"old" V11 sport frame

[Guest ratchethack]

I, for one, think there are problems with the old frame.

Guido, I recall your posts here after your crash. You may recall my comments in reply at the time.

 

With all due respect, there were many valuable lessons to be learned from your experience that you seem to've missed. Please do the Guzzi community a favor and do not continue to spread unnecessary fear, misunderstanding, and ignorance by perpetuating the old wive's tale about the "short frame" Sport!

 

With all due respect, Part II, your bad experience DOES NOT correctly confer upon you an understanding that your crash was due to a mysterious defect in the design of the motorcycle. On the contrary, your posts suggest a considerable lack of basic understanding of motorcycle suspension, and most significantly, a lack of understanding of the safety and responsibility of getting it properly set up. You have no basis for having made many of the false statements that you've made - both then and now.

 

From my questions to you after your crash, it became instantly clear that you had no idea whether or not your Guzzi had been correctly set up with proper spring rates, preloads, and BOTH laden and unladen sags - OR height of the stanchions in the triple clamps. Since the 40 mm Marzocchi USD fork comes with ~.6 kg/mm springs, which are only properly rated for a rider of 125-150 lbs., heavier riders easily overwhelm the suspension. The rear is similarly undersprung, as discussed on this Forum ad nauseum. This can indeed be extremely dangerous on an uneven surface, especially when the sag settings are at best UNKNOWN and at worst, completely off the charts! I have to assume from your posts that your Guzzi was never properly set up, and that you had no idea either if or how badly. . . .

 

Not having enough knowledge and experience to understand what caused your crash is no reason to suspect that the "short frame" Sport is either "haunted", possessed by the infamous "skid demon" from the '60's Honda manual, or plagued by vague and mysterious engineering flaws that would cause it to somehow spontaneously crash without provocation! As I recall, this is approximately the way you characterized your crash. This is exactly how poorly substantiated rumors get transformed into persistent "old wive's tales"!!!

 

ANY motorcycle not correctly set up with spring rates matched to load will have handling problems. This is particularly dangerous for an inexperienced rider. Again - there's NOTHING about the geometry of the Sport frames that is either radical, out of the ordinary, or dangerous! As I've pointed out, the geometry of the "short frame" Sport is relatively mild relative to today's far steeper-raked Sport bikes. The short frame Sport is both quite "long", and "lazy" steering in comparison.

 

The fact that the factory added gusseting to the frame in later models does NOT mean that the earlier non-gusseted frames can suddenly "cause a crash" on an uneven, bumpy, or rippled stretch of road - or even a twisty one, for that matter! These afterthought stiffening stays were admittedly signs of a poorly-planned and poorly executed chassis (by today's HyperBike standards, anyway) and were attempts to improve handling at the outer limits of performance - but they ARE NOT signs of prior inherent danger or instability of the chassis for common road use - even under the hardest road riding!

 

The Sport frame and its variants, both "short frame" and "long frame", as well as the LM and its variants, while not remotely comparable to the track-inspired chassis designs of today, are among the MOST ROCK-STABLE chassis on the road - but they're all as unpredictable and dangerous as any other motorcycle would be if equipped with the wrong springs for the load and incorrect sag settings. If the springs and sags are far enough out of whack, there are very few more effective ways to make an otherwise superbly handling motorcycle more dangerous on the road!!!!!

 

I will agree with you on one aspect of this ONLY - ignorance and neglect of suspension setup on the Guzzis with the stock springs that came with the Marz forks (including but not limited to the short frame Sports) is likely more dangerous than with other Guzzis that come from the factory with higher-rated springs (such as the ~50% higher rate springs that came with the Ohlins fork-equipped Guzzis). The higher-rated springs that came with the Ohlins forks would be far more suitable for average-weight riders. But again - this DOES NOT make either the Marz fork OR the "short frame" Sport inherently dangerous or in any way inferior!!!!

 

It seems that many first-time riders today are very poorly advised about the critical importance and basic safety aspects of suspension setup. They often seem to expect to be able to ride out of the dealer like they would drive a new car, without a thought about suspension whatsoever! One poster here awhile back actually posted something to the effect that since he paid the dealer so much for his Guzzi, this should excuse him from having to think about suspension setup!!!!! IMHO, dealers who allow this kind of typical "This is my first motorcycle!" customer ignorance to leave the premesis of the dealership with their motorcycles are at least partially at fault and IMHO they should be held liable for resulting injuries unless they've at least reviewed the basics of suspension setup with the new owner, preferrably with reference to the owner's manual. Lacking this, such ignorance results in a rider who is a potential danger to himself, a menace to others on the road, and in fact a menace to the entire sport.

 

Ultimately, the responsibility of understanding and ensuring suspension setup resides with the rider alone. ANY RIDER of ANY MOTORCYCLE owes it to himself for his own well-being, for his own enjoyment of riding, and for the safety of those with whom he shares the road to educate himself on this most basic safety aspect of motorcycling. For God's sake, if a rider can't or won't understand how to set it up correctly himself, he best get a reputable Pro to do it for him!!

 

Many experienced riders who own "short frame" Sports, myself included, have logged tens of thousands of miles, in some cases into the hundreds of thousands of miles, on demanding roads of every possible description and at every possible speed without as much as a trace of the "inherent danger" that you have been implying exists with these motorcycles - and without any hint of the symptoms of evident neglect and ignorance that resulted in your crash.

 

Please spend some time reading and learning, inform yourself, and stop passing on bad information to other riders. You'll find a wealth of very good information here on this Forum.

 

Sorry to be so blunt. Rant mode off.

[jtucker]

As my cornering skills on the V11S improved and I got faster, I began to notice some pretty scary sensations when corning. I guess it was "push" or "understeer" that I was detecting... just sort of felt like the front tire was losing traction and going wide in the turn. Scary. So much so that I pretty much decided I was going to get rid of the bike if I couldn't sort it out.

 

So, I read Todd Egan's write-up on tweaking the V11S suspension (which can be found here) and subsequently had an email chat with Todd. This convinced me to give it a try. Note that his tips not only suggest damping adjustments, but also raising the forks up in the triple-clamps a bit.

 

The difference was night and day. It was like a completely different bike! In fact, the week after I made the change, I was on an unfamiliar road and found myself going into a downhill switch-back "way too hot". I lremember leaning on the bars and yelling "OH SHIIIITTTTT!!!" as I went through the turn. Remakably, I made it through with no problems (other than a pucker mark on the seat). I'm convinced that if I would have taken the turn a week earlier with the stock suspension settings, I would have crashed - no doubt.

 

So, if you haven't seen it yet, check out his article. It sure helped me!

[Guest ratchethack]

So, if you haven't seen it yet, check out his article. It sure helped me!

It helped me too. After reading it, I found that if I got way forward over the bars to offest the rearward weight bias when approaching the limits hard-over on mountain roads, the front end wouldn't push, and it became very neutral. With suspension properly dailed-in, it was instantly a brand-new world of handling. Getting up over the front wheel is a habit now. Todd's a great resource. I got my Wilbers fork springs from him, and this has been among my "cheapest" upgrades in terms of cost-to-value.

 

What was "new" then is no longer new, but as I've commented to Todd, I found his choice of the word "problem" in paragraph 2 of his analysis to be - errrr, somewhat unfortunate. I see he still hasn't changed it. . . . .

 

He also missed an opportunity to at least mention the importance of matching spring rate to load, which IMHO, belongs in that link. . . .but it's a topic that requires detailed attention and focus. As Carl pointed out in post #3, Ed Milich has some good basic stuff on it elsewhere on GuzziTech.

 

One of the best links I've found on chassis setup is this one:

 

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

[Ballacraine]

One facet of the equation, mentioned by Ratchet IIRC, but not expanded upon was the variable of load caused by the mass of the rider.

 

There are boatloads of variables, all important in their own right, that all have differing levels of effects, but I feel that this is a significant one.

 

On a few occasions in the past I have had handling problems with bikes that my bigger heavier friends have not had on similar bikes....and vice versa.

 

All have been sorted with varying degrees of success by using a patient, analytical approach. Some have been sorted with steering dampers, others with dropping or raising front forks, changing spring rate, tyre changes etc., some even with riding posture. Most of these occurences were on bikes with suspension with very limited if any adjustments provided, other than preload on the rear.

 

Yes, these technical articles are VERY useful and in some cases invaluable, but please, change ONE variable at once, then you can attribute the improvement or deterioration to that single change.

 

Otherwise you will be prolonging the agony!

 

Nige.

[Paul Minnaert]

Then there is the rear swingarm, where later machines have a stiffener welded on, and maybe, if I remember correctly  a change in length?

 

All spines have a 40cm long swingarm, from daytona to the last v11. All v11 swingarms have same measurments. NO extra stifner.

 

My daytona has a much more extreme geometry, feels quick steering but never out of control. It might be a combination of things, that make the first v11 stock not as good handeling as it could have been. What made a bad press to start with, and the new owners aprilia "solved" it. So made the frame 5 inch longer, a lazy headangle to name two.

They did some good things, the front engine triangle is stiffer, and the mounting between engine and gearbox/swingarm is a good one too.

 

But if you bother, why don't make a set lower frame rails, like a tonti. It's pretty easy, not sexy but I think it works, for all spines. You can find an example on Stan Friduss sport 1100.

 

http://www.guzzitech.com/racers/stan5.JPG

[Guest ratchethack]

But if you bother, why don't make a set lower frame rails, like a tonti. It's pretty easy, not sexy but I think it works, for all spines. You can find an  example on Stan Friduss sport 1100.

Paul, this is a great suggestion, and I've been thinking about it myself. It's a great "someday" project for me.

 

But for most riders who haven't as much as touched their stock suspension , I believe that simply learning how to make their Guzzi handle as well as it was designed to handle by re-springing properly is about as cheap and easy as such a tremendously positive transformation in handling and safety could possibly be.

 

No amount of frame rail stiffening can possibly make up for poor chassis setup!

 

Doing BOTH would likely be about as good as it's ever gonna get, IMHO.

 

BAA, TJM, & YMMV

[BrianG]

But if you bother, why don't make a set lower frame rails, like a tonti. It's pretty easy, not sexy but I think it works, for all spines. You can find an  example on Stan Friduss sport 1100.

 

94192[/snapback]

 

This might make an interesting project but unless I'm way off on my observation of the Spine Frame engineereing, MG designed the engine, in this application, as a stressed frame member, as opposed to designing it as a passenger power-unit carried in a cradle. As such, extra frame rails would contribute little to the overall stiffness of the frame.

[Paul Minnaert]

Brian,

The engine was never intended to be used as a stressed part. Ok it works. The spine itself is very weak. Try this with bike on stand, remove the 2 front engine/frame bolts, and move a bit with the front wheel left to right, notice the place where you just took the bolts out.

The steeringhead swingam connection should be inflexible. And with the lower rails there is added strenght to the swingarm mounting. The >2002 has added strenght there too. Even without the bars to the engine there is a gain because of the extra cross bars.

[mdude]

stiffening and helping out the poor old engine ca n only be a good thing. Remember these? from a japanese site some time ago. they seem fairly easy to make, dont they?

[Ballacraine]

HHmm that is interesting mdude.

 

Do you have larger pics, please?

 

Nige.

[BrianG]

Brian,

The engine was never intended to be used as a stressed part.

 

Why do you say this?

 

 

 

The spine itself is very weak. Try this with bike on stand, remove the 2 front engine/frame bolts, and move a bit with the front wheel left to right, notice the place where you just took the bolts out.

 

If removing the engine from the rest of the frame removes some structural rigidity, the engine is being used as part of the frame to provide that rigidity, hence IS a stressed member. Any isolated portion of the stress carrying system might well be weak in isolation.

 

 

The steeringhead swingam connection should be inflexible.

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This assumption is inaccurate. Motorcycle frame design is aimed at providing torque and vertical deflection rigidity, but lateral rigidity is not desirable. Some lateral deflection is desired to provide additional suspension deflection while leaned over. This is because the vector of vertical suspension compliance decreases with increasing lean angle. The requirement for suspension compliance relates to the stability of the contact patch of the tires.

[Guest ratchethack]

This assumption is inaccurate.  Motorcycle frame design is aimed at providing torque and vertical deflection rigidity, but lateral rigidity is not desirable.  Some lateral deflection is desired to provide additional suspension deflection while leaned over.  This is because the vector of vertical suspension compliance decreases with increasing lean angle.  The requirement for suspension compliance relates to the stability of the contact patch of the tires.

What's your vector, Victor?

 

Sorry, couldn't resist.

 

This is most interesting. I've always assumed what Paul said about the paragon of chassis deisgn being absolute rigidity between steering head and swingarm pivot.

 

Brian, I don't follow you when you say, "the vector of vertical suspension compliance decreases with increasing lean angle."

 

When a motorcycle is hard over, close to dragging hard parts in a high-speed sweeper and hammering across a rough surface, the vector of G-thrust through the chassis and suspension is nearly - but not quite - in line with the vertical axis of the chassis. The only deviation from absolute vertical from the frame of reference of the chassis is due to the offset of the contact patches, which I have to imagine is a relatively tiny angle WRT the direction of the major G-thrust vector. Now are you saying that lateral chassis flex is desirable to provide lateral compliance or "flex" to deal with this relatively tiny offset of the contact patches?

 

I ain't no engineer, and this certainly could well be, but it doesn't quite seem reasonable to me that the slight lateral vector of the mostly vertical (to the chassis) G-forces would be significant enough to have to be attenuated with flex?!?!?!

 

Enquiring minds just gotta know!

[Tom M]

RH,

FWIW in Lee Parks book Total Control, High Perfomance Street Riding Techniques, he says "At higher lean angles motorcycle suspension becomes less efficient because the moving parts are no longer perpendicular to the forces being applied to them. In essence, the spring rates become progressively stiffer, and the sideways forces cause sliding parts to flex against one anothercausing additional friction. To counter these inefficiencies motorcycle engineers design in a "tuned" amount of chassis and tire flex. This is helpful because at maximum lean the frame and sidewall are at a better angle to absorb bumps in the road than the suspension system."

 

He also has chapters on suspension setup and chassis tuning that I'm sure you would enjoy

 

(I bought the book before a recent camping trip to bone up on proper street riding technique before heading to the mountains with a group of guys who have been riding the street for decades. I know how to go pretty fast in the dirt but the road is a lot different. I might have kept up without reading the book but it really helped my confidence knowing what I'm supposed to be doing when heading into a blind bumpy downhill corner at 85mph )

[Guest ratchethack]

Thanks Tom. This explanation makes perfect sense. NOW I GET IT!!!

 

The key being thinking about the side-loading relative to the chassis as the frame has to deal with bumps generating lateral forces when leaned-over.

 

Sounds like another great book that I'd get lots of benefit from reading, but wouldn't likely find enough time for. But I always appreciate a good book referral.

 

knowing what I'm supposed to be doing when heading into a blind bumpy downhill corner at 85mph

Shouldn't be much of a prob for a dirt rider. . . . .

 

Now throw in 5 degrees off-camber and decreasing radius with snow-melt running across the tarmac and a 1,000 foot drop for a shoulder -- and you've got some new kinda fun!

[Ballacraine]

Thanks Tom.  This explanation makes perfect sense.  NOW I GET IT!!!

 

The key being thinking about the side-loading relative to the chassis as the frame has to deal with bumps generating lateral forces when leaned-over.

 

Sounds like another great book that I'd get lots of benefit from reading, but wouldn't likely find enough time for.  But I always appreciate a good book referral.

Shouldn't be much of a prob for a dirt rider. . . . . 

 

Now throw in 5 degrees off-camber and decreasing radius with snow-melt running across the tarmac and a 1,000 foot drop for a shoulder -- and you've got some new kinda fun!    

94319[/snapback]

 

Could I just add a large quadruped ruminant around a blind corner?

 

Nige.