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Bitubo dampers Cali 3 and others - help!

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italianmotor View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote italianmotor Quote  Post ReplyReply Direct Link To This Post Topic: Bitubo dampers Cali 3 and others - help!
    Posted: 10 Aug 2014 at 07:30
I've been helping a mate try and sort the forks on his California III. They are 40mm, with Bitubo dampers, and spring and damping adjustment on the top, and were used on other big Guzzis.

 I can't find out anywhere if these damper units are sealed, like the earlier simple T3/G5 ones, or aren't. Thing is, they are easy to take apart as they have threaded ends with o-rings. The damper mechanism all seems in good shape and operates ok - but, where the rod moves up and down in the damper body guided by the top cap, there seems to be no seal of any kind, so the oil, if it wanted to, could come out from there (although this is the top part of the damper, so when sat in the leg, sits highest). But to me it seems they were designed like this, and the damping goes on in the bottom of the leg with the plunger type mechanism and oil.

It suggests in Guzziology that these are rebuildable though I can't find any kits anywhere, and it also says they are very good units. So - can anyone say for sure that they are like this from new, or no, they definitely should be sealed, and are broken? Thanks...
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Jim Mac View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jim Mac Quote  Post ReplyReply Direct Link To This Post Posted: 10 Aug 2014 at 11:18
Is the oil not for lubtication only an doesnt actually play any part in the damping ?
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italianmotor View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote italianmotor Quote  Post ReplyReply Direct Link To This Post Posted: 11 Aug 2014 at 08:19
I'm not talking about the oil that goes in the fork leg as per the earlier bikes that is there just for lubrification, but oil inside the damper - but maybe it's the same oil - that's the problem, I don't know.
Is the damper meant to be sealed - or not?


Edited by italianmotor - 11 Aug 2014 at 08:20
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Ken-Guzzibear View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ken-Guzzibear Quote  Post ReplyReply Direct Link To This Post Posted: 11 Aug 2014 at 11:48
The normal front forks have damper units similar but larger than the items in rear shox, the ATF fluid in the legs is no more than a lube for the damper I do remember that SOME Bitubo legs have the air assist in them they have to be sealed these usually have a balance pipe and shrader valve on the top of the fork leg. They are "pressurised" via a bycycle type high pressure pump ...other than that tis all I know, By the way never had to do anything other than change the fork oil in the 76 V1000 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote doug061063 Quote  Post ReplyReply Direct Link To This Post Posted: 15 Nov 2014 at 23:35
hello
only joined today. I am following up on any info about the Bitubo cali 3 fork dampers.
I have a set of these that are leaking.
you can rebuild them {seals} kit are available from Sinse diese in Germany when they are in stock.
the issue is what sort of oil and how much goes into the damper.
any info would be helpfullSmile
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Ken-Guzzibear View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ken-Guzzibear Quote  Post ReplyReply Direct Link To This Post Posted: 16 Nov 2014 at 11:32
Welcome Doug ..... I do not know these forks BUT there are free downloadable manuals on the site "This old tractor" by Greg Bender scroll down and find the manual it is a brilliant site with all sorts of info re Guzzi
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italianmotor View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote italianmotor Quote  Post ReplyReply Direct Link To This Post Posted: 16 Nov 2014 at 13:07
In the end I ended up writing to Bitubo in Italy, and instead of simply telling me how much oil was meant to go in the dampers, they said 'look at the owner's manual' and that they were meant to be sealed dampers anyway.

Anyway, read somewhere, can't remember where, that 60cc of ATF will do the job, but I take no responsibility if this is incorrect. The mate who I was helping ended up buying new dampers in the end but has kept the others too.
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Ken-Guzzibear View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ken-Guzzibear Quote  Post ReplyReply Direct Link To This Post Posted: 16 Nov 2014 at 17:00
The older style front forks have sealed damplers in them that have ATF fluid to lube them no more bit the air assist ones I dunno IF the internal dampers fail I believe it requires new ones of which there are more then just the Guzzi ones to choose from. BUT the sealed ones do last a very long time the V1000 has the OE ones in them and it will be 39 come Jan 15 and has covered a fair few miles ...when I got it the top fork bolts were missing the bloke had never put them in so the top of the inner tubes must have been free ...amazing really
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Post Options Post Options   Thanks (1) Thanks(1)   Quote bark1tz Quote  Post ReplyReply Direct Link To This Post Posted: 25 Feb 2015 at 14:58
The Biturbo units are rebuildable and most if the parts can be sourced from generic suppoliers.First step,remove the fork springs,easily said but not easily done.The springs must be held in compression while the preload adjuster is removed.This is a 2 person job,unless you have a spring compression tool long enough to do the job.The adjuster is in 2 parts,the adjusting nut,which is held in by a small 2mm hex head bolt.and the adjusting mechanism,which screws into the top of the daamper rod and is retained by a locking nut.the rod has flat spotsfor an 11mm spanner,the locking nut is 13mm.undo the locking nut and the adjuster screws easily out of the rod( no spanner required.)All this has to be done with the spring compressed.We used a pair of vice grips clamped onto the top of the damper rod.This may mark the rod but if it's well away from the swept area,it shouldn't be a problem.The alloy cap can then be unscrewed from the body of the damper.Hold the damper in vice(remember it's hollow.) and vice grips on the cap.Inside the cap is an oil seal, a steel washer,then an o-ring with a nylon shape retainer inside it,then another steel washer on top of that.The whole lot is hekd in by a circlip.DON'T LOSE THE NYLON SPACER.If you do,you'll have to make one yourself,cause you can't buy them anywhere.
    The local Guzzi guru said to use 5wt oil in the damper and 15wt in the bottom of the fork leg.I used 2.5wt in both and it works just fine.There may be an official quantity of oil to put in the damper,but we discovered that one damper held more oil than other.Don't know why,there's no obvious reason.To overcome this we filled the dampers to the bottom of the internal thread,then replaced the damper rod,pushing it to the bottom of it's travel.Any excess oil overflows,then pulled the rod back to the top and screwed the cap back on.That way both dampers were full,regardless of capacity.If you think 2.5wt sounds a bit light,I'm 6'2" tall and I weigh 253 pounds,I had a tank bag, a box on the passenger seat and a top box full of gear with the damping adjustnent set on 45% and as I said,it works just fine.I know I haven't answered all the questions but it can be done,and when it is,you'll be rewarded with a very good front end.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Keef Mayhem Quote  Post ReplyReply Direct Link To This Post Posted: 26 Feb 2015 at 01:08
As  Bark1tz it can be done, it just confuses things when people keep referring to the earlier pattern forks with the sealed dampers located at the top of the stanchion.
I've refilled these 40mm bitubo units myself as I wanted more damping and used 5wt oil without any problem in my LeMans5. I didn't need to remove/replace the damper seals but they were simply standard garter spring single lipped seals I suspect you could pick up at any bearing factors.

However they can be modified, I had replacement springs fitted to mine as I run unlinked brakes and the front end was just way to soft, I also had the damper units modified  so they run in the same oil as the stanchion slides in, that works fine too.

Whatever you do, don't bother with the FAC air assisted replacement dampers, I tried them first and found them an expensive waste of time, they are still lying on the shelf in the garage somewhere



Edited by Keef Mayhem - 26 Feb 2015 at 01:13
So many bikes, so little time !
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italianmotor View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote italianmotor Quote  Post ReplyReply Direct Link To This Post Posted: 26 Feb 2015 at 09:25
Thanks for all the info  My mate ended up buying new dampers in the end because we couldn't find the right info and he needed the bike back on the road, but he has kept all the bits and will be able to rebuild them thanks to your help above. It's frustrating that Guzziology didn't go into any more detail than it did on these.
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