2000 V11 Sport Fork Height

[Guest Mich-Guzzi]

I have a V11 Sport with the Marz forks. I removed the forks and shock to change the springs to a more appropriate rate for me. When I reinstalled the forks, I set the fork tubes flush with the top triple clamp. Later, I also added the MPH bar risers and Napoleon bar end mirrors.

 

Now the bike has more of the speed wobble than before (it's always had a bit - that's one of the reasons I went to higher rate springs). And the steering seems light at freeway speeds. It seemed to get worse after the MPH and bar end mirrors were added.

 

Can anybody tell me the stock fork height setting? Also, I see that most people drop the forks from stock. What's the consensus and how is it measured? From the top of the fork tube? Or the top of the cap?

 

And has anybody had wobble problems with changing to bar end mirrors?

 

Thanks in advance.

[Guest ratchethack]

Mitch, I've been down this road apiece - setting it up, that is. I've NEVER had a trace of a speed wobble or headshake. There is NO reason for this bike to have either if it's correctly set up.

 

Coupla things:

 

You didn't indicate your riding weight, the new spring rates, or your laden and unladen sag settings front and rear. All of this is critical. Have you correctly set the air gap in the forks? Once I up-rated my fork springs by 50%, I experimented for awhile with many different fork heights and found I was able to raise the tubes by 8-10mm, which gave me a good "neutral" trade-off point. It's measured from the top of the tubes to the top of the upper triple clamp.

 

The fact that you put bar risers on gives me some concern about rearward weight bias, which would fit what you say about the front end feeling light. The V-11 has an inherent problem in this area, and when you raise the bars from the stock position, it makes the problem considerably worse. If you've correctly rated your fork springs, you can raise the fork tubes, and this will give a surprising amount of help in decreasing the rearward weight bias. May I also suggest flexing your arms to get way up forward over the tank and front wheel, particularly in the twisties. This should help a tremendous amount by getting you closer to a neutral handling balance front and rear.

 

May I recommend this link for just about all you should ever need to know to get the suspension dialed in:

 

http://www.strappe.com/suspension.html

[Guest Mich-Guzzi]

Here's the answers I have:

 

Rider weight: 280 lb.

 

Spring rate: I don't know exactly but they were installed by the local dealer's tech - who is an authorized Ohlins service guy. They are very good Guzzi dealer. He also changed the fork oil and set the oil level. I think the fork springs are the highest rate springs he could find that would fit. And the shock spring is a 6.0 I believe. He has also done my track bike (not a Guzzi, an SV650) which worked out great.

 

Sag numbers: I have not checked recently - but they are in the ballpark. And there is a lot less sag now since the spring upgrades. I'll check when I get a chance.

 

Riding the bike tells me the rates are pretty good. The ride is firm without being choppy. The stock springs let the front end mush over anything and the bike defintely rode lower in the stroke of the fork. And while I'm far from being an expert, I have a fair amount of experience with other bikes.

 

I have also changed to the 160 rear tire - currently the bike has Mich. Pilot Sports - which dropped the rear end a bit.

 

I agree with the rear weight bias theory. That's what led me to the dropping the forks plan. I will probably set them at 10mm above to start. But is the stock setting flush with the triple?

 

Keith

[Guest ratchethack]

Say Keith - Sorry I called you, "Mitch"! Any chance y'er from the Wolverine state?

 

Sounds like y'er probably right on track. I have no idea how to qualify the trust that others place in having someone else do any kind of work on their bikes (authorized by anyone up to & including Carlo Guzzi? ). And it's difficult to reverse-engineer what someone else has done through a 3rd party via a Forum post! But it's easy enough to check what's been done WRT sag settings by taking simple measurements per the instructions at the link I provided. I'd certainly do this if y'er at all in question about any aspect of handling - if for no other reason than just to get an idea what y'er workin' with.

 

My take is that if you've got speed wobbles, there's likely something lacking in y'er setup.

 

I'm a non-stop broken record on this, but I always urge anyone and everyone to set BOTH laden and unladen sags, front & rear. Again - there's ZERO possibility of achieving the superb (IMHO) handling the Guzzi was designed with unless you get 'em BOTH correct, and there's ZERO possibility of getting 'em both correct with the wrong spring rates.

 

I honestly don't know if there's any such thing as a "stock" fork height setting, though I think every one I've ever seen off the dealership floor has been set flush - that is, 0 mm. I figure the reason they do this is that they have to assume a huge variance in new-owner weight, passenger, and cargo loads, and setting it at zero yields the laziest steering possible with (at least in the case of the 40 mm Marz USD fork) hopelessly weak springs, and also puts the rider farther back on his butt, which most newbies seem to prefer(?!) - at least sitting on it on the showroom floor. . . .

 

Best of luck. Anything we can do here by way of advice that's always worth at least as much as you pay for it, and I just about guarantee it'll get done - one way or another!!!!

[dlaing]

a smaller tire in the rear and stiffer springs in the front are a good thing, but because of the change, you may need a lower front end, and stiffer springs in the rear (you may need 600lb springs, and be sure to lube the shock eyes as the Sachs are known to break)..

Lowering the triples 10mm seems to be a good start....I benefited from about a quarter inch.

Ratchet's advice, especially about sag is the key to good suspension set up.

[big J]

I've got cafe sport bars on risers.The steering damper has been off for about a year now.I've never had so much as a sniff of a speed wobble or any other kind of instability,so to state that there's an inherent problem is going too far.My yokes are about an inch down the fork legs which allied to the moonscape known as the road surface here should mean it's twitchier than a tourettes sufferer.

Some bikes may need a wee bit of adjustment,but the V11 is not,as far as I can see,any more unstable than anything else.

My race tuned Laverda Mirage had inherent handling problems,the V11 does not.

[Guest Mich-Guzzi]

I appreciate all of the info provided here. And yes, I'm from the Wolverine State!

 

I had thought that the original location was flush so it's nice to confirm it. But I have seen so many raised that I just wanted to check.

 

No question that making sure the sag is correct is necessary and will be accomplished soon. I've done the measurements many times before on most of my other bikes so I know the drill.

 

The wobble isn't really bad - certainly not like I used to get on my old SOHC Honda 750. It's just a vague feeling in the bars the faster I go. And it got worse after the bar risers and bar ends. So first I will raise the forks and give it a try. I will also check the steering head bearings which have never been checked before. And I may try the bike without the bar ends and see if they have any effect. Whatever I find, I'll report back.

 

It's a great bike and it just needs a tweak to be perfect.

 

Keith

[Guest ratchethack]

I appreciate all of the info provided here.  And yes, I'm from the Wolverine State!

Well, now I've gotta ask, Keith. I'm originally from East Grand Rapids. You?

I will also check the steering head bearings which have never been checked before. 

Don't know if you saw my post awhile back on this? I adjusted mine at 10K mi. and again at 30K. Between the two, it had loosened up a half-turn (!) with no detectable looseness either on the road or on the stand - shaking it to check for looseness in the usual way revealed NO looseness prior to adjustment (!!) I torqued mine to ~20 ft-lbs., though you'll get an argument from at least one here who insists it's gotta be 15 ft-lb.!!

And I may try the bike without the bar ends and see if they have any effect. 

IMHO, this wouldn't be the primary problem, although the resonant frequency of the oscillation may be affected by the amount of weight that far out from the steering head. . . . . and the bar shakes without 'em ain't no picnic, either. . . . .

Whatever I find, I'll report back.  It's a great bike and it just needs a tweak to be perfect.

By all means please do. Andy y'er preachin' to the choir on that last!!

[Guest Mich-Guzzi]

Well, now I've gotta ask, Keith.  I'm originally from East Grand Rapids.  You?

 

- I'm located just north of Detroit in the samll town of Fair Haven.  But I spend a bit of time over near Grand Rapids at Grattan Raceway.

 

Don't know if you saw my post awhile back on this?  I adjusted mine at 10K mi. and again at 30K.  Between the two, it had loosened up a half-turn (!) with no detectable looseness either on the road or on the stand - shaking it to check for looseness in the usual way revealed NO looseness prior to adjustment (!!)  I torqued mine to ~20 ft-lbs., though you'll get an argument from at least one here who insists it's gotta be 15 ft-lb.!!

 

- I saw it and that's what got me thinking about it.

 

IMHO, this wouldn't be the primary problem, although the resonant frequency of the oscillation may be affected by the amount of weight that far out from the steering head. . . . . and the bar shakes without 'em ain't no picnic, either. . . . .

 

- I wasn't thinking about the weight.  As the Napoelons are fairly large, I wondered if they were affected by the wind.  Probably a long shot.

 

By all means please do.  Andy y'er preachin' to the choir on that last!!

94575[/snapback]

- Will do!

[Guest ratchethack]

Heh, heh. . . . . . Grattan raceway brings back a flood of memories through the fog of time, circa 1965.

 

As I recall, it was a dirt track back then, and I haven't been back since. Now vintage Guzzis are taking honors on a semi-regular basis, according to the latest reports at GuzziTech.

[Paul Minnaert]

what I see in the workshop manual for the 1999/2000 biles is that the forks are flush mounted with top of the triple clamps. And the cap comes just above it.

[Guest Mich-Guzzi]

Update as of Today:

 

Dropped the forks 10mm from the clamp to the cap split line.

Rotated the bar risers forward a bit.

Checked the sag number:

- Front unladen .75 inch Front with me onboard: 1.0 inch (.25 more than unladen)

- Rear unladen .25 inch Rear with me on board: 2.0 inch (1.75 more)

 

Intial test ride reveals problem is solved. No headshake so far up to 110 MPH. Need a longer ride to confirm but look's like its fixed.

 

My Theory (mine only!!)

From the sag numbers, it looks like it is a bit stiff up front and still a bit soft in the rear. With the smaller tire and the weight distribution change, weight on the front tire was a bit low. I later took two clicks of compression damping out and noted a bit of further improvement. Will also bump up the rear preload a bit. I have not yet checked the steering head bearings - although I did do the normal test of pulling the wheel back and forth with the wheel off the ground. No play and very smooth and light rotation force. It will get checked in more detail when I have a bit of time. But the change is simply amazing.

 

MANY THANKS FOR THE HELP! Now I am off to the Dragon for a bit of fun

 

Keith

[Guest ratchethack]

Update as of Today:

 

Dropped the forks 10mm from the clamp to the cap split line.

Rotated the bar risers forward a bit.

Checked the sag number: 

  - Front unladen   .75 inch  Front with me onboard: 1.0 inch  (.25 more than unladen)

- Rear unladen  .25 inch   Rear with me on board: 2.0 inch  (1.75 more)

 

Intial test ride reveals problem is solved.    No headshake so far up to 110 MPH.  Need a longer ride to confirm but look's like its fixed.

Keith, please keep in mind that as always, all advice you get from me is worth exactly what you pay for it, or only possibly something more. I have no professional qualifications whatsoever for any kind of motorcycle work other than maintaining and/or rebuilding a dozen motorcycles since age 12 over probably something approaching two hundred thousand miles on the road and a whopping unknown number of miles offroad. I do not intend to represent myself here as anything other than a motorcycle owner on a Forum. I do not intend to confuse anyone, nor do I intend to start an argument. I cast no aspersions on the expertise of your trusted chassis tuner. I am only following the objectives of suspension setup the way I understand them from my own extensive study and first-hand experience, and the following is merely intended as a GUIDE.

 

MORE DISCLAIMERS AND CAVEATS!

 

I assume the measurements you provided are accurate. There will almost certainly be disagreements from the Forum - and elsewhere. Those who disagree may be either (or both) vastly better informed and vastly more experienced than myself, and/or vastly less informed and vastly less experienced than myself.

 

NOTE: IT IS VIRTUALLY IMPOSSIBLE NOT TO ATTRACT DISAGREEMENTS OVER THIS KIND OF CALCULATION ON ANY FORUM OR FROM ANY SUSPENSION TUNER OR (ESPECIALLY) FROM ANYONE WHO HAS INVESTED EITHER GREAT AMOUNTS OF TIME AND/OR MONEY ON, AND/OR HAS MANAGED TO DEVELOP AN EGO THAT HAS BECOME WRAPPED UP IN SUSPENSION.

 

and finally,

 

NO TWO SUSPENSION TUNERS WILL SET UP A MOTORCYCLE EXACTLY THE SAME WAY BY THE NUMBERS!

 

Now then:

 

I converted your measurements to mm for simplicity thusly:

 

YOUR MEASURED SAG SETTINGS

 

Laden: F = 25.4 mm R = 50.8 mm

Unladen: F = 19.05 mm R = 6.35 mm

 

I used the following "GOAL" sag settings from the general rule of thumb:

(Laden = 30% x 120 mm = 40 mm, Unladen = 15% x 120 mm = 18 mm):

 

GOAL SAG SETTINGS

 

Laden: F = 40 mm R = 40 mm

Unladen: F = 18 mm R = 18 mm

 

NOTE: The general rule of thumb used immediately above may include a +5% range on each figure, depending on personal preference, but I left this out of my calculations for simplicity in this post.

 

Critical measurement - the GOAL DIFFERENCE between laden and unladen sags, for both front and rear, is 22 mm. Deviation from this indicates that spring rate is either too high or too low. A positive deviation indicates spring rate is too low. A negative deviation indicates spring rate is too high.

 

CONCLUSIONS:

 

1. The fork spring rates are far too high for your weight.

 

2. The rear shock spring rate is far, far too low for your weight.

 

3. The above two points add up to a particularly poorly balanced suspension.

 

4. No preload adjustment will put either front or rear suspension close to the proper ranges with these springs.

 

SUGGESTION: If this is at all of concern to you, I would certainly seek to confirm or deny these findings by whatever means available. If at all possible, I would discover the rates on the springs that you have and "extrapolate" via percentages to arrive at correct target rates. I would most certainly and without any question replace the springs, both front and rear. I would also certainly have a practical, sensible, and possibly slightly better informed discussion with your suspension tuner, solicit his input, and then make a decision about a next course of action.

 

I only suggest consideration of the above in the hope it helps, my friend.

[Guest Mich-Guzzi]

I do truly appreciate all of your input. Your conclusions are valid - given the accuracy of my measurements. I will measure again with a better helper to make sure the measurements are more accurate. Especially the front differential. The bike does not seem that stiff up front.

 

And I do plan to have a more informed discussion with my tuner. Rear spring rate for me is always problem. At my weight, I always have trouble finding a high enough rate spring and usually end up with whatever the highest rate they can get. Which can sometimes be not to well balanced with the front rate. But we will see what is available.

 

I do have one question: Is the full suspension stroke the same front and rear (120mm)

 

Keith

[Guest ratchethack]

I do have one question:  Is the full suspension stroke the same front and rear (120mm)

 

Keith

For practical purposes, yes - unless you consider the compression of the rear shock "doughnut", which potentially adds another 4-6 mm.

 

In your case, you might want to fully consider this in your measurements - at least as long as you're continuing to bottom out.