The first few I did were due to the air bags getting tiny holes in their base, where the air bag sits on the swing arm. Get any dirt, grit, or even gravel in there (and chances are that if you actually ride your Spyder anything like 'often', you WILL eventually get something in there!) and the air bag then sits on that, grinding away at it as the swing arm moves while you ride, and eventually, you'll end up with at least one if not a bunch of tiny holes in the bottom of the air bag, worse if you're unlucky enough to get some chip seal sized rock chips in here!! Once I realised that was happening and that the 'cup type' guards you can get
DO NOT stop that sorta grit getting picked up and wearing holes in the air bag, they just change
WHERE the holes get worn, and make it harder to fix them using slime, then I started doing the slime thing as a preventative, and it works!
I've never had to do one twice, altho there have been a couple of Spyder ACS's I slimed that eventually needed something else replaced in the ACS, so the owner purchased the whole kit & I replaced everything for them, meaning that the air bag was also replaced at the same time; but most got the treatment just the once and are still going strong. Both of the treated air bags that were removed when the new kits went in have since ended up in other Spyders, when
their original air bags failed for some reason or another beyond
just a repairable air bag leak, and the treated replacements are still going strong in their second Spyder host.
The only Spyders I know of that have
NEVER had an ACS problem, be it with the air bag, the compressor, the height sensor, air lines, or the compressor itself, either
NEVER HAD the air bag style ACS to start with, or it was removed when the owner fitted shocks and coils early on, which meant the suspension no longer needed/used the air bag to help carry the load/make it all work properly!! If you've got the ACS, by-passing the compressor & height sensor etc, and making your ACS a purely manually operated system can mean that it's likely to work a lot longer than otherwise, but while ever it's got the air bag, that
WILL ALWAYS remain a 'wear item'; and while the slime treatment can make the air bag last even longer, there will come a time when even that slime doesn't work anymore, so unless you've upgraded the shocks and coils already, you'll be left with a Spyder that no longer really has a suspension set up that's capable of working properly/carrying the load of rider, pillion, ect in normal riding, not without spending a rather painful amount of money on it anyway - which means that you either get to choose to replace all the crappy, no longer working OEM bits with expensive OEM replacements, and by doing so, end up with an ACS that you should by now
KNOW is going to fail again at some stage; or you can replace the whole kit and caboodle with an after market suspension system that
IS capable of carrying the load without the air bag/ACS assistance at all, and in doing so, arguably get a much better ride and handling, etc to boot!
So really, I reckon that you should consider the OEM BRP air bag type ACS as nothing much more than a mediocre attempt to do something that
might have been a good idea if only BRP had bothered to use better quality components and provided sufficient customer service to get it working properly in the first place; but since they
did cheap out on it and used crappy bits that only just manage to do the job
IF everything works properly (which for many, is not all that often) then that means the OEM Air bag ACS is simply another cost cutting/transfer the expense of making it work properly attempt by BRP, since they've fitted 'less than capable' shocks and coils, supplementing them to give the short term appearance of proper functionality by fitting the 'soon to be dodgy' ACS and in doing so, they've once again foisted off all of the 'let's make this Spyder work properly' task and the associated costs of doing that onto whichever
sucke... owners aren't switched on enough &/or don't ask enough of their Spyders to realise they've been had... just like with the Kenda/XPS/crapenda tires!!
I would tell you what I
really thought about this sort of practice, but I'm sure that if I did, the Mod/Admin Team here would come down on me...
HARD! 