Forks Revalve respring

[al_roethlisberger]

Yep, only time will tell on the spring rate selected.... I told LE that I too was a sport-touring and not very aggressive kinda guy.... so who knows

 

It's not a big deal though. I've only currently got $120 invested in their first go-round, so I can always have them tinkered with again if they are too stiff, etc.

 

I only had the springs replaced, no valving changes...

 

al

[Guest captain nemo]

Lex,

 

I liked your website file on suspension. Very good. I guess I must have a very soft spring because I have the preload distance measured at 150mm, yet I have nearly two inches of sag! Maybe I went overboard because I hated the drive home from purchase where I nearly broke my ass and teeth on the interstate. Acording to the experts this puts me in the very plushed-out touring category. I'm sitll watching and observing. What are the 'symptoms' of running corners where sag is too long? I want to know what they are so I can be alert to it. So far, I have not noticed any funny feelings of any kinds in corners or high speed car passing (105 mph.).

[Lex]

Captain,

 

As it says on the site, Moto Guzzi specifies that if the spring is less than 152 MM with the sag set the spring is too soft. If you are at 150 MM and still have two inches of sag you deffinatly need a stiffer spring. I don't have the Moto Guzzi specific knowledge to suggest a good replacement, I'm sure a good suspension shop could help with that. If you go that route I'd love to hear what they suggest and get your feedback on the results. The web site is just an embrio at this point (and will stay that way for a while as my life is about to get very busy) but one of the things I would like to add is some suggestions for set up like what vkerrigan provided with his fork changes.

 

You have already experienced the most common symptom of too soft springs/ too much sag, the shock will bottom and "break you ass and teeth". Imagine how much fun I had the first time I took my brand new, stock Guzzi on one of my favorite tight, very bumpy roads, I spent more time with my ass in the air than on the seat. The more subtle signs are poor feel and traction from the front end as the low rear end "rakes" the front and shifts the weight to the rear. The later is a real problem as our bikes already carry too much of their weight on the rear of the bike.

 

I told LE that I too was a sport-touring and not very aggressive kinda guy.... so who knows

 

Al, OTOH, maybe LE just had a set of 1.05 springs laying around and it was too much trouble to order stiffer springs for my bike.

 

Cheers,

 

Lex

[Guest vkerrigan]

WildJackal & Lex,

 

Lex is right on with the suspension for the 02 LeMans....Marzocchi forks and Sachs shock. The only downside to the work on the forks is that it has now highlighted my shock deficiencies (undersprung...compensated by high preload and compression damping). At some point this winter, I'd like to do as Lex and have the shock re-valved and re-sprung as well. I know from previous posts here the Ohlins & Pensky shocks are in the $800-$1,000 range. I'd be interested to know what LE charges for the mods to the Sachs.

 

Happy Trails.......VK

[Guest captain nemo]

Lex,

 

According to my V11 manual, the completely released length of the rear spring is 165mm. The preload can be varied from 8 to 14 mm. This means that a measured length on the bike from 157mm to 151mm is acceptable as long as the sag is correct. I have mine set at the 'stiffest' setting - 150, and yet, as you say, my sag is too long. However, just what the sag should be is probably a matter of debate for any given rider. I don't know from my own experience what is best. Right now it seems to me that my 'soft' spring is absorbing bumps much better than a 'stiff' spring and I like it that way. I am sure that I am not experiencing 'bottoming out.' The harsh ride that I experienced from the PO was a spring length of 145mm. That delivered shock straight to my ass. I am also of the opinion that the soft spring lowers the rear end and, thus, the center of gravity. I am not sure if this 'rakes out' the front end. It could I guess. But maybe a lower overall height has other advantages.

 

It is also possible that the extreme harshness and stiffness of a road racing bike is to compensate for very hard braking preceding corners. This is just not the Guzzi's realm, so I wonder if we are comparing apples to oranges when mags speak of correct sag. Correct for whom and where? A Guzzi would not be my choice of race bike; it would be my choice for smooth cafe bike where turning technique emphasizes smoothness and grace - not sudden and abrupt changes in forces for which stiff shocks are a must.

[Baldini]

What are the 'symptoms' of running corners where sag is too long?

 

You'll know it if there's a problem...Bouncy, wallowing back end brings weaving, vague, light front end & understeer...Bike stands up & heads for the ditch on mid corner bumps.. .you can tell if it's bottoming out the shock - just by marking the damper rod with grease & checking travel after a ride.

 

We all ride different & if you're happy as it is - why worry?

 

KB, Wales

[Guest chong-chong]

Check out this article on Race Tech's website regarding setting up proper spring sag. I think it's very helpful:

http://www.racetech.com/articles/Suspensio...nAndSprings.htm

[Mike Stewart]

WildJackal & Lex,

 

Lex is right on with the suspension for the 02 LeMans....Marzocchi forks and Sachs shock. The only downside to the work on the forks is that it has now highlighted my shock deficiencies (undersprung...compensated by high preload and compression damping). At some point this winter, I'd like to do as Lex and have the shock re-valved and re-sprung as well. I know from previous posts here the Ohlins & Pensky shocks are in the $800-$1,000 range. I'd be interested to know what LE charges for the mods to the Sachs.

 

Happy Trails.......VK

 

I had my Sach rear shock revalved and resprung by LE earlier this year. The cost was about $380. dollars. This included the spring, the new shock head (which was needed to install a new shaft seal) and revalving. I was not compleatly happy with the revalve job and I am going to send it back to have the high speed dampening relaxed some. The ride is ok if riding two up or have the bike fully loaded with camping stuff. But riding solo with the correct spring sag, the bike just does not feel compliant and the rear end will send you sailing over the bars when an abrupt bump is hit. I thought I had this problem figured out last week untill I hit a good abrupt bump and my butt and feet were airborn for a few seconds. Man, what would of happened if I was going around a high speed sweeper? Anyway I might have the LE shock up for sale after I have it revalved again. Any takers

[Guest WildJackal]

I sent Aftershocks the following:

 

I have a 2003 Moto Guzzi Sport with Marzocchi USD fork and Sachs Boge mono shock. I would like to buy the correct springs for my weight - 225 lbs.

 

Can you tell me what you recommend and how they differ from stock?

 

Phil Douglas replied:

 

You will need to go 15% stiffer front and rear than stock. That is what it works out to be for your weight. I would have to size the rear spring to give you an exact rate but the forks will take .90kg/mm.

 

Thanks Phil!

[Mike Stewart]

I sent Aftershocks the following:

 

I have a 2003 Moto Guzzi Sport with Marzocchi USD fork and Sachs Boge mono shock. I would like to buy the correct springs for my weight - 225 lbs.

 

Can you tell me what you recommend and how they differ from stock?

 

Phil Douglas replied:

 

You will need to go 15% stiffer front and rear than stock. That is what it works out to be for your weight. I would have to size the rear spring to give you an exact rate but the forks will take .90kg/mm.

 

Thanks Phil!

humm,

 

LE came up with 1.05kg. on my V11Sport and I weigh in at 200 lbs. This was the same weight springs Al got when he resprung his Ohlins and he is at 200 lbs also.

 

Mike

[Baldini]

Mike,

 

I'm 210lb (Imperial) w/gear. I run 10Kg front/100Kg rear in Ohlins. They're fine, 1.05/105 would be fine too I suspect...maybe even a little better? Depends on how you ride it I guess.

 

Am I right in thinking that a spring should require some preload for correct sag & that if a spring was used that required no preload to get sag, it would neccesarily be too hard? If so, is their a rough percentage of a spring's unloaded length that should be regarded as optimum for preload?

 

KB, Wales

[docc]

If the spring has no preload it will be fully extended. This will not allow the suspension to extend to follow road imperfections. It is critical the suspension have some 'reach' to maintain traction.

[Baldini]

...And in an ideal world what should that 'reach' be or does it depend entirely on how the bike is to be used?

 

(Still no sign of them posts Docc... !)

 

Cheers, KB,Wales

[docc]

Good point, I agree. For instance, the corner I crashed in went slightly off-camber in the middle of the lane where I lost traction. Heeled over, my suspension needed to 'reach' out over the camber break to press the tire for more available traction.

 

The high preload, high damping, hard tires and high pressures all conspired with a noncompliant suspension to admit me to the Tarmac Rub-Club.

 

Now, I won't say I'm a really hot rider. But at that split instant I needed everything the bike could give .

[Kiwi Dave]

If the spring has no preload it will be fully extended. This will not allow the suspension to extend to follow road imperfections. It is critical the suspension have some 'reach' to maintain traction.

 

All suspension systems (IMHO) have some preload, even at their minimum setting. Otherwise the springs would rattle.