Red (short) Frame vs. Black (long) Frame

[Chuck]

5 hours ago, docc said:

That is an interesting perspective. When the frames changed, not only longer but with the cross-braced front and rear subframes and lower braces across the gearbox (along with the wider rear wheel/tire), the thinking was that this was all in response to persistent complaints in the press about the odd handling characteristics of the early Sports. While some of that was down to "expectations of what a Guzzi handles like,'  there were a collection of very real issues that affected the early Sport's stability and tendency to "weave" at high speed in a cross wind (like passing a truck on the freeway).

It occurs to me the LongFrame was introduced for the 2002 LeMans, still with the early tank style (external pump/fiter), while the Gen2 tank came out in 2003, if I am not mistaken (?)

Correctamundo.

[knumbnutz]

I have the early frame with gearbox bracing and it shows no sign of instability.

Now Im putting that down to a couple of things but mostly weight distribution. 

On my modified bike I have a reasonable change in weight. The battery sits under the tank now and the subframe is about 1.6kg compared to 10+kg of the original, so it is now more bias on the front.

Years ago when I built my modified MilleGT, I did a similar lightening job, overall reducing about 35kg off it. But the weight loss was both front and back.

I assembled it with the same rake and trail as the original and it was very unstable, every bump out of a corner would give a small headshake, to the point I was considering a steering dampener as at this stage I'd only ridden it around the block.

I dropped the triple tree over the forks by 12mm and it was a totally different bike. Better steering, stable, no headshake or weave at any speed. 

[Scud]

11 hours ago, knumbnutz said:

Actually I have to disagree..

The tank is the part thats 20mm longer. All guzzi have done is hide this by making to frame fit the longer tank. Mario on the production line made the longer tanks to fit the fuel pump and simply got luigi who makes the frames to cover for him. 

So it's no tanks to mario 

 

I have personally swapped tanks between red and black framed bikes without any issues or modifications. While I no longer have both tanks available to measure, I do believe the tanks are the same size. There is just more clearance between the tank and the triple-clamps with the black-frame bikes. 

[Lucky Phil]

9 hours ago, Scud said:

I have personally swapped tanks between red and black framed bikes without any issues or modifications. While I no longer have both tanks available to measure, I do believe the tanks are the same size. There is just more clearance between the tank and the triple-clamps with the black-frame bikes. 

I'm about to burst your bubble Scud and put this to bed forever and add to the data base.

I have 2 second hand and one brand new (never seen fuel) later tanks and 1 brand new (never seen fuel) old style tanks and the original on my bike.

I have just laid the tape measure on my original tank and brand new late tank and i can tell you they are dimensionally very different.

I'll post some images with tape measures attached so we can align with your frame length images. My feeling is that you could fit an earlier tank to a later frame but not the other way around without losing steering lock. My bike now has the modified fwd mounts fitted which reduces my steering lock anyway and if I fit the later type tank I'd end up with pretty much zero lock.So comparatively you loose quite an amount of fork leg to tank clearance on full lock when you fit the later tank to the earlier frame and from my experience of my bike with std mounts I only had 5mm clearance tank to fork leg anyway on full lock.

So ctr of aft mount bolt to fwd edge of tank....old style 620mm, new 660mm 

EDIT.....if you look at the front edge of the fwd mount you can see where the difference is. Note the extra length from the fwd tank mount forward edge to the fwd tank section where the tape is resting. It appears there is an extra 40mm here but the forward projections are about the same. I believe they have lengthened the top of the tank 40mm and moved the cap opening forward 20mm but the tank length overall is the same give or take.  

Note how in these images how the front forward projections seem to sweep back a lot more on the green tank than the grey later tank. This is in line with the overall length being roughly the same but the top face being extended forward to close the gap to the steering head around where the breather banjo is on the upper frame. Looks like scudd may be correct although I'd be interested to see if the later tank on the earlier frame limits the steering lock. As I said the later tank wont work with my new setup.   

Dont be fooled by the camera angle, centre of aft mount hole to ctr of cap, old tank 295mm, new tank style 315mm

315mm aft ctr mount hole to cap ctr.

Once again camera angle. Fwd tank edge in the ctr(not the projecting sides) to cap ctr 315mm, old style tank 295mm 

Old style fwd ctr edge to cap ctr 295mm

The dimensions from the back of the fwd mounts to the forward most edge of the tanks are virtually the same. So its like they sliced the ctr filler cap  section out of the tank fwd and aft and added two 20mm plugs to lengthen it. One fwd and one aft of the filler cap.

Just like when they stretch the fuselage of a heavy jet

Full sized images are in my album.

Ciao    

[footgoose]

At the risk of thread drift, and regarding tank sizes, are we talking about 2 different frames and 2 different tanks? I'm fairly certain 99 thru (early) 03 external pump tanks were all the same and were oem on red And black frames. The internal pump tank being on the (later) 03 -05. The internal and external pump tanks are different lengths, though I only eyeballed it. 20mm sounds correct as I recall having laid them side by side, and the extra length was forward of the neck cutout. I no longer have the 'internal" tank to check.

Thinking purely as a bean counter, MG had to recast the new tank for the inside pump anyway, possibly adding a bit of capacity to the front to compensate for the pump's space. Then why would they bother to change the frame?

 

sorry posted same time as Phil

[Kane]

2 hours ago, knumbnutz said:

I have the early frame with gearbox bracing and it shows no sign of instability.....

......overall reducing about 35kg off it. But the weight loss was both front and back.....

Wow, very interesting. A couple of questions, please: 

“gearbox bracing”, does this refer to the triangular bracket that is shown in the parts catalog diagrams yet is missing from so many red frame V11s? Something else...a mod?

How are you able to shave off 35kg? That seems like a lot! I would really love and appreciate to see or hear/read how this is done and results on these fun but a bit portly rides.

Thanks! 

[knumbnutz]

Wow, very interesting. A couple of questions, please: 
“gearbox bracing”, does this refer to the triangular bracket that is shown in the parts catalog diagrams yet is missing from so many red frame V11s? Something else...a mod?
How are you able to shave off 35kg? That seems like a lot! I would really love and appreciate to see or hear/read how this is done and results on these fun but a bit portly rides.
Thanks! 

The MilleGT is basically a California. There's heavy junk on it everywhere.
I got rid of everything that wasn't necessary, then used a fibreglass front guard, tank and seat. Used a smaller powerful and lighter battery and shaved 4.5kg off the flywheel.
On the V11, I made a light aluminium subframe and only a single seat.

Sent from my ELE-L29 using Tapatalk

[docc]

1 minute ago, Kane said:

Wow, very interesting. A couple of questions, please: 

“gearbox bracing”, does this refer to the triangular bracket that is shown in the parts catalog diagrams yet is missing from so many red frame V11s? Something else...a mod?

How are you able to shave off 35kg? That seems like a lot! I would really love and appreciate to see or hear/read how this is done and results on these fun but a bit portly rides.

Thanks! 

The "triangular brace" (between the bottom of the SpineFrame and the top junction of the engine/gearbox) that went missing on the V11 is only fittable to the early Sports 1999-2001, but that is not the LongFrame "gearbox bracing." This is two tubes extending from the lowest tip of the frame side plates (from the lower subframe) forward to the back of the engine case. This cannot be added to the early Sports as there is no boss to attach the brace tubes to the engine. Look for the tube in this Scura image just above the exhaust:

[Kane]

Thanks very much, docc. I see it clearly from your pic and description. From what I have gathered from reading numerous posts here, it seems that people feel that the red frame triangular brace reduces the chance of the gearbox case cracking (I have been told that the cracking occurs at a spot where the case is milled thin). 

Does the bracing on either the red or black frames help with handling? I read knumbnutz as qualifying his well behaved red frame bike to the great box brace.  Is that the purpose for the braces on the black frames? Do the black frame tubular braces serve the same function in terms of protecting the case and/or handling as the red frame triangular bracket brace, the one often missing from our early V11 bikes? I wonder why Guzzi would omit it on so many of the red frames, and then reintroduce something similar on the black frames. 

[Lucky Phil]

1 hour ago, Kane said:

Thanks very much, docc. I see it clearly from your pic and description. From what I have gathered from reading numerous posts here, it seems that people feel that the red frame triangular brace reduces the chance of the gearbox case cracking (I have been told that the cracking occurs at a spot where the case is milled thin). 

Does the bracing on either the red or black frames help with handling? I read knumbnutz as qualifying his well behaved red frame bike to the great box brace.  Is that the purpose for the braces on the black frames? Do the black frame tubular braces serve the same function in terms of protecting the case and/or handling as the red frame triangular bracket brace, the one often missing from our early V11 bikes? I wonder why Guzzi would omit it on so many of the red frames, and then reintroduce something similar on the black frames. 

I suspect the later lower gearbox brace was needed as a result of changing the front engine support frame. I dont think the later front support frame offers the same degree of longitudinal control of the engine and therefore they added the rear longitudinal additions under the gearbox.

With Guzzi I personally think you need to understand that there is some other sort of engineering rationality going on at this time. The additional cross brace added at the new gearbox mount that you can see only in the parts diagram is another example of added structure that doesn't seem to have any function. This is an engineering and design department that seemed to think that all their bikes needed to be engineered to drag sidecars and or trailers around. Some things they did at this time made no engineering sense at all.

 

Ciao

[docc]

Agreed. A sort of "knee-jerk" solutionism.  Perhaps not actual engineering at all. Maybe just > changes to demonstrate response to the market < 

[docc]

On the omission of the "triangular" spine frame brace, I firmly believe they just found it too labor intensive to fit after the fuel injection was installed. If you have ever fit one (to an FI SpineFrame), you know what I mean . . .

[Lucky Phil]

17 minutes ago, docc said:

On the omission of the "triangular" spine frame brace, I firmly believe they just found it too labor intensive to fit after the fuel injection was installed. If you have ever fit one (to an FI SpineFrame), you know what I mean . . .

Yes docc they are a bastard to fit for sure even with the bike half disassembled.

Ciao

[Chuck]

9 hours ago, docc said:

Agreed. A sort of "knee-jerk" solutionism.  Perhaps not actual engineering at all. Maybe just > changes to demonstrate response to the market < 

I've seen several cases of what I call "afterthought engineering" on Guzzis. The Centauro was particularly bad about that. That's ok.. it's Guzzi. One of their endearing qualities is that you can tinker with them and make them better.

[Scud]

Hey Phil - no worries about bubble bursting, especially if you are providing evidence.

It's clear that the internal-pump tank is longer, which I did not know.

My experience was in swapping a Greenie tank with a Champagne LeMans tank. This was red-frame to black frame, but both tanks had petcocks and external pressure regulators, supplied by an external fuel pump. 

So... I still believe that the external-pump tanks were the same size through 2002 (same as Footgoose said above). Then they were different starting in 2003 with the internal pumps. (With the customary footnote for the bikes sold as 2003 models, which were more like the 2002 models).