BOS Deville oil change??
Rightio. Ill try remember.Posted 5 years ago
Let all air out of fork
Undo silver adjuster (3mm Allen head)
Undo grub screw on red adjuster
Put bucket under forks
Undu footnut (17 mm ish)
Undo other footnut (5mm Allen)
Before you totally undo them, tap with mallet to break the seal (with the 17mm ish socket on to prevent damage)
Pull the lowers down a few inch and leave to drain
Pull lowers off
Cycle rebound rod to push the rest of the oil out
Clean lowers and replace seals if needed
(You can’t get bos ones without a service)
To ref-fitPosted 5 years ago
Slide lowers back on
Put footnuts back on and adjusters
Undo rebound cap (red bit on top of right leg)
Push forks fully down and lift out the rebound rod as far as it’ll go
Get your syringe and oil
Squirt oil into the rebound stanchion the push and pull rebound rod a few times to bleed the oil
Keep repeating till its at the correct level
140 = 60mm from bottom of threads
160 = 50mm
170 = 58mm
All above are with the fork fully compressed
Screw rebound cap back on
Pump up and robs your mothers brother
Update for anybody else who’s going to do this.
I’ve been informed by the person who did this about the best oil to use:
Apparently the oil BOS use has a 15.60 cSt@40C viscosity, and the closest thing to it is actually the 2.5wt form of Motul Factory Line (15 cSt@40A viscosity), not the 7.5wt, like most people use.
Hope that helps somebody. I’m just passing on what I’ve told.Posted 4 years ago
For anybody that cares, the service is done and the fork’s back on the bike and plusher than it’s ever been. I think 5wt oil might be the way to go next time, though, because it feels like there’s less damping than there was before with the same compression/rebound settings. Or I might get a bottle of 7.5wt and experiment with mixing with the 2.5wt. Hope this helps somebody in the future.Posted 4 years agofbkMember
Great info on this thread – much appreciated.
Just to add a word of WARNING to any Deville owners out there, DON’T believe the manual when it says only service the forks every 6-12 months. I’ve had mine for just over 6 months of not particularly hard use (I tend to use my winter HT in the real mud/slop etc) and thought I’d play it safe. Dropped the lowers and found a nice score mark along the length of the stanchion. From a brief telephone conversation, the chances of BOS warrantying this is next to zero so prevention is much better than cure!Posted 4 years ago
Oh, one more thing to add. The oil fill levels should be measured from the top of the stanchion/where the top cap meets the stanchion/crown, not the bottom of the threads.
I’ve had a ride of my fork and it feels ridiculously plush and with the extra oil in the air spring lower leg, it should feel like this for longer now. I used some Fox 10wt Green because it’s one of the best out there for lubrication but any 10wt+ oil should do. I’ve had to add some more clicks to the compression and rebound so some slightly heavier weight oil is definitely the way to go.
@fbk- Yeh, I took the service intervals with a pinch of salt and was planning on giving them some love before a year but getting that dirt under the seal meant I had to do it sooner.
EDIT- The service intervals say you should do an oil change 1-2 a year but I’d do it every 3-4 months to be safe and make sure your fork is working at its best.Posted 4 years agoruscleMember
Just serviced my Deville 140’s with Motul 7.5wt oil as recommended by Loco and replaced seals with the SKF low friction ones, they are super plush now, better than when new. Found quite a bit of dirt in the grease under the seal on the left leg so will be dropping the lowers every few months. I’ve been riding these since Christmas on average once a week but didn’t get out at all through March.
You need a 21mm socket for undoing the foot nut, and to undo the rebound cap to put oil into top of leg is the same as a Fox fork (I think it’s 26mm socket)
Really easy service and well worth doing. Cheers for all previous posts to help.Posted 4 years agopashandMember
I also used Motul 7.5wt, if anything it feels like there is a bit less damping than with the original BOS oil. I’ve slightly increased my compression and rebound settings since the service. Slight wear on the air side stanchion for me too so I’ll be servicing them more regularly from now on.Posted 4 years agomindmap3Member
Bit of a thread resurrection, but the instructions above worked wonders although mine seem to different sized bolts in certain places.
I’m running 5w oil in the damper because that’s the lightest oil I had to hand. Likewise the oil in the sprung side us on 10w for now.
The spring side had no oil in it whatsoever, so I put 17ml in the bottom as per the post above. Luckily after a fair few grotty rides and a dry spring side there is no wear that I can see. I’ll do them again in a few months but will buy the correct weight Motul oils.
The forks feel smooth and are holding air so hopefully everything had gone to plan. The hardest part was getting the lowers back on.
Cheers again for posting the above info.Posted 4 years ago
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