I had my front fork oil changed at my 30,000 km service on my Sportster. Now when I sit on the bike the forks sag to about half way. The mechanic has redone it, even changing the springs but it it still the same. . Has anyone else had the problem after a front fork service ? Any solutions ?

I meant saging not saying

stock spring are shit  so are progressive, buy race tech , when bike weight on ground sag should only be 3/4 " 19 m.m. no more than 25 m.m. when you sit on bike same again only 3/4'' more sag  or spring is too soft  or spring preload is wrong , spring preload should be also 20m.m.  cheers,      use a straight rate spring not a dual rate spring only or you will always have this trouble 

AXTELL do a big bore kit for the Sportster 88c.i. 1450 c.c. 115 + hp easy great street bike 

Sorry about your problem.

If bike sags & can't support your weight when you just sit on it, it is the spring's not the oil or amount or weight of oil. the oil just controls the rebound, sounds like they put in progressive springs as cheap easy to get, but like Daddyracer said shit they also come short with a plastic tube to adjust preload. 

i would just take it back to guy who did the job tell him to put more preload on the springs.

Also thought i would point out, if they did the job with load on the fork & fork cap off, then put the spring & oil in then did cap up there would be less air inside each fork. you need weight off the fork so fully extended when you screw the fork cap back in.

stock spring are crap & will sag