'07 Norge 2V fork spring upgrade

[brider]

Did some searching and the "fixes" for the undersprung Norge forks is kinda all over the place and a lot of links are dead (I'm coming in late to the game...).

Does anyone know what the KG/mm or lb/in rating is for the stock fork? Length, also? I have a good link to a Sonic Springs website, but I'd really like to know what the stock specs are before I dig deeper. I figure new springs & new/heavier oil is the place to start.

[Huzo]

Hmmm…
I must have gotten different springs in my ‘07 Norge from new. It’s done 215,000 k and they seem fine…

[brider]

I suspect too-soft springs because of the endless posts attesting to this PLUS the front end dives alarmingly with too much front brake, and I'm thinking I don't want to address that completely with compression damping (heavier oil). Shop manual says fork oil is SAE 5W-SAE 20W, which doesn't tell me squat about the FACTORY weight, so I'm kinda annoyed there, and I wish I could find a spec for factory spring rate, but I know this has been researched before for the Norge so I'll just keep looking.

[Huzo]

Really though Brider, if you squeeze the lever with finesse, it all just seems good. Also, does it really matter ?
It’s just part of the bike going about it’s business.
I like the way it responds to the rider inputs, some guys go to a lot of effort to try to alienate themselves from what the bike is telling them.
I reckon it feels “alive” when it alters attitude.

[Huzo]

Guzzi Ride has had a set of 1200 Sport forks up for grabs here for ages…
Also.
Increasing compression damping, won’t reduce the AMOUNT of dive that you get, just the RATE at which that limit is reached.

[Tony F]

Are the forks bottoming out as it is currently set up?

[brider]

Thanks for the Guzziride 1200 fork lead, but it's (1) leg, not 2. If it was 2 I'd be interested.

The forks aren't bottoming, and I wouldn't really have a complaint EXCEPT for the excessive diving under fast, hard braking. If I touch the front brake when leaving my driveway because a car came over the hill I didn't see until the last second, the front will collapse spectacularly. Hat's off to Huzo for the opinion that a good technique can mitigate that characteristic, can't argue with that, but I personally don't like it. I ride the same routes/conditions/technique with my pig-of-a-Cal 2 (well, USED to ride until the ATF system re-re-re-failed...) and it has upgraded springs & dampers and when I hit the front brake hard it does not dive.

[Don G]

I had the same problem that you describe, heavy braking was dangerous, if I remember correctly I sourced some fork internals from Guzzi-tech, also changed the weight of oil and the dive was corrected.  DonG

[blackcat]

The early numbered Norge's had this front end problem, I forgot which kit I put in mine but it made a big difference. The problem I was having was tail wagging in turns but that was solved and I also changed the rear shock. Both were worth the money and I purchased the products from Guzzitech. I'm sure there are other options out there that don't need to be sourced from Guzzitech.

[guzzisteve]

When it comes to parts you pay who has the fix regardless of your issues with seller. I know riders bought from Italy

ON SALE right now for $279, reasonable amount to fix issue in front end.

[brider]

ON SALE right now for $279, reasonable amount to fix issue in front end.

Who/what/where is this sale?

I didn't mention that my '07 has a shock upgrade, not sure if it's just a spring or entire unit, it came that way when I bought it, PO said "the shock has the upgrade", I know nothing more than that (wish I knew how to visually identify the "upgrade") but the rear has never been a prob.

[guzzisteve]

https://gtmotocycles.com/products/norgebreva-fork-kit

[brider]

Thanks for the link, I registered @ guzzitech but don't have privileges yet to ask questions. Besides the springs, is the rest of the kit easy to install by someone who knows how to use a wrench?

[guzzisteve]

You don't have to belong to forum to buy from store. Lot's of info on forum for install of fork parts plus it comes w/instructions. Not too difficult.

[guzzisteve]

All I did was a search, you'd be surprised-------------------------------------

https://www.carpimoto.it/en-US/Bike_Moto-Guzzi_Norge-1200/Specific/44288_FM100KE-Matris-Fork-Springs-Plus-Preload-Kit-for-Moto-Guzzi-Norge-1200-07-09.htm

https://www.bellissimoto.com/parts/suspension/rear-suspension/rear-shocks/matris-m46kd-monoshock-for-the-moto-guzzi-norge-1200-2007-2009-and-1200-8v-2010-2016-1

I have dealt with Bellissimoto before with good results, call & they could order you something------------------

All in a search

[kingoffleece]

I thought mine were just fine until Hamlin Cycles offered to put a pair of their reworked forks on my bike.  HUGEEEEEEEEEEEEEEE difference.  I thought the rear was OK stock too until it was up on the lift and I could see half of the kickstand worn down.  Did the rear end of the bike too and it was and F! car with a Cadillac ride.

You can send the forks there for service if you go that way.  And you don't need to be running MotoGP speeds to get the improvement.  Until you've ridden a bike properly set up for you you'll never experience just how fantastic it can be.

[SemperVee]

  I have the Matris fork spring kit in my Hi-Ho Silver 07 Norge and it makes a HUGE difference.  I did not install them, the prior owner did but my previous RED 07 Norge had stock and was shite, too soft.

[brider]

My rear shock has been "done", and I like the idea of the Matris fork kit but I really want to research just what my current fork spring rate/length is and see if I can find some springs and do a fluid upgrade. Might swing by Hamlin to see if I can talk to them about it.

[kingoffleece]

heck, you're already there with the forks off-go big or go home.

[BRG-BIRD]

I installed the Matris system myself and was very pleased with the result

[faffi]

A free way to firmer fork springs is to shorten them. I have done this on several bikes, last on my Virago-based build. If you cut a straight rate spring into two halves, each part will have a rate double that of the original spring. You will need to fit a suitable spacer to compensate for the reduction in spring length, but usually you will want less preload now that the springs are firmer. A good thumb of rule is that you want a spring that will give you the correct sag with no more than 1 inch of preload, which again means that the top of the spring - unladen, wheel off the ground - should sit about even with the top of the fork stanchion top, and no more than 1/2 inch above.

These pictures are from my Deauville 650, where I shortened the springs by 25%, but effectively gained more in spring rate since I cut off the soft part of the springs.

The cut, the long part to be retained have already been heated and shaped flat-ish


Here you see one raw cut end, and one that has been heated to glowing red and bent flat-ish, then ground until perfectly flat

[Huzo]

….now that the springs are softer.

This was the bit I didn’t get…

[faffi]

This was the bit I didn’t get…

Thank you for pointing that out, corrected now in my post above - I forgot to change that when altering the sentence during my edit.

[brider]

If you cut a straight rate spring into two halves, each part will have a rate double that of the original spring.

??? Springs are rated in force/unit length (of compression), like lbs/in. Nowhere in that equation does free length come into play, so HOW does a spring cut in two get stiffer than the original rating?

[faffi]

In laymen terms, I would say it is because you have only half the number of coils that can compress. The load placed on the whole spring is the same as for every coil, meaning that the more coils you have in a spring, the softer it become, since each coil will compress the same amount. No, it isn't totally logic to me, either, but real life experience have confirmed the theory. A good example is a valve spring. Very short, not unlike a fork spring in wire dimensions, but very stiff.

[Huzo]

??? Springs are rated in force/unit length (of compression), like lbs/in. Nowhere in that equation does free length come into play, so HOW does a spring cut in two get stiffer than the original rating?

That makes sense to me.
If a coil has 100 turns, is loaded to 50 kg and compresses 100 mm, then each turn deflects through 1mm.
 But if it has 50 turns, is loaded to 50 kg, it would only compress 50 mm.
This means that you’d have to load it twice as much (100 kg), to compress it 100 mm.
He’s actually right.

[brider]

I was juuuuust about to call BS on this cut-the-spring-to-make-it-stiffer theory because I couldn't reconcile it with the classic F=kx equation, but the custom auto biz shows it to be true:

https://www.eatondetroitspring.com/cutting-coil-springs-calculations/#:~:text=The%20only%20thing%20that%20will%20change%20will%20be,when%20cutting%20the%20coil%2C%20the%20spring%20rate%20increases.

What isn't mentioned, and one of my concerns: Coil bind in the shortened spring. What determines fork stroke in our Guzzi forks, and how do you determine if the shortened spring won't bind up before full stroke?

[Huzo]

It’s true because, when you halve the length but attempt to compress the same distance, you are deflecting each coil twice as much.

[faffi]

What isn't mentioned, and one of my concerns: Coil bind in the shortened spring. What determines fork stroke in our Guzzi forks, and how do you determine if the shortened spring won't bind up before full stroke?

Fork travel is determined by the damper. Typical wheel/fork travel is in the 5-6 inch range. So as long as you have more clearance/space between the spring coils than your wheel travel, the springs will not bind. There was plenty of spare travel on the springs in my Deauville compared to the limits imposed by the damper.

[PJPR01]

My rear shock has been "done", and I like the idea of the Matris fork kit but I really want to research just what my current fork spring rate/length is and see if I can find some springs and do a fluid upgrade. Might swing by Hamlin to see if I can talk to them about it.

Many years ago I upgraded my front springs/heavier oil to Hyperpro springs.  MPH did the install, every 5 years or so I refresh the oil.  That combined with a Wilbers rear shock completely transformed the bike for 2 up and sportier riding.  $'s well worth investing as the stock setup is far too spongy.