Ducati Monster Forum

Hello I hope everyone is doing alright,  enjoying the summer  [thumbsup]
had a question abt ohlins forks . I recently bought a 03 999r with very low miles and had a fork leak .
I replaced the fork seals , drained all the fluid and added new one according to book specs 480ml per leg .
My question is : when I compress the fork down and release it right the way it makes a sound like there is air coming in and out . Or when I hit a bump it sounds the same . This sound was there even before I did the work to it . Is it normal for ohlins ? Thank you in advance

When you replaced the oil did you raise and lower the damper rod to get oil into the valve?

yes I did . I even poured oil in there when the damping rod was out .

Could you feel resistance to the oil as you raised and lowered it?

yes

I've never noticed an air sound on any Ohlins units.

its more like squishy sound . I've read lots of threads abt it today,
lots of ppl have it but none of them wrote anything abt solving this issue. .
Like I said it was there before I replaced the seals and is still there. .. I rode the bike for 200 miles last weekend .. the noise was there when I started riding .  Afterwards I don't remember if it went away or not  once the oil warmed up.  It doesn't bother me and the fork works well. . I just want to know what causes that for problems in the future. .

I suppose it would depend on what's causing it. Like I said I never noticed any sound when compressing or releasing an Ohlins forked bike.

You might have a suspension guy put an ear to it.

sounds good . Thank you

So here I am playing with the fork setup. .
I losen the bottom adjusters i guess they r called rebound , all the way with the top screws (preload) at 15 clicks and its still doing that squishy sound ... however when I tie the top screws all the way..the sound is not there .. if I go back two clicks it starts making the sound..  so I realized that its smth with the preload adjustment .

Clicks?  That would be damping (i.e, compression setting).  Preload is usually measured in turns and requires a wrench.

I'm no ohlins expert, but it's not uncommon for dampers to make squishy noises as the hydraulic fluid passes through shim stacks or orifices or bypasses.  If your fluid type/height is correct, you have proper adjustable damping action, and it's not a scraping noise, I think you are good to go.

BK

yes good pointer. I was in a hurry when I was typing .
So I do not think its a scrapping noise .. its just the sound of the fluid moving .. like I said before it was there even before I changed the seals . Ill go check out ohlins equipped bikes in a dealership and ill check couple of my buddies bikes as well , and go from there ..

Did you pour in 480 ml of oil or measure actual oil level (less springs)?  If you just dumped in new oil you almost certainly have too much in the forks.

That said, too much oil probably wouldn't cause what you're experiencing.  Could you have torn an o-ring on one of the fork caps?  Is the noise new since your fork seal change, or was it there prior to the change?

i poured 480ml of oil in there.. i didnt measure the level. is that necessary ?
you may be right abt the fork cap oring .. i noticed a little oil on top of the fork cap where the preload screw is , right around the blue scew. the other day . are you talking abt the oring that is around the fork cap ? or there is an oring on the inside of the preload scew?
yes the noise was there before i replaced the seals.

Sorry for the late reply, I've been out of town for the last week.

Level is the standard thing to measure, as air volume remaining inside the fork is the metric you really care about.  The air left inside the fork leg acts as a progressive spring, so it has a drastic effect on handling.  You want to measure with the leg fully collapsed and the spring removed.  The level should be around 155mm if I remember correctly, but it'd be worth a call to Dan Kyle to check if there's not a level published in the service manual (I don't have a manual for the R).

I was talking about the o-ring that seals the fork cap to the fork stanchion.  There are two others.  There is also an o-ring that seals the preload adjuster to the cap, and another that seals the rebound adjuster to the preload adjuster.  It'd be worth inspecting all three for damage.  This would definitely cause your "squish" noise as air passes the fouled o-ring on the compression stroke and is sucked back in on the rebound stroke.

See http://www.zupin.de/uploads/tx_userzupindownloads/OM_07282-02.pdf (http://www.zupin.de/uploads/tx_userzupindownloads/OM_07282-02.pdf) for a 43 R&T manual including exploded diagrams on page 7.  Ohlins' preferred method of measuring oil level is with the springs still in, but every other manufacturer or service technician I've ever spoken with (including myself) does this with springs out, and that's how numbers are generally published.

no worries..
I completely understand what u r saying. I still havent tested this bike on the twisties so idk how it performs yet. .  (Busy with work)
However I went out for 200miles after I did the fork seals and had no problems with anything .. the forks deep in equally.. I have straps onnboth forks that way i see the travel .
Now my question to u is : can I keep them like that for the rest of the season? Is there anything in there thats going to be damaged if the oil level is not set at 155mm ? Other than performance. I really dont have the time to redo them . Let me know . Thx