No doubt about that Thunder... first time they were rebuilt at Harris Performance, the main importers, and the second time at Kais Performance, Manchester (authorised dealer) and they were never as good as they were when they were new. Sherpa had his rebuilt elsewhere and was happy with them when he got them back.
One of those things I s'pose... All I know is I've ridden high mileages on the Öhlins and the Wilbers, summer and winter, through rivers and deserts, and when the Wilbers were rebuilt they were as good as new inside and out, but we couldn't say that of the Öhlins!
Ten to fifteen thousand miles and the Öhlins were either leaking or bottom ball joint seized and grotty, or both... and the paint on the springs peeling off. Not so with the Wilbers, they only went back at 20,000 miles as a matter of routine, cos Wilbers wanted to have a look at them... as good as new. They put a new main seal in as a matter of course because the units were stripped down, (the girlfriends and mine) but they didn't want one.
No doubt about it MikeP... good suspenders are worth 10bhp over stock units
That's my sixpenneth