• Ciao Guest - You’ve landed at the ultimate Guzzi site. NEW FORUM REGISTRATIONS REQUIRE EMAIL ACTIVATION - CHECK YOUR SPAM FOLDER - Use the CONTACT above if you need help. New to the forum? For all new members, we require ONE post in the Introductions section at the bottom, in order to post in most of the other sections. ALWAYS TRY A SEARCH BEFORE STARTING A NEW TOPIC - Most questions you may have, have likely been already answered. DON'T BE A DRIVE-BY POSTER: As a common courtesy, check back in and reply within 24 hours, or your post will be deleted. Note there's decades of heavily experienced Guzzi professionals on this site, all whom happily give endless amounts of their VALUABLE time for free; BE COURTEOUS AND RESPECTFUL!
  • There is ZERO tolerance on personal attacks and ANY HYPERLINKS to PRODUCT(S) or other competing website(s), including personal pages, social media or other Forums. This ALSO INCLUDES ECU DIAGnostic software, questions and mapping. We work very hard to offer commercially supported products and to keep info relevant here. First offense is a note, second is a warning, third time will get you banned from the site. We don't have the time to chase repeat (and ignorant) offenders. This is NOT a social media platform; It's an ad-free, privately funded website, in small help with user donations. Be sure to see the GTM STORE link above; ALL product purchases help support the site, or you can upgrade your Forum profile or DONATE via the link above.
  • Be sure to see the GTM STORE link also above for our 700+ product inventory, including OEM parts and many of our 100% Made-in-SoCal-USA GTM products and engine kits. In SoCal? Click the SERVICE tab above for the best in service, tires, tuning and installation of our products or custom work, and don't miss our GT MotoCycles® (not) art on the BUILDS tab above. WE'RE HERE ONLINE ONLY - NO PHONE CALLS MADE OR RECEIVED - DO NOT EMAIL AND ASK QUESTIONS OR ASK TO CALL YOU.
  • Like the new V100, GuzziTech is full throttle into the future! We're now running on an all-new server and we've updated our Forum software. The visual differences are obvious, but hopefully you'll notice the super-fast speed. If you notice any glitches or have any issues, please post on the Site Support section at the bottom. If you haven't yet, please upgrade your account which is covered in the Site Support section or via the DONATE tab above, which gives you full site access including the DOWNLOADS section. We really appreciate every $ and your support to keep this site ad-free. Create an account, sign in, upgrade your account, and enjoy. See you on the road in 2024.

74 850t front suspenders

Mc Tool

Mc Tool

Cruisin' Guzzisti
Joined
Jan 23, 2011
Messages
104
Location
Thornbury , Riverton, New Zealand
When I put my 850t together I got the cheapest insert things I could . Got a lot of pot holes in my drive and these forks produce quite a loud clank and Im not sure what to blame ...... anyhow The forks are shite , so time for an upgrade . Im going for progressive springs but I sure would like a heads up on the inserts , and any hot tips you may have . Thanks
Hamish
 
It has been a long time since I worked on a T or T3. I researched progressive springs for one in the 1980, but at that time, none were available. As for the damper, cheap never works. The factory one wasn't any better that one for a screen door. My recommendation would be to find a shop that specializes in suspension. Two springs might be fitted (a soft and stiff) in each leg to help the softness of the original springs. This would need to have some type of keeper made to keep the springs in line in the assembly. As for the dampers, you get what you pay for. Hopefully someone will chime in that has accomplished this recently. As you are working on front suspension, a Teleflex or similar fork brace will help with handling quality. Those 35mm tubes are a little flexible.
 
Have you contacted the owner of this forum GT-Rx Todd?? I would be surprised if he did not have a source.

Some years back I bought forks, springs & dampners from MG Cycle Supply (mgcycle.com)

There are different length forks used on the T's. Early ones were shorter, later ones were longer. The forks. springs & dampners have to match. I always used the shorter set up just because I liked the way the bike handles when it was set low to the ground, never had a scrape problem but I don't live in the twisty mountains either.
 
You could use this "combo" that MG Cycle sells:

Wirth progressive springs:
mgcycle.com/product_info.php?products_id=1142
and FAC dampers:
mgcycle.com/product_info.php?products_id=2165

Not inexpensive, but good quality. Once they "break-in", fork action is much better than stock.

I've also heard of guys installing dampers from a Honda CBR600? or something like that into the 35mm forks.
 
Late to the party again.

I put Wirth progressive springs from MG Cycle in my T some years ago. Made huge difference. Front fork used to bottom out frequently when I hit the brake hard. Not anymore, bike handles better. I was too cheap to put FAC dampers in (there was no quotable delivery at the time either), so went stock. Didn't take long for those to stop doing much in the way of damping.

On my SP1000 a couple years ago, I put Bitubos w/ Wirth springsand new IKONs on the back. Like new bike! (well, OK , newER). Highly recommended. There's no off shelf Bitubo model for 850T, but I think I might get just make custom spacer rods to connect to damper rod bottom end of sliders.Shouldn't be that hard. Or maybe go with FACs if there's an off shelf option.

BG
 
The dampers in the forks are rebuildable and it makes a big difference. I did mine recently.

There was a thread on this forum which gave the seal part numbers but I can't find it. Take your old seal to a bearing specialist and they should be able to match them. You need four.

Good luck.
Dave
 
Maybe for the sake of any people new to the details of guzzi front suspension, we should mention that FACs, and Bitubos are aftermarket dampers and are rebuildable (at a corresponding price premium). The units that came stock on most old guzzis are pressed and swedged together and are slightly higher in quality than the damper on your screen door. They either can't be rebuilt or aren't worth the effort to start with.

In Guzziology, Richardson spends some time on this topic, and totally predicted my experience with stock damper replacements. He actually used the word "wretched" to describe the 850T stock front end. They "break in" (lose most of their damping capacity) after roughly 5000 miles. I put new stockers in my SP that winter before the last national rally in Salida,CO. Roughly 1000 mi there and 1000 back, with about 50mi of dirt mountain roads and washboard in between. After the washboard, the valving, which had been clearly evident before, with an easy compression, and a slower rebound, was toast. I suspect there are some plastic parts in there that can't stand up to much heat. FAC and Bitubo must have this figured out better.

Having said all that, I have to say my 850T is still a gas to ride. Seems to have more pep that the SP. Cams? Less weight? don't know, but when the throttle is twisted it goes, as dad used to say, like a scalded dog.

The Bitubos in my SP are still doing the job, maybe almost too stiff, but they show no sign of giving out after over 15,000 mi
BG
 
Hi all

If I may, I'd like to glom onto this old thread and ask a question. I have a shop, that though it occasionally dabbles in Guzzis (I used to have an Eldo myself) I am really pretty much a full time suspension shop. In any event, a customer has dumped a box of parts in my lap to pieces together and old 74 or 75ish 850T, including some springs and FAC carts. I suspect there parts are a bit mismatched, because my distant memory doesn't recall any trouble getting the spring seated between the cartridge tube and the spring seat. On this one, it seems to require a ridiculous amount of spring preload. It would end up putting a LOT of load on the little circlip. It's been ages, but I thought these had very little preload with the spring just on the cart assy.

Does anyone have any spring or cart dimensions?

I seem to remember them being around 430mm, and these are a bit north of 445mm

Could my theory that these springs are over-long be correct?

The length of the cartridge damper rod from bottom of cart to the circlip groove is 428

Thanks for any guidance.
Roger
 
From MG Cycle's website:

Original type short fork damper cartridge for V35, V50, V50 II, V7 Sport, 750S, S3, LeMans 850, 850T, 1975-1978 850T3, and disc brake equipped Eldorado. 395mm overall length.

Fork spring as original for disk brake Eldorado, V7 Sport, 750S, S3, 850T, 850 LeMans, 1975 to 1978 850T3, 1975 and 1976 Convert. These are 420mm "short" springs that match the early shorter damper cartridges on these models.
 
Charlie is on it!! From the 750/850 workshop manual -- spring length is 421 +or- 2.5mm.
Dampner rod is threaded w/locknut to rod w/holes goes to bottom pocket for spring.
You can adjust it on the threaded rod a bit for total length.
 
Hi all

Thanks for the replies guys. All helpful. I'm still not dead sure that these 446 spring are right to cram into the 428ish space I have (though 18mm of installed preload is not ridiculous. I'd still like to confirm I'm setting this up right. How much do you guys usually have to compress the spring to put on the seat and circlip?

And to the GTM administrator reply, I'll definitely use you guys to source carts with on the next one. These just came to me this way and I'm working with what was given to me.

Thanks
Roger
 
thisoldtractor.com/moto_guzzi_tonti_fork_spring_and_damper_information.html

You can download service manuals from that site as well. In there you can find drawings of the fork internals
 
Last edited:
You must log in or register to reply here.
Back
Top