FAC Damper Upgrade 1980 1000SP - Opinions Wanted

[CT Dharma]

While I have my forks apart for new seals I'm considering upgrading to new FAC dampers with progressive rate springs. A little background - it's an '80 1000SP [50k] which I bought new when I was a lot younger. Forks have never been upgraded except for previous seal replacement. Suspension seems soft though that could also be attributed to me being 30lbs heavier than the 1980 version of myself or comparing to much more modern machines in the garage. There are no obvious defects on the original parts except for plating loss on one of the dampers. My question is will I see any significant improvement by spending the money to upgrade to more modern components while I have the forks apart? Would appreciate thoughts for others who have gone down this road before [pun intended].

Thanks.

[arveno]

I put FAC dumpers on my 1980 Sp two years ago... 26k miles , yes i noticed a big difference from stock.
A lot more stable and stiff front end.
I was told that it takes some miles to beak in and lose the stiffness .... i destroyed the bike before break it in so i will never know.

If you ask me : yes worth the money , i also put a tarozzi fork brace.

I miss that bike.

[huub]

personally i would just buy new original dampers, the aftermarket stuff ,is slightly better ,but not enough to be worth the extra investment.
after 35 years the originals dampers are probably shot.
instead of progressive springs you can add a couple of spacers to raise the ride height and more oil, the air chamber in the forks acts as a progressive spring , adding more oil reduces the air volume and stiffens the air spring.

[Chuck in Indiana]

Different strokes (pun intended) for different folks. I'd put the FACs in them. 

[Antietam Classic Cycle]

There are no obvious defects on the original parts except for plating loss on one of the dampers.

Do you mean plating loss on one of the fork tubes? Same thing happeded to the SP that I just rebuilt the front end on for a customer. Two new fork tubes, FAC dampers, Wirth springs, new seals and dust wipers, Tarozzi brace. Completely changed the way the front forks worked. Went from flacid to firm.  The 150 miles I put on it, they were a bit too firm for my liking, but I know from experience they "break-in" and ride much better.

I bought the brace from Fast from the Past: http://www.fastfromthepast.com/28-0010 and it made a noticeable improvement in rigidity. With the brace loose, I could tweek the front end pretty good when it was on the lift, clamped in the wheel vise. Brace screws tightened up and it was much more stiff.

One tip regarding FAC installation: don't use the hex nut that they provide to lock the damper rod to the extension rod. It's a 13 mm hex and doesn't fit down through the coils of the springs without rubbing. Reuse the 11 mm hex nuts from the old dampers for best results.

[CT Dharma]

Do you mean plating loss on one of the fork tubes? Same thing happeded to the SP that I just rebuilt the front end on for a customer. Two new fork tubes, FAC dampers, Wirth springs, new seals and dust wipers, Tarozzi brace. Completely changed the way the front forks worked. Went from flacid to firm.  The 150 miles I put on it, they were a bit too firm for my liking, but I know from experience they "break-in" and ride much better.

I bought the brace from Fast from the Past: http://www.fastfromthepast.com/28-0010 and it made a noticeable improvement in rigidity. With the brace loose, I could tweek the front end pretty good when it was on the lift, clamped in the wheel vise. Brace screws tightened up and it was much more stiff.

One tip regarding FAC installation: don't use the hex nut that they provide to lock the damper rod to the extension rod. It's a 13 mm hex and doesn't fit down through the coils of the springs without rubbing. Reuse the 11 mm hex nuts from the old dampers for best results.

No it's the damper, the 'plating' flaked off on one only. The fork tubes are in great shape. Seems like the fork brace is another important piece. Might you have a picture of the SP with the fork brace installed?  Thanks for the information.

[Antietam Classic Cycle]

No it's the damper, the 'plating' flaked off on one only. The fork tubes are in great shape. Seems like the fork brace is another important piece. Might you have a picture of the SP with the fork brace installed?  Thanks for the information.

I didn't take many photos of that job, this is the only one that shows the bike with the brace on.

[SED]

The LMIII (1983) has cartridge dampers and two piece springs.  I think the SP1000 has the dampers, but not sure of the two piece springs.

7 years ago I replaced the longer (upper) springs using those recommended in Guzziology (yellow paint?) and they corrected the ride height.  Don't remember having any other strong impressions - just seemed to work right. 


Last spring I replaced the original dampers with FACs and noticed a big difference.  The rebound damping on the OEM cartridges was shot so the FACs made the bike feel more "planted" on the road - and the front didn't bob up so quick from a stop.  FACs also transformed the handling of my Monza too.  Both bikes feel less "nervous" on uneven surfaces. 



Disassembled the OEM dampers on the LMIII (and Monza).  OEM dampers have an air bladder with a projection on the end that pushes into an oil port.  Apparently increasing the air pressure slows the passage of oil through the port increasing the damping (compression damping I think).  The air bladder also keeps the oil and air separate so there is less opportunity for the oil to foam when the damper is working hard.  I found the old air bladders were deformed asymmetrically and didn't seat in the port - in fact it looked like the bladders were slightly longer than the space needed so had deformed when installed at the factory.  I'd bet that the OEM bladders lose their ability to seat in a very few years after manufacture due to the asymmetric deformation.  Additionally one bladder had a hole so no longer kept air out of the oil.  I wouldn't use OEM dampers - especially ones that have been sitting on a shelf for years.  I found the FAC dampers were something like $20 more than OEM dampers.



A fork brace is a big improvement.  I noticed the difference on the first 90 degree corner I rolled through.  The bike seemed to turn into the corner easier and follow the line better.  And this was at about 15 mph from one city street to another. 

The LMIII and Monza forks are very similar and I blogged rebuilding the Monza forks on WG.  You may find it helpful: http://wildguzzi.com/forum/index.php?topic=75441.0

Hint: it's much faster to refill the fork legs with 70cc fork oil if you use a syringe and inject it from the bottom rather than dribbling it down between the damper and the inside of the fork leg.

[SED]

While I have my forks apart for new seals I'm considering upgrading to new FAC dampers with progressive rate springs. A little background - it's an '80 1000SP [50k] which I bought new when I was a lot younger.

BTW, I've seen a couple posts concerning trouble or disappointment with progressive springs.

Bought new - Cool history!  And Charlie's SP looks great too.

[redrider90]

BTW, I've seen a couple posts concerning trouble or disappointment with progressive springs.

Bought new - Cool history!  And Charlie's SP looks great too.

I replaced worn out dampers with Bitubos and then added Wirth progressive springs on my 90 Mille. Before the change I could roll off the throttle and the front end would drop 2" at 50 MPH. After the change no drop at all and better yet it sure made a much better handling bike in the curves.
The only issue with the progressives is on an old concrete super slab with those expansion joints every 40' of so. It can be a bit jolting. I always expected the progressives to break in and soften slightly but after 30K on them they are still tight.

[eldoroddo]

I just had FAC dampers and progressive springs installed last week on my CX100. Haven't put on a fork brace yet.
Definitely stiffer. I'm about 215lbs.

[Aaron D.]

On various early Tontis I've obviously ridden stock, I've done FAC dampers only, and FAC plus springs and a Tarozzi brace.

I would do all three if I were in the forks already. The dampers-only was much better than the stockers (which were so shot at less than 20K miles it felt like it would wheelie at the end of a hard stop) but the springs gave a great feel all around.

[Stevex]

I was going down the FAC route on my LM2 but was advised of the original damper re oil option.
As the original type dampers were leak free, I re oiled them with a good quality 5w fork oil and it worked for me.
Checking the original 2 springs per fork assembly, I also found the longer pair has 'shrunk' by about 15mm so had some spacers made up to return the pre load to standard.
I'd also previously replaced the horrendously heavy original fork mounted fairing with a light as a feather AirTech replica.
The lack of weight over the front end obviously helps a lot and I've finally found a cast aluminium fork brace which I hope will add much needed rigidity to the forks.

[blackcat]

I replaced worn out dampers with Bitubos and then added Wirth progressive springs on my 90 Mille.

The FAC's on my CX went (too much air) and I replaced them with Bitubo's and Wirth springs. The FAC's had the stock springs so it isn't an exact comparison but I like the Bitubo's even though some said they were junk. Mine have been quite good, but I have no idea if they are still available.

[CT Dharma]

I didn't take many photos of that job, this is the only one that shows the bike with the brace on.

Thanks for the information; beautiful bike!

[CT Dharma]

The LMIII (1983) has cartridge dampers and two piece springs.  I think the SP1000 has the dampers, but not sure of the two piece springs.

7 years ago I replaced the longer (upper) springs using those recommended in Guzziology (yellow paint?) and they corrected the ride height.  Don't remember having any other strong impressions - just seemed to work right. 


Last spring I replaced the original dampers with FACs and noticed a big difference.  The rebound damping on the OEM cartridges was shot so the FACs made the bike feel more "planted" on the road - and the front didn't bob up so quick from a stop.  FACs also transformed the handling of my Monza too.  Both bikes feel less "nervous" on uneven surfaces. 



Disassembled the OEM dampers on the LMIII (and Monza).  OEM dampers have an air bladder with a projection on the end that pushes into an oil port.  Apparently increasing the air pressure slows the passage of oil through the port increasing the damping (compression damping I think).  The air bladder also keeps the oil and air separate so there is less opportunity for the oil to foam when the damper is working hard.  I found the old air bladders were deformed asymmetrically and didn't seat in the port - in fact it looked like the bladders were slightly longer than the space needed so had deformed when installed at the factory.  I'd bet that the OEM bladders lose their ability to seat in a very few years after manufacture due to the asymmetric deformation.  Additionally one bladder had a hole so no longer kept air out of the oil.  I wouldn't use OEM dampers - especially ones that have been sitting on a shelf for years.  I found the FAC dampers were something like $20 more than OEM dampers.



A fork brace is a big improvement.  I noticed the difference on the first 90 degree corner I rolled through.  The bike seemed to turn into the corner easier and follow the line better.  And this was at about 15 mph from one city street to another. 

The LMIII and Monza forks are very similar and I blogged rebuilding the Monza forks on WG.  You may find it helpful: http://wildguzzi.com/forum/index.php?topic=75441.0

Hint: it's much faster to refill the fork legs with 70cc fork oil if you use a syringe and inject it from the bottom rather than dribbling it down between the damper and the inside of the fork leg.

SED
Thanks for the insight and links; very helpful!! I'm sending the lowers out for powder coating this week and will start getting the parts ordered up. Appreciate the assistance.

[Antietam Classic Cycle]

Thanks for the information; beautiful bike!

Customer's bike. Resides in Dayton, VA.