I think an oil refresh is recommended every 4 years (but it may be at 2 years along with brake fluid), I can’t recall without looking it up. I wouldn’t change oil seals unless they were leaking or dust seals unless they’d started to go rusty.
Depends on the suspension and the usage really. I remember having my race suspension serviced after three meetings and I honestly could not believe how knackered the oil was. On a road bike I’d probs have it done maybe every 5 years or so perhaps. It’s pretty inexpensive
My 748 had 6000 miles on the clock when I bought it (a good number of years ago), had a full service and suspension set up before I rode it in earnest and the fork oil was masquerading as treacle. Took ages to clean out the gunk. Andy
Apparently, it’s expensive to get Xdiavel forks serviced. I was just quoted almost £400 Considering the expense, I asked if it would cost much more to simply upgrade the fork cartridges. But the price became truly eye watering. Are Xdiavel forks made from unobtainium by Italian elves?
Not sure where you are, but these (https://www.reactivesuspension.com/) fitted Andriani cartridge inserts to my multi in 2014 for around £1000. That was leaving the bike with them a few days. OK, that was 2014…even so, worth a try.
That doesn’t seem unreasonable really, depending what they’re doing. If it’s just to drain the oil, flush and refill on forks you’ve deinstalled and delivered to them then, yes, it’s pricey. However, if it’s to remove and refit the forks, strip them, clean them, fit new oil seals, dust seals, maybe new bushes as well whilst they’re apart, then I’d say it’s reasonable. There’s at least 3 hours work there. The oil & dust seals will be at least £50 for good quality ones, the bushes could be another £30 or so each leg - it soon adds up.
It was basically firmer, with better control on the brakes and better damping. Rear was left stock, down to to finances. It really could have done with a quality shock and a steering damper. High speed weave was not resolved…I suspect down to poor quality rear shocker. He did say that the standard forks had worn bushes…at around 8k !
JWR in Louth did my F4 forks for £300 New seals, dust seals, bushes and oil. He also made a new spacer for the top of the spring on one of the legs. His workshop is in the back of PHR
Last year I had my local workshop rebuild the forks on my NC30 VFR400. I supplied the seals & oil etc. Labour was £50. IIRC to do it myself required a special tool & a possible extra seal in case of error which was about the same cost -except that I went sailing instead of mechanicing
The fork oil change schedule is bike model dependent. For example, both my Multi and Monster 1200 suggest 45,000 kms. (attached) Personally, I would change the fork oil at less than half the scheduled maintenance. Your compression and rebound damping will be less out-of-wack. FYI, The two suspension specialists I know suggests fork service at 20,000 kms but that entails more than just an oil change. Of course, that may be self serving. YMMV.