Maybe those making the rules related to TS and P65 trials dont understand there is a real need to reduce, and not increase build costs? Last pair of modern forks I bought cost £75, and other than seals were in perfect working order, so cost about half what I guess it would be to modify a Bultaco top yoke to get rid of the tiller bar mounts? Without trying modern TS suspension units in direct comparison to the outdated stuff favoured by most riders, its difficult to have that good an idea of how much better the modern units work. But anyone who has been riding for a while will probably remember the dreadful old 4 ply trials tyres? Comparing these to modern radials gives a good idea of the improvement to be expected when you have working rear suspension fitted. Personally I feel that allowing people to ride what to all intents and purposes are modern machines, in events intended for older bikes, is ultimately going to kill the sport, as it will become difficult/impossible to compete unless you have the very latest bike. The modern machine thing is very noticeable in "P65" trials here in the UK, and this trend has been aped by the Spanish in allowing re-manufactured new TS machines to compete in classes intended for authentic bikes (which are far less competitive). Perhaps its time to introduce the idea of a completely new class for TS machines, where the only requirements would be air cooled motor, drum brakes and 2x rear shocks? This would mean greatly reduced costs, and mean something comparable to the very costly modern Spanish TS bikes (£8-10K), could be put together for around a 1/4 of the money.