My 2007 66 RC2X 180mm is bottoming out at 175mm of travel (OK, nothing is perfect - even zocchi!), but when I unscrewed the top cups and then bottom it letting springs witch cartridges come out it is bottoming 5 mm deeper and then reach the full 180mm of travel. It seems that the fork is not bottoming when uppers slide to the max to the lowers but it is blocked 5mm earlier maybe by cartridges? Is it normal? I don't want to break anything when doing bottoming tests...and where the fu**k are my 5mm of travel!?
If somebody has that fork try to check that and let me know
it also may be the bottom out bumpers... bottoming out softly will not compress the hard rubber bumpers much, but a hard bottom out will squish the bumpers, and theres maybe another 2-3mm of travel.
honestly, its just 5mm, it wont make a difference either way
It's either too much oil, or the 5mm's is just taken up by the internals... when everything compacts, it can't just disappear. Between your bottom out bumpers, the dampers, the spring, preload spacers, all the stuff thats in it, you're probably losing some travel somewhere in the process. If it doesn't sound gross, don't worry about it.