Front crossover / balance pipe

[Martin Barrett]

Bill,

mine fractured (4K) and the only thing I'd none was fit the Techno bag mounts, disturbing the can mount only.

Since then I've had no end of fun trying to get it to cinch down tight on the standard gaskets. I've had to replace the bolts and drums with the ones out of the header/collector clamps and have non standard clamps there now. I've tried the shims but couldn't get a good rattle free seal.

 

But my biggest current problem is the collector/can joint. I've always had a wobbly can (not evident to me whilst riding) Big J and Baldini both had goes at it, tightening and even shimming the clamps. The problem now is that it's thinned out the metal. This wobble has no doubt lead to the mounting brackets braking.

 

Some when I'll be forced to replace the whole system. I like twin cans and not looking for extra noise/performance

 

A lot of mine are chicken/egg issues

[Guest ratchethack]

. . .

So, am mystified--a state I inhabit frequently--how your friend's LM has had 'em welded without fractures. That would be inconvenient as it might mean I'm wrong.

 

Bill

Ah, Mystic -- I recall a blustery, sunny afternoon in September on the wharf -- no, that was in Conneticut, sorry. My stompin' gounds continue to be the Great State of Continual Amazement, but that's another story altogether, and you don't wanna get me started. . . .

 

The "solution" was to seal up the ends of the "spigots" off the headers with flat, circular plugs welded in.

 

-- And Bob's y'er dear mama's sister's husband (He is, in fact, mine -- and wot a guy!).

 

WRT your comments, Bill -- He had (and still has) repeated multiple cracking of the headers up by the heads -- away from the crossover -- before and after eliminating the crossover. He's convinced lately that running too lean has overheated the headers and induced the fracturing, which, IMHO, is a distinct possibility. Previously, we'd both been operating under the theory that the cause of the headers cracking had been the fact that he had no rubber mount support for his Stucchi crossover, but he had that fixed and the header cracking continued...

 

YMMV

[Ryland3210]

No worries, my friend!

 

 

If you need something to work on and want to be really productive, howzabout givin' y'er Guzzi her only chance of handling the way she was designed to handle , and set up y'er suspension?

 

Enlighten me, please. With the Ohlin's already there, what's to be done in terms of set up?

 

The Cafe Sport has the crossover under the belly, so how much difference would locating them closer to the exhaust ports make? Is it anything nearly as critical as 2 stroke exhaust tuning is?

[Guest ratchethack]

The Cafe Sport has the crossover under the belly, so how much difference would locating them closer to the exhaust ports make? Is it anything nearly as critical as 2 stroke exhaust tuning is?

John, there are different purposes for crossovers close to the head vs. further downstream. The crossover close to the head is for the purpose of improving midrange performance when running increased valve overlap, though on my Pal's '04 LM, eliminating it made no perceptible difference on the seat-o'-the pants dyno. The waters get deep real quick when it comes to exhaust gas flow dynamics in the case of twins and multi's, where crossovers can be used to achieve different power and torque characteristics by harnessing additive and reflective wave physics. 2-strokes are in a different league altogether here from 4-strokes, and far more critically dependent on precise engineering of wave pulse dynamics for achievement of optimum cylinder filling. That's all I'm gonna say on this, lest I rapidly assume hoof-in-mouth posture.

 

Now then. Setting up suspension!

Enlighten me, please. With the Ohlin's already there, what's to be done in terms of set up?

It's a pleasure to find someone who's interested. Please forgive the usual overly-windy response. In case others might also be interested, John, I'll address this response to y'all.

 

It's become one o' my favorite saws, 'cause IMHO it's one sorely under-appreciated aspect of enjoying the the Guzzi on the road, and it's neglected far too often. I'm no expert on this, but I've read and studied a lot of the experts, and I've achieved excellent results by applying the principles I've learned. As always, I throw my analysis on the mercy of those reading this who're more knowledgeable than myself, who will hopefully correct any errors or statements they find misleading -- with my welcome and thanks!

 

Do I have my own Guzzi set up perfectly? Nope. But I'm about as confident as I can be that it's about as good as it's ever gonna get -- and that ain't too bad! IMHO, perfect suspension setup doesn't exist. It's a balance of compromises, and the Guzzi has a couple o' major suspension challenges that many other bikes don't -- a 20 lb. bevel drive and shaft in the rear hub, and significant rearward weight bias, to name 2 of many. Getting it correctly dialed-in is NOT a matter of precision. It's one o' those things that're like hand grenades. "Close enough" is as effective as it ever needs to be, and there's a considerable penalty f'er dropping it altogether!

 

As the esteemed Mr. Roper has said so often, lo these many years, the cost/benefit ratio here is far better than chasing curves on a dyno chart, and I agree in spades. A little study & effort is required. STUDY?! EFFORT?! Pshaw, you say! Y'er entire purpose f'er riding is to ESCAPE anything resembling STUDY and EFFORT!!! Well, Binky, I suggest that it's a highly configurable and adjustable chassis, and that there's a reason f'er this. Taking a flying uneducated guess at suspension settings carries risks, including your safety and that of others on the road. Speaking f'er myself, the quality of "the escape" I get from riding is directly proportional to the quality of handling the bike is capable of, and this doesn't ever happen by itself. Setting it up is exactly the kinda personal involvement with the machine that I find pays back big rewards on the road.

 

There are a couple of basic principles that are really very simple. Many riders seem to get over their heads with this stuff, and this is understandable, because some aspects of it are actually counter-intuitive. F'er example, unless y'er a flyweight, stiffer springs than stock typically provide a more plush, SOFTER RIDE, because they allow you to keep from bottoming-out without having to crank in excessive preload, thereby allowing far greater suspension travel! A little reading clarifies all, and there are some good "cookbook" approaches to setup that I've found very helpful (see links bleow).

 

The most important thing is to get spring rates matched to load. Guzzi's (including V11's) were shipped with varieties of different fork and shock mfgr components, many of which were in turn supplied with different spec spring rates for different importers. For my weight and riding requirements, my Sport was horrifically undersprung in the front (Marz 40 mm USD fork), and moderately undersprung in the rear (Sachs-Boge shock). I've up-rated springs at both ends and installed a custom-order shock. From what I gather, the Ohlins equipped Guzzis have significantly higher-rate springs than the ones I got with mine. I believe the standard-issue springs in the Ohlins-equipped Guzzis are more likely to be a closer match to the load requirements of average riders. This doesn't automatically mean they're "the best" rate springs for everyone, nor does it mean they don't need to be correctly rated for the load!! The principles at work here apply to all bikes, all components, and all riders!!!

 

If y'er a Big Guy, y'er more likely to have more of a mismatch with stock springs, regardless of supplier. I've discovered that a surprising number of Guzzis are hopelessly undersprung for their riders and overall loads. Many riders don't seem to notice that they're riding around on a tiny fraction of available suspension travel. Many are riding mostly within the last inch of fork travel on the air spring in front, and often the only thing separating them from suffering frequent metal-to-metal impact at the rear is a severely bludgeoned rubber shock bumper! This, my friends, is a HARSH ride! Even more have never touched preload settings, and many don't seem to have as much as a clue why they'd ever want or need to. Now this is just me, but when I see this, particularly on a Guzzi, I gotta wonder how the rider ever finds any enjoyment in waltzing a sow when they could be doin' the tango with a bit o' a Temptress. . . .

 

For me, getting it right defines the entire character of the Guzzi on the road. Only when you get things within the ranges that the engineers designed the bike to operate within is it possible to achieve the handling it's capable of. Anything too far outside of these ranges, and you ain't got a chance of realizing wot the engineers put into it. OK, whinge mode OFF.

 

Once you establish parameters for the right spring rates and get them installed, you can set laden and unladen sags. It's critically important to get BOTH in the correct target ranges, and this isn't possible with a poor match of spring rate to load. Wot's left after that is all secondary, IMHO. I think of the rest -- compression & rebound damping rates, rake & trail via fork tube height, and air gap in the fork -- as "fine tuning".

 

That's about it. I've found that the why's and wherefore's are pretty well covered at these links, which taken together, IMHO make for a fairly good overall guide:

 

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

 

http://www.racetech.com/articles/SuspensionAndSprings.htm

 

http://www.peterverdonedesigns.com/oilheight.htm

 

Hope this helps.

[Ryland3210]

 

I recall a study done by some SAE member college students on a wide variety of exhaust systems used on 2 stroke engines. The variation in shape of the torque curve and power production was considerable.

 

I also did some analysis and experimenting with header designs of my own for my earlier muscle cars. I must wonder about the effectiveness of crossovers connected to exhaust pipes at right angles, so I'm not surprised by your comments. One of the most effective designs I've seen was the four into one used on the original Kawasaki 1,000 CC superbike. The four equal length tubes didn't simply dump into a large diameter can, as did most aftermarket headers for cars. They took the fact that the exhaust pulses arrived in sequence, and did a pretty good job at maintaining cross sectional area at the point they joined, then diffused into a megaphone. Power production was terrific, and the sound was a wonderful, fierce, unearthly howl.

 

Thanks much for the links on suspension setup and your entertaining prose.

 

Have you ever considered publishing? I think you have real talent, and probably applicable to a variety of topics.

[Guest ratchethack]

Por nada, mi compadre.

 

Thanks f'er the comments.

 

Now I wouldn’t want to come off like some kinda suspension snob here. Heaven forfend!

 

Leave us by all means be an inclusive, Big Tent kinda Forum at all times. For all our riding Pals whose entire consideration of suspension is and always will be limited to such things as the color of shock springs and the nice Ti-nitride coating on the forks, we have alternatives!

 

With that in mind, here’s a suspension setup philosophy that has gained tremendous popular support in recent years, and certainly has a large following.

 

The Compleat OCC Suspension Setup Guide

 

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