My motor has developed a ticking noise in the top. l have looked at bike bandit at the exploded view pictures of the cams and valves, but do not know what usually wears, the tappet or the shim. Any help is appriciated thanks.

sometimes its not wear but things comming out of adjustment. You really should have a service manual to do this adjustment.
once you have the manual you will find its easy to adjust the valves

Here is a service manual for an '03 that You can download.
It is Free

The changes in clearances r a cumulative total.

The shims get very little wear because they get no ''sliding friction.

The Tappet/Bucket is subject to wear from camshaft lobes swiping across the top of them

Wear also occurs on the lobes themselves,
and on the camshaft ball bearings,,
as well as the ''plain bearing'' journal on the shafts And it is bearing surface in the head

Good Luck,
txm42


http://atvonline.co.cc/download-polaris-predator-500-atv-service-manual/#more-28