Thanks limeyrob and thanks all for replying. I also made the same with my guides SRM colsibro oversized adapted to be mounted. Resolved small issues with carburator leaks, once reassembled the engine with new valves, springs and guides it seems to run quite fine, it starts on the first attempt and keep nicely the minimum. When riding for a small round near my homeplace (I still have no insurance) however carburation seems not perfect and I suspect I will not be really able to adjust it. Yet I am learning a lot thanks to you all. We will see... Ciao