35 mm fork options

[Petrus Rocks]

I have a stripped down Cal II.  I know I can get new FAC or Wirth cartridge dampers and a fork brace to upgrade them. 
What other right side up conversions have been done?  I'm after increased rigidity and adjustability.
Any suggestions?

[redrider90]

I have a stripped down Cal II.  I know I can get new FAC or Wirth cartridge dampers and a fork brace to upgrade them. 
What other right side up conversions have been done?  I'm after increased rigidity and adjustability.
Any suggestions?

Wirth cartridge dampers? I haven't seen them. Is this a typo and you meant Wirth progressive springs?

[steven c]

 If you can find it you could bolt on an EV front end.

[Petrus Rocks]

Thanks for the responses.  Sorry, Wirth springs- I'll look into an EV front end.  I'm willing to go for a larger fork but the devil is in the details.

[Antietam Classic Cycle]

With th stock 35 mm tubes, I'm not sure how much you can do for rigidity other than a fork brace, but IIRC there was a thread a while back about putting Honda CBR? guts in the Guzzi fork. That would give you adjustability.

[Petrus Rocks]

Thanks Charlie, I'll research that.  that's the kind of thing I'm looking for.

[mtiberio]

back in the day I had heard of folks installing the damper rod internals from a ceriani (or maybe it was marcocchi) 35mm fork into a guzzi 35mm fork. damper rods forks are far from perfect, but have some advantages over the screen door closer cartridges was have as options.

[charlie b]

I have the FAC's and Wirth progressives.  Not very impressive and not adjustable.

[kevdog3019]

back in the day I had heard of folks installing the damper rod internals from a ceriani (or maybe it was marcocchi) 35mm fork into a guzzi 35mm fork. damper rods forks are far from perfect, but have some advantages over the screen door closer cartridges was have as options.

Yes, Cagiva Allazurra bikes had 35mm Marzzochis on them and they are damper rod type but rock solid. Milich put them on my Guzzi hot rod and it's love. They are stiff at speed but no flex. eBay or Milich is your friend.
K

[harrytief]

I've had realy good results replacing the 35mm guzzi fork with USD gsxr forks on both my cx100's. Better rock solid stability and agility at all speeds for me with world class brakes for free. just saying.
Harry

[racasey]

The Aluzzura fork looks like a good option for a V65 special I'm building.  I ordered a used set with yokes and steering stem on-line, after being told they needed new oil, and perhaps set the preload. 

Upon cleaning them up in preparation for new seals and oil, this is what I found. 

https://m.youtube.com/watch?v=5wwfDthaMhQ

The left tube is similar, at 0.014" runout.  The seller says they are 99.9% good, and safe to use.  Your thoughts?

Ciao,
Dick

[bmc5733946]

Those are bent, would not use.  Maybe??? could be straightened in a press if not, Forking by Frank for tubes!

Brian

[steven c]

I've had realy good results replacing the 35mm guzzi fork with USD gsxr forks on both my cx100's. Better rock solid stability and agility at all speeds for me with world class brakes for free. just saying.
Harry

How difficult is the swap? That would be a neat mod for my Cal 2.

[harrytief]

Fiddly but not difficult.  Amazing how 2016 competent these old tonti framed bikes can be. If you can get past the "philistine " notion of altering a "classic", then it almost seems that Mr. Tonti  was a visionary. He designed a motorcycle that can be  a blank canvas for its owner for a lifetime and beyond. Search on this site for my brief how to.

[Petrus Rocks]

Racasy, Ditto. Forking by Franks will do it, so will this place-http://www.motocd.com.  I've done it with a couple of V-blocks and a press.
The Marzocchi forks will work.  I have added cartridge emulators on a Betor fork conversion for my Triumph. 
Worked very well, adjustable. 
Harrytief, it's a thought but a lot more work.  I'll take a look at your thread, thanks.
With your conversion you needed new rotors as well, correct?  Probably need a new wheel too.  I have Borranis on it now.

[harrytief]

I used brembo 6 hole 5mm offset 320mm rotors found on all new guzzi and some ducati. I did so because I wanted to take the most advantage of the radial calipers that came with the USD showa forks I used. The fork conversion will determine which rotors you use. I am preparing a '93 gsxr front end using brembo axial 65mm calipers on adaptors to use in my eldo build if I am unhappy with the stock disc brake fork. I can use a variety of rotors using diferent adaptors. The adaptors l chose came from ebay and allow the same 320mm rotors.
For wheels, I used borranis on one cx100 and the OEM cast wheels on the second. The trick is to matched bearings and spacers to the wheel and axle you use. All doable.
good luck
Harry

[Petrus Rocks]

Thanks Harry.  Glad to hear you were able to use the Borrani's.  So the triple clamp geometry works well?  I may look for older right side up GSXR forks if the triples work well.

[dan_s]

Simplest things are bitubo or fac dampers and a fork brace. My bike turns very nicely with them. You could adapt marzocchi dampers but the former are a straight fit, in stock usually and probably as good. I'd replace to progressive springs only if the first upgrade will no satisfy. Should these not do, fit a guzzi 40mm fork or a marzocchi m1r or your other favourite front fork.

[harrytief]

Note that when fitting any non oem triple clamps that you may lose the function of the original steering stops. Plan ahead or you will return from your first ride embarrassed by the new dents in the front of your gas tank. Why do I know this...
Harry

[redrider90]

Interesting comment on not upgrading to progressive springs unless adding bitubos or FACs + fork brace doesn't do enough. I'd take the progressive springs before I tried the fork brace.
OP said he was interesting in rigidity. Cal II would probably be the same as my Mille front end as far as performance albeit the Cal II is slight shorter spring.  At 15K miles on the 90 Mille my front end drop 2" just from rolling off the throttle. Imagine what it was like in the twisties!   The original springs in the 35 mm fork units were garbage. If you want stability then Wirth progressives will give it but without adjustability. If the fork unit is already apart then it would be a huge waste of time to add FAC or bitubos and fork brace and not go with the springs. I did bitubos and springs and never put a brace on my Mille. Now I do not ride as hard as many folks, but just those 2 units gave me all I needed.

BTW I also replaced my tubes with Forks by Frank. They had them in stock a few years ago.

[jetmechmarty]

I upgraded the the 35 mm damper rod forks on my old Yamaha.  It transformed the ride and I'm thrilled.  I added custom wound straight rate springs, Race Tech emulators, and a fork brace.  Parts were acquired from Traxxion Dynamics.  For better results, just send them the forks and write the check.  www.traxxion.com  The emulators are tuneable.

It's much better than it was when it was new!

[dan_s]

I found the original front fork spring good enough. Some not very heavy people wrote about bottoming out of the fork with progressive springs.

[Petrus Rocks]

I installed emulators on my Triumph with Betor forks.  They were a fantastic upgrade.  Problem is, you can't do that with Guzzi forks.  For me. the guzzi front end is both mushy and harsh.  If I knew ID measurements on other forks I would be willing to install cartridges or even damper rods with emulators.  I want to keep the Wire wheel Borranis and I like the look of right side up forks on this bike.
Having heard mixed reviews about the damper and spring upgrade I was hoping for some lower cost alternatives to a new set of forks, rotors, etc.  The Guzzi is one of five bikes commanding my attention and $$.  I'm always looking to engineer something as opposed to
spending a lot. 
I'm glad to hear all ideas as I may keep the bike long term and reaaly upgrade the suspension.

[Antietam Classic Cycle]

I know of a few Guzzis wearing Yamaha XS650 and Suzuki GT750 forks. Not sure if they'd really be any better as far as rigidity or adjustability, even with modifications, though.

[charlie b]

I found the original front fork spring good enough. Some not very heavy people wrote about bottoming out of the fork with progressive springs.

I have done that quite a few times with mine (progressives).  I am not light, at 200lb.

[wymple]

I upgraded the the 35 mm damper rod forks on my old Yamaha.  It transformed the ride and I'm thrilled.  I added custom wound straight rate springs, Race Tech emulators, and a fork brace.  Parts were acquired from Traxxion Dynamics.  For better results, just send them the forks and write the check.  www.traxxion.com  The emulators are tuneable.

It's much better than it was when it was new!



Get that SS El Camino out of the pile and give it some love....

[jetmechmarty]

I stopped using the El Camino as a trash bin and got the old girl running.

Why won't the Guzzi forks take emulators?  It might respond well to new springs and fresh fluid.  I'm not a fan of progressive springs, at least, not on a motorcycle.  I like a proper rate spring.

XS650 forks are simple and cheap.  1977 and later are 35 mm.  Earlier ones are 34 mm.  Brackets are available to mount Brembo calipers on them.

[redrider90]

I have done that quite a few times with mine (progressives).  I am not light, at 200lb.

agreed. I'm 6'5" @200# and find even when 2 up and + fully loaded for a trip + wife = 1000# total weight,  the progressive springs are more than adequate on the Mille. 

[Petrus Rocks]

Guzzi forks have sealed cartridge dampers, no way to install emulators.  If I get another set of 35 mm forks I would get some that the Brembos already fit.  I may bore out my triple clamps and get 38 mm marzocchis or...and emulators.
I'm on Britbike for my Triumph. 
There's a Scottish member that is modifying CBR600 cartridges to fit various Triumph/BSA forks. 
That's the kind of thing I was hoping to do. 
The Progressive springs are a good idea.

[jetmechmarty]

Guzzi forks have sealed cartridge dampers, no way to install emulators.  The Progressive springs are a good idea.

Hmmmm....  If the Guzzi forks have cartridges, that means they have valving in them, correct?  Can you adjust them?  If so, progressive wound springs will screw that up.  Progressive springs are a one size fits all improvement for old fashioned damper rod forks.  I respect the opinion of those who disagree, but I'm no fan of progressive springs.  If you mix them with tuneable forks, you'll never be able to get them right.