Author Topic: Oil cavitation in the forks  (Read 2184 times)

bob

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Oil cavitation in the forks
« on: March 30, 2014, 06:46:05 PM »
On long fast trails I'm finding the stock suspension is struggling to cope and after 10 or 15 miles on a rough track the forks start behaving like a jackhammer. I think this is probably air bubbles building up in the oil. Has anybody experienced this and has anybody experimented with fork oil weight or settings?

Lotus54

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Re: Oil cavitation in the forks
« Reply #1 on: March 31, 2014, 12:24:05 AM »
I have not.
But I have the damping set to minimum.
I also get back quite a bit on faster stuff- keeping the front end light and let the rear do the work (ok- my legs also)
2014 OSSA Explorer

BigBadDon

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Re: Oil cavitation in the forks
« Reply #2 on: April 01, 2014, 05:06:24 AM »
How about a set of fork bleeders?

bob

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Re: Oil cavitation in the forks
« Reply #3 on: April 01, 2014, 08:41:27 AM »
Never heard of 'em Don, what do they do ? I notice there is an air bleed valve on the Explorer forks but I'm not sure what its purpose is.

BigBadDon

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Re: Oil cavitation in the forks
« Reply #4 on: April 01, 2014, 01:58:55 PM »
They take the place of the air bleed screw at the top of the fork.  They are a manual push botton to let out excess are or let in extra air so the forks are normalized to atmospheric pressure.  I have them because I am constantly tying down my bike and compressing the forks - I just dont want to prematurely wear out the seals.

So will they work to help fork oil cavitation?  No clue.

http://www.motosport.com/dirtbike/fork-air-bleeders


On a similar note:  I really wish I bought the explorer with the marcozzi forks and ohlin rear.  I find the front forks pretty crappy.  I looked into upgrading but it was going to be $1500USD.  Yikes.

bob

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Re: Oil cavitation in the forks
« Reply #5 on: April 01, 2014, 03:04:27 PM »
You and me both Don, I bought my 2014 Explorer and the importer also offered me a brand new 2012 model built up from a trials bike with the expensive suspension, tubeless rear etc but it was 20% more than the 2014 bike [which I got a good deal on] and I felt it would be wiser to but the later model which in theory should have been debugged. I felt that for trail use I wouldn't really need the fancy suspension but now I'm not so sure.
I really like my Explorer but its going to take some development to get it to where I want it.

Lotus54

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Re: Oil cavitation in the forks
« Reply #6 on: April 01, 2014, 06:33:54 PM »
I was going to order mine with the  trials suspension, but it was going to take a lot longer and I was impatient to get the bike!
  I'm certainly not sorry I got the 2014 Explorer, most of what I heard complaints about were fixed.
I ordered the Ohlins rear recently, we will see how much difference it makes. (Sold my KTM and have some extra for goodies).

Forks seem ok for the  travel for me- but certainly not wonderful. But I didn't expect them to I be great for fast trails.
They seem much the same as the forks on my old GasGas 280 TXT Pro.

OSSA listed inverted forks as an option originally, but I don't know if they ever really sold any.
2014 OSSA Explorer

bob

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Re: Oil cavitation in the forks
« Reply #7 on: April 02, 2014, 07:03:04 AM »
I've wound the damping right back but it doesn't seem to have much effect one way or another. I'm going to try some 2.5w oil this week and we'll see if that improves matters.


bob

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Re: Oil cavitation in the forks
« Reply #8 on: April 09, 2014, 08:36:56 AM »
I need to add something to the previous post, when I said I could detect no difference when I wound the damping back I should have qualified it by adding that I couldn't detect any difference in damping when bouncing up and down on the bike in the garage or on a quick blat up the road. Since then I've been out on some long trail rides and the jackhammer sensation has almost [not quite] gone away. I've yet to install the 2.5w oil , we'll see how we get on with that.
I've just done an Explorer related post on my blog...

http://adventurerideblog.wordpress.com/

Lotus54

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Re: Oil cavitation in the forks
« Reply #9 on: April 10, 2014, 01:24:31 AM »
Strange, I have about 63 hours on mine and almost nothing has failed or broken.
No plastics issues, always works great.

Of course, it was about 58 hours before I dropped it even- but I do ride some rather rugged routes.
 
Oh yeah, I found an O ring to fit in the fuel cap- doesn't leak at all now!

Thanks for posting your blog.

Mark
2014 OSSA Explorer

AM407

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Re: Oil cavitation in the forks
« Reply #10 on: April 11, 2014, 01:43:18 AM »
Good tip on the O-ring, I'll give it a try. Ours leaks pretty bad, but I always thought it was just fuel venting through the hole in the cap.