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Prsv
Premium Member Joined: 29 Jan 2016 Location: Fareham Status: Offline Points: 555 |
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Posted: 14 Feb 2016 at 19:49 |
Serviced my factory ohlins today spacer off spring still in took oil level before draining 100 mm. flushed with parafin let them drain for a good hour, put 500 cc oil in each leg and only had 130 mm level spring in fully compressed damper rod down. Manual states 500 cc should give 85 mm, added 50 cc approx went for 95 mm level.
Am I missing something or does that sound about right.
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Spoonz
Admins Group Joined: 11 Feb 2008 Location: North Devon Status: Offline Points: 10726 |
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Last time I did ohlins I used more than 500cc in each leg so I wouldn't read too much into the amount as long as it's not hugely wrong.
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Prsv
Premium Member Joined: 29 Jan 2016 Location: Fareham Status: Offline Points: 555 |
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Ahh didn't know damper rod had to be up taking displacement into account probably would of been nearer 100 mm then. Have you ever replaced bushes inside fork had fair bit of play on one.
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Spoonz
Admins Group Joined: 11 Feb 2008 Location: North Devon Status: Offline Points: 10726 |
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I replaced the lower bushes on mine once as I could feel a knocking in one leg but it turned out not to be the bushes in the end. The lower ones are fairly easy as access is pretty good.
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Prsv
Premium Member Joined: 29 Jan 2016 Location: Fareham Status: Offline Points: 555 |
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What was the knocking, I could hear play thought it was coming from top bush when moving fork bottom and holding tube. Put magnetic dial gauge on had 0.08 mm play, when stripped bushes looked good no wear marks put it down to oil clearance.
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Spoonz
Admins Group Joined: 11 Feb 2008 Location: North Devon Status: Offline Points: 10726 |
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It was coming from the top cap which was incorrectly shimmed from the factory.
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Prsv
Premium Member Joined: 29 Jan 2016 Location: Fareham Status: Offline Points: 555 |
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So what air gap is a good base setting in ohlins then. The springs
had 2 marks lines on face of springs no other markings 242 mm long thinking they are not standard or is that how ohlins marks them. |
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Spoonz
Admins Group Joined: 11 Feb 2008 Location: North Devon Status: Offline Points: 10726 |
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Depends on the individual really. The smaller the air gap the faster the damping rate ramps up as the fork compresses. If you have too much oil the damping ramps up way to early and will over ride your compression damping way before the end of travel, too little and the forks won't ramp up enough and will bottom.
Getting that happy medium depends on your weight and riding style and the oil thickness. Best just to experiment and find a best setting. for me I found the oem air gap of 85mm meant I couldn't get anywhere near full travel even with minimal compression damping. If I'm honest I prefer the radial showa forks to the Ohlins from a road use point of view. The Ohlins are a bit more track focused and a bit harsh on the road for me as they come from the factory.
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m9rko
Premium Member Joined: 10 Sep 2012 Location: edinburgh Status: Offline Points: 2080 |
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I serviced mine recently and went for 85mm gap (everything installed except top washer, damper rod all the way in). I was told by some reputable people that this was a good base setting I used just over 500ml in each fork leg.
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www.apriliaperformance.co.uk
www.apriliaforum.co.uk www.apriliaownersclub.co.uk |
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Prsv
Premium Member Joined: 29 Jan 2016 Location: Fareham Status: Offline Points: 555 |
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like you found them harsh on the road but working well, nearly full travel on a good ride. Had smear of oil from one leg mot due so changed seals went for 5wt oil didn't want damping any stiffer and kept air gap same less 5mm allowing for any oil lost. Do you think springs are OE like said, have 2 edge of file marks on machined face of spring ?
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m9rko
Premium Member Joined: 10 Sep 2012 Location: edinburgh Status: Offline Points: 2080 |
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After a quick search it looks like 2 etched marks means they are standard in a later gen 1 radial bike, and are 10.0 N/mm spring rate
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www.apriliaperformance.co.uk
www.apriliaforum.co.uk www.apriliaownersclub.co.uk |
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Prsv
Premium Member Joined: 29 Jan 2016 Location: Fareham Status: Offline Points: 555 |
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M9rko did you take air gap before draining mine being 100mm went in the midle ish 95mm manual sates 85mm. as spoons says if not getting nearly full travel go with more air gap.
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Spoonz
Admins Group Joined: 11 Feb 2008 Location: North Devon Status: Offline Points: 10726 |
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M9arko would have had about 90mm air gap if the rod was down. It raises the oil level when in the bath which would have dropped again once it was raised and attached to the cap.
I went with 5wt oil also. Even with an increased air gap and lighter oil they still never got close to bottoming but were less harsh on big hits. Had I still got ohlins I think I would have experimented with shimming or a lighter bypass spring for the real big hits..
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Prsv
Premium Member Joined: 29 Jan 2016 Location: Fareham Status: Offline Points: 555 |
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m9rko they are gen 2 factory radial forks so should be standard then thanks.
spoons thanks for the knowledge your a credit to this forum. |
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m9rko
Premium Member Joined: 10 Sep 2012 Location: edinburgh Status: Offline Points: 2080 |
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If there's 2 etched line's I don't think they are standard springs.. This is stolen from another forum (amauri on AF1)
"The first generation Ohlins/Aprilia radial fork # FG8900 & 8901 came with .95 N/mm springs. Somewhere late in 2004 or early 05 they updated to the FG8902 and later 8903, those later forks came with 1.0 springs, upgraded seals and a small change in the compression shim stack If you remove the original fork spring and look at the ends, you should see some markings. Aprilia, Ducati and other OEM Ohlins fork springs do not have any numbered markings. They are marked instead with a hand etched line or lines. The .95 OEM springs are not marked at all (2003 – 2004). The 1.0 OEM springs are marked with one line (2004 – 2009). The 1.05 OEM springs (RSV4) are marked with two engraved lines. Springs you buy from Ohlins will have a numeric laser etching designating the type and rate." Hope that helps |
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www.apriliaperformance.co.uk
www.apriliaforum.co.uk www.apriliaownersclub.co.uk |
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Spoonz
Admins Group Joined: 11 Feb 2008 Location: North Devon Status: Offline Points: 10726 |
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As a aid to understanding the air gap effect on damping, this is from the Ohlins manual showing the effect of oil height on the rising rate of the damping. The chart only shows a small range but the rise is fairly linear for each 10mm reduction in air gap so you can approx work out where the rate would be at 85mm air gap. It does highlight how quickly in your travel that your compression can be determined by your air gap than the compression valving in your fork.
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Golightly
Premium Member Joined: 09 Jul 2015 Location: Portsmouth Status: Offline Points: 137 |
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does the 85mm air gap apply to gen 1 non radial Ohlins please?
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Your Welcome
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Spoonz
Admins Group Joined: 11 Feb 2008 Location: North Devon Status: Offline Points: 10726 |
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If you want the stock setting yes.
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philmille
Premium Member Joined: 11 Feb 2008 Location: Colchester Status: Offline Points: 46 |
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I had mine serviced by the firm in Stowmarket 2 years ago, and now one the the seals has a leak, tried the Sealmate tool, but that hasn't helped. Any ideas? how come they keep going????
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PhilMille
01 RSVR The World is divided into armed camps ready to commit genocide just because we can't agree on whose fairy tales to believe, in the end, Religon will kill us all. Ed Krebs |
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Spoonz
Admins Group Joined: 11 Feb 2008 Location: North Devon Status: Offline Points: 10726 |
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They may not have used the newer multi lipped seals or there may be mark from a stone chip that damages the seal.
Ohlins seals also don't like being dry, they harden or stick to the stanchion. If the bike is parked up for any length of time, bounce the front suspension as it coats the inner lips with a thin oil film when you do that. |
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BOL D'OR
Moto GP Alien Joined: 02 Sep 2013 Location: Aberdeen Status: Offline Points: 269 |
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I recently had my Ohlins serviced by MH racing.
Not cheap when you factor in postage/packing from Aberdeen + insurance in case they get lost/damaged. I wish I'd asked him if he uses these newer multi-lipped seals.
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philmille
Premium Member Joined: 11 Feb 2008 Location: Colchester Status: Offline Points: 46 |
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Cheers Spoonz, going to get the seals replaced by the same firm, MCT, then make sure they don't dry out....
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PhilMille
01 RSVR The World is divided into armed camps ready to commit genocide just because we can't agree on whose fairy tales to believe, in the end, Religon will kill us all. Ed Krebs |
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