they started in heavy old hard to work with Duralminium but turned into engineering plastics on a a KTM300 back in 2000 and have worked brilliantly ever since
when i first bought my CCM404 in 2009 i cracked a flywheel cover racing as the bike had no sumpguard
so i rumaged around in the shed again and found a piece of 12mm Acetal (tough plastic) and some 3mm ali
the plastic wasn't big enough, so it was a combo
well its done well for 3yrs and had some big hits, inc 5th gear grounding offroad
i had an offcut of black 10mm HDPE left over from the Rally-Alp project
its very tough and lighter than ali
http://www.directplastics.co.uk/hdpe-sheet
cheap at £20 and easy to work with jigsaw and heatgun, plus 2 hours and some patience
great for budget tight arses like me, or if you have a bike you can't find a heavy ali £90 plate for
