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General Category => General Discussion => Topic started by: amamet on December 28, 2019, 08:45:23 PM

Title: Anyone have experience refilling FAC dampers?
Post by: amamet on December 28, 2019, 08:45:23 PM
Need to refill my fac dampers on my lemans 1 and cant seem to find the procedure or any information to do so.
Any help is appreciated
Thx
Allen
Title: Re: Anyone have experience refilling FAC dampers?
Post by: Kiwi_Roy on December 29, 2019, 03:56:30 AM
I assume you meant rear dampers.
I did a quick search for FAC shocks and came up empty
Are they gas filled, that would be a problem.

Hang on, here we go
http://www.thisoldtractor.com/moto_guzzi_tonti_fac_damper_rebuild_information.html
Title: Re: Anyone have experience refilling FAC dampers?
Post by: amamet on December 29, 2019, 07:34:01 AM
really surprised no-one has chimed in on this.  they are front dampers for my lemans 1 forks.  can't seem to find any manufacturer info online either.  I guess ill just figure it out on my own?  with one held vertically I started with 70ml of 10 wt fork oil, after burping the damper, the rod "fell" about a half inch till the damping effect slowly lowered the rod.  I added @5 more ml until there was no free fall of the rod.  I guess thats it?
Title: Re: Anyone have experience refilling FAC dampers?
Post by: chuck peterson on December 29, 2019, 08:11:20 AM
Are you talking about replacing fork oil? Or opening the sealed FAC damper that’s inside the fork?

If its fork oil, typically ATF for lubrication in Guzzi, you’ll need to check specs. I know for a Convert, its not much. 100ml or less if I forget. Overfilled and the fork locks up after a short travel.

The FAC’s were fantastic on a heavy convert for me, but I didn’t find any need to rebuild it after 50k. Don’t remember seeing any way in or out of the sealed damper without destroying something


Title: Re: Anyone have experience refilling FAC dampers?
Post by: amamet on December 29, 2019, 08:29:56 AM
hey chuck, yes the damper unit.  the top just unscrews. when I was disassembling the forks, I figured id change to oil in there too.  didn't realize there is no information on this anywhere , here included
Title: Re: Anyone have experience refilling FAC dampers?
Post by: amamet on December 29, 2019, 08:34:24 AM
just noticed your in new haven, chuck,  my girlfriends daughter just committed to univ of new haven,  we had a pretty bad experience at frank pepes a few weeks ago.  were both pizza families.  any other recommendations?  or should we try again.  im just assuming everyone enjoys pizza as much as we do :)

Allen
Title: Re: Anyone have experience refilling FAC dampers?
Post by: amamet on December 29, 2019, 04:42:16 PM
Alright, so nobody know how to refill these things, does anyone know how to find the manufacturer?  Somebody is making them so they have to know how to refill them. Google is getting me nowhere in finding the company
Title: Re: Anyone have experience refilling FAC dampers?
Post by: John Croucher on December 29, 2019, 05:31:14 PM
Alright, so nobody know how to refill these things, does anyone know how to find the manufacturer?  Somebody is making them so they have to know how to refill them. Google is getting me nowhere in finding the company

I used your method once.  I rinsed the dampers out with  naptha, drained, added oil.  I used teflon tape on the screws.  seemed to work. 

The set i worked on did not have a drain/fill hole.  I drilled a hole into the cylinder on the end where the top mounting
(https://i.ibb.co/VL2njcc/s-l1000-jpg-cf.jpg) (https://ibb.co/VL2njcc)
Title: Re: Anyone have experience refilling FAC dampers?
Post by: Roebling3 on December 29, 2019, 06:00:52 PM
Sorry I'm no help with dampers, but

Modern Apizza 874 State Street New Haven, CT Since 1934!!! Wood Fired.
If that's not modern enough I cannot help. There's a bakery nearby for dessert'
    Cannolis, of course.  Enjoy. R3~
Title: Re: Anyone have experience refilling FAC dampers?
Post by: amamet on December 29, 2019, 06:11:20 PM
I’ve heard good things about modern apizza. I’m hoping my bad experience was just due to a busy night. I’ll have plenty of opportunities in the next 4 years to go back
Title: Re: Anyone have experience refilling FAC dampers?
Post by: Antietam Classic Cycle on December 29, 2019, 06:16:09 PM
I used your method once.  I rinsed the dampers out with  naptha, drained, added oil.  I used teflon tape on the screws.  seemed to work. 

The set i worked on did not have a drain/fill hole.  I drilled a hole into the cylinder on the end where the top mounting
(https://i.ibb.co/VL2njcc/s-l1000-jpg-cf.jpg) (https://ibb.co/VL2njcc)


I think you mean my method (although it's not really "mine" - I saw it somewhere or someone passed it along to me long ago). None of them have drain holes, I drill one in the same location as you did. First set I ever refilled was on my '79 SP back in '85 - cured it's "wallow in bumpy turns" issue. My Convert is running dampers I refilled - the first few thousand miles they were very firm, but have now "broken in" again and the ride is still slightly firm but well controlled.
Title: Re: Anyone have experience refilling FAC dampers?
Post by: Kiwi_Roy on December 29, 2019, 06:48:50 PM
What was wrong with the info I posted from Greg Bender's site?
Title: Re: Anyone have experience refilling FAC dampers?
Post by: amamet on December 29, 2019, 06:58:34 PM
Nothing per se, but the amount of oil suggested left a section of the damper free falling before damping took effect. I would love to find manufacturers info on these dampers.  There has to be info out there. Did I put in enough oil? Too much? Is too much an issue or not? 
Title: Re: Anyone have experience refilling FAC dampers?
Post by: Tony F on December 29, 2019, 07:57:26 PM
I think you mean my method (although it's not really "mine" - I saw it somewhere or someone passed it along to me long ago). None of them have drain holes, I drill one in the same location as you did. First set I ever refilled was on my '79 SP back in '85 - cured it's "wallow in bumpy turns" issue. My Convert is running dampers I refilled - the first few thousand miles they were very firm, but have now "broken in" again and the ride is still slightly firm but well controlled.

I used this method also. On the dampers from my '79 SP1000 back in 1981 in fact. I read about in a UK Moto Guzzi Club magazine. Its success depends on the condition of the seals in the dampers. If you don't get the same amount of oil out of both dampers that flags a failed seal (or the same amount could flag failed seals in both dampers). It worked well for me but the seal leaked slowly in one of the dampers so it wasn't long lasting. I replaced them with aftermarket dampers when they first became available.

Tony
Title: Re: Anyone have experience refilling FAC dampers?
Post by: chuck peterson on December 30, 2019, 07:40:04 AM
just noticed your in new haven, chuck,  my girlfriends daughter just committed to univ of new haven,  we had a pretty bad experience at frank pepes a few weeks ago.  were both pizza families.  any other recommendations?  or should we try again.  im just assuming everyone enjoys pizza as much as we do :)

Allen

Choosing between Frank Pepe or Sally's is similar to Yankees vs Redsox around here. (See carb vs efi, tire pressures, synthetic vs Dino) If your bad experience was a 2 hour wait, well that's just normal. But the Pepe's clam, broccoli and garlic w white sauce pizza is to die for.

We had a Connecticut guzzi group meet at Modern Pizza....eh..
Title: Re: Anyone have experience refilling FAC dampers?
Post by: Chuck in Indiana on December 30, 2019, 10:09:41 AM
Nothing per se, but the amount of oil suggested left a section of the damper free falling before damping took effect. I would love to find manufacturers info on these dampers.  There has to be info out there. Did I put in enough oil? Too much? Is too much an issue or not?

Too much is definitely an issue. They will lock up.
Title: Re: Anyone have experience refilling FAC dampers?
Post by: wirespokes on December 30, 2019, 01:27:25 PM
I've had an oil expert tell me that ATF is somewhere around 15-20 weight - depending on which ATF.

And then tests have also shown that manufacturers of fork oil don't have any standard measure of viscosity. One's 10wt might be less or more viscous than another's 10wt.

With all the variables it would be nice knowing what viscosity oil to use, and specifically which brand and weight worked well for you.