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2bims
Joined: 03 Apr 2010 Posts: 7292
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Posted: Sun Feb 05, 2017 9:41 pm Post subject: Bimota DB1 - Rear MArzocchi Shock |
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Hi Guys....Bit of a longshot....but with such a knowledgeable lot out there...maybe someone can help......Marzocchi rear single shock absorber....NOS....but from 1986...I need a new rear bump stop....item has a cabled knurled knob adjuster, with 3-position setting, evidently spring pre-load ring also.....item is gassed with a schraeder threaded adjuster to connect a pump to....Any idea what pressure it should be at...be it in bar or PSI...I have a Scott bicycle rear shock pump that is 0 - 40 bar adjustable, which is 0 - 600PSI...but have no idea what the pressure should be on a stock shock...BIke is a BImota DB1, 1986 vintage, and this was the standard rear shock they fitted...It seems that the BMW K100 of similar vintage also used a Marzocchi rear single shock if that helps, but unaware of what model the shock is they used....
HEres also a link on ebay to a NOS Marzocchi rear shock repair kit for a BMW K100 but as I've said..I've no idea if this is the same shock as the one I've got.... http://www.ebay.co.uk/itm/Marzocchi-Shock-Rebuild-kit-for-BMW-K100-part-number-850115-/232029048878?hash=item360602502e:g:w~AAAOxyu1FRkjH0 |
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quikduk
Joined: 13 Aug 2016 Posts: 287 Location: Southern California, USA
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Posted: Wed Feb 08, 2017 6:19 pm Post subject: |
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No idea but not too expensive of a gamble and the o-rings appear to be Viton. Do you have any suspension companies (like Race Tech here in So Cal) that can restore your shock?
Re: pressure, I would think that they are all nitrogen filled but unsure of how much pressure is standard. |
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quikduk
Joined: 13 Aug 2016 Posts: 287 Location: Southern California, USA
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Posted: Wed Feb 08, 2017 6:22 pm Post subject: |
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Oh. DON'T use "air". Maybe it has to do with the moisture content in regular "ambient" air versus the drier nitrogen gas. nitrogen refilling "should" require the use of a HP regulator but I am certainly not well versed in this arena.
I think the typ. pressures are 100-150psi but I wouldn't do it myself. Rebuilding is one thing but I'd have a suspension shop refill it.
Still looking for more info for you though... |
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quikduk
Joined: 13 Aug 2016 Posts: 287 Location: Southern California, USA
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quikduk
Joined: 13 Aug 2016 Posts: 287 Location: Southern California, USA
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quikduk
Joined: 13 Aug 2016 Posts: 287 Location: Southern California, USA
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Posted: Wed Feb 08, 2017 6:39 pm Post subject: |
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These guys (guy) have very good reports on their service and ability to make things work better than new. Granted it is in the States but they receive and send their work worldwide.
http://www.motocd.com/service/ |
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2bims
Joined: 03 Apr 2010 Posts: 7292
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Posted: Wed Feb 08, 2017 6:40 pm Post subject: |
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Cheers Duk...it kind of confirms what I have heard elsewhere...as I multipost on other forums to expand search criteria beyond us Bimota boys, a small bretheren that we are....Practicalsportbikes facebook being one such place.
The post is actually for another Forum member on here that is restoring a DB1....but personal issues means he's away so I said I would assist....Its actually a NOS item I bought from LoudBikeSteve in Canada when he had Db1 stock...but evidently 30 years old...and I sold it to the other nice fellow...along with some other spares on one of my big clearout sessions...then...when he pulled it out of storage the bumpstop magically disintegrated...I think he has big mice in his garage....So..felt guilty and liable to assist....others have said max 10 bar which is 150psi...and yeh...use nitrogen not air...Air is 78% Nitrogen...but 21% oxygen....Nitrogen has one of the lowest expansion rates under heat...Oxygen one of the highest...but all are compressible...and all expand...is about as much as I've gleaned |
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quikduk
Joined: 13 Aug 2016 Posts: 287 Location: Southern California, USA
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Quadrasuarass
Joined: 23 Aug 2013 Posts: 82 Location: New Zealand
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Posted: Wed Feb 08, 2017 8:53 pm Post subject: |
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I pulled the old Marzocchi out of my DB1 and have replaced it with a Maxton unit. I have the old shock laying around the place somewhere. I'll try and dig it out tonight to see if the bump stop can be re-used, it's of no use to me any more. However I fear it will have perished and not be of use. I can post a pic when I find it so you can see what it looks like. Meanwhile this is what I have dug up from photo archive
Cheers
Nigel
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Mike Jennings
Joined: 22 Mar 2008 Posts: 286 Location: England
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Posted: Sun Feb 26, 2017 4:23 pm Post subject: |
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Hello,
if the rubber bump stop has disintegrated, how do you fit a new one? Would you have to disassemble the shock?
Cheers, MikeJ |
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PaulDB2
Joined: 26 Apr 2014 Posts: 316 Location: Manchester
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Posted: Sun Feb 26, 2017 5:01 pm Post subject: |
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It looks like that is the only way. The bump stop itself is quite shallow. If one could find a flexible alternative it could be possible to cut it vertically then pass it around the 16mm piston rod and superglue it together./ I now have two shocks, my original alloy bodied one and a NOS steel bodied version, unfortunately the bump stop has disintegrated on both!
Resigned to have to get the shock rebuild. _________________ Bimota DB1, Bimota YB5, Bimota YB6 Exup, Bimota YB9 SR, Ducati NCR Replica, Moto Guzzi 750 S3, Honda CR750 race replica, Seeley-Suzuki TR500 |
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Mike Jennings
Joined: 22 Mar 2008 Posts: 286 Location: England
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Posted: Sun Feb 26, 2017 5:37 pm Post subject: |
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Hello,
you could try 'rubber bump stop' on ebay in the vehicles section. They seem to have quite a few but you'd have to check the size,
Cheers, MikeJ |
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Bud977
Joined: 03 Mar 2013 Posts: 525 Location: Sydney
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Posted: Sun Feb 26, 2017 8:20 pm Post subject: |
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You have to remove the eye end of the shock to replace the bump stop rubber. Glueing a split rubber in place wouldn't last one speed hump. |
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DB1 860
Joined: 23 Mar 2014 Posts: 177 Location: Sydney
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Posted: Tue Feb 28, 2017 10:13 pm Post subject: |
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So can these rear shocks be pulled apart and serviced ?
I've been thinking of getting mine done as its not been touched since new. |
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Bud977
Joined: 03 Mar 2013 Posts: 525 Location: Sydney
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Posted: Wed Mar 01, 2017 7:17 pm Post subject: |
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It sure looks like it. You could try Frank Pons to rebuild the shock. He's old school and can fix anything. Let me know if you'd like his details. |
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