Rocker Lateral Float

[ibanezlynx]

I need to rebuild my M900 heads. When I stripped them down I lost track of where all of the spacers go. How much lateral movement should I allow in the rockers when I build them up? Should there be any at all? I'm not sure whether to leave a little for thermal expansion....
Thanks.

[slob]

The rockers are steel and the heads aluminium so cold clearance is not an issue (steel expands slower). There should be a shim either side of the spring clip on the shaft.

[pompone]

And a shim where the rocker meets the inner face of the head. Main thing is that both top rocker and bottom (fork) rocker sits comfortably on the cam lobe and the valve is centred too.

[ibanezlynx]

Okay thanks for the advice. I have assembled the lower rocker and have been measuring the gaps with a vernier and feeler gauges. I've arranged it so it is shimmed perfectly within 0.1mm of the centre of the valve. However part of me thinks this is to tight considering the limited sizes of shims that came out of the heads originally. There is a 0.6 mm gap between each side of the fork and the valve so I have a bit of room to increase the movement... Not sure whether to open it up a bit.

[slob]

the gap will grow by ~0.5mm at operating temperature, stop worrying