i upgrade my cylinder head studs to heavy duty is there any other work required

I was told by a man who knows a lot more about this than me,that it the studs are increased the oil gallery’s that the other studs fit through need to be increased also. It kinda makes sense when you think about it. I’m sure you will get plenty of good advice here shortly. Torque will also increase from what I remember. But don’t ask me the figure.

Yes! The stud holes in some barrel castings taper towards the middle from either end which can cause an oil restriction to the head when using HD studs.
This only affects the two rear outers and the remedy is to drill them to 12mm throughout their length.

So im removing the studs from the crank casing before vapour and painting I will be replacing with HD studs, i was reading some threads and apparently i should measure carefully the length of the studs as they differ in length I’ve noticed that one of middle 4 is a fair bit shorter is this correct?

stusco wrote:So im removing the studs from the crank casing before vapour and painting I will be replacing with HD studs, i was reading some threads and apparently i should measure carefully the length of the studs as they differ in length I’ve noticed that one of middle 4 is a fair bit shorter is this correct?

No! The middle 4 are all the same length.

There are 3 different length studs.

The middle 4 either side of the cam tunnel are the longest .
The outer 4 are shorter .
And the ones in the middle ( between cylinders 1-2 and 3-4 ) are the shortest .

You should measure the installed heights of the stock studs and then fit the APE ones to the same height and mark them level with the crankcase with tape or similar.

This does not mean that the APE ones will be bottomed out in the cases.

After test fitting you should apply permanent red loctite to the stud threads and screw the studs into the case to the correct heights ( indicated by the tape etc ) and then leave the loctite to set.

I’ve measured them now i should wear my glasses one of the middle ones has unscrewed i bit

This may help
Click the pic to zoom



AL