V11 Modifications - Opinions?

[Guest ratchethack]

Good point.

Ratchet, I apologize for giving a f@ about your pal wanting to put hi-comp pistons out of his bike.

You and Pete do make some points that have some RELATIVE validity, and possibly some absolute validity that time may prove.

 

One more question for Ratchet and Pete:

Do you think it was a mistake for Guzzi to go to higher compression pistons in 2003/2004?

They allegedly upped the compression from 9.5:1 to 9.8:1

That could be compared to Mike Rich's 10.25:1

FBF's 11:1 is probably less than 11:1 if it does not ping like a table tennis player

83820[/snapback]

Hey Dave - no problem here, and no need for an apology! I always find value in exploring things by pitting opposing viewpoints. It's learning, man - not just verbal fisticuffs, eh??

 

Per my post above, I'm sure that that compression ratios are very carefully selected by the engineers. It's obviously far from an arbitrary thing, but there's gotta be much more to it than I can imagine with my relatively limited knowledge of all that must be involved. Far be it from the likes o' me to presume to call their choice a mistake?

 

There were LOTS of what might be considered mistakes made that were prompted by emissions regulations, but you can't entirely fault Guzzi for all of that to my way of thinking - unless you consider things like a shabby ECU map that would pass evidently just because it was so lean, but wouldn't run the motor half as well as a 3-legged dog. Thankfully, most of 'em are still very nicely correctable by the aftermarket and a handfull of really savvy, dedicated, and generous "privateers".

[Skeeve]

Not to miss out on my share of the feeding frenzy I submit the following:

...I take it you're referring to "race porting" - the practice of hogging-out heads with (or more often, without) the benefit of a flow bench for use with larger valves - if that's what you mean by "better quality" valves?

I believe Mike Rich's porting efforts are the only such that have been specifically mentioned, & he's developed (from what I've seen; I'm too poor to be one of his customers... yet!) a gentle hand toward his porting. In other words, he's not into "hogging out" but rather seems focused on actual porting, ie - improving flow velocity.

 

As far as evidence to suggest that larger valves than stock issue wouln't be a "good idea", well - I reckon Pete has access to "evidence" against large-valve heads ... As many builders including Pete have noted (in this thread, as I recall) he doesn't find any advantage - but rather many disadvantages - with use of large-valve heads and extensive porting for engines in either category.

There's a limit to enlarging the valves imposed by having to bury'em deeper in the head. Why do the HiCams make more power? It's not because of a 500rpm higher redline (on the Centauro), but differences in valve area & combustion chamber design; the 4v heads don't have the valves buried in deep pockets at opposite ends of the combustion chamber.

 

  I think those who really know how to port for track and the road mostly just mildly clean 'em up, maybe do light polishing, and slight matching work.  Porting for both road and track seem to be at considerable variance with porting for the dyno.

Prezackly! But the nature of the product that Guzzi seems to have been pushing out the doors [the infamous "Luigi effect" ] and of course *any* manufacturer producing in volume, is that the rough castings see the *least possible* machine- and/or human-intervention.

 

The historical "evidence" against large valves - if you accept the reports from Pete as evidence - has been running pretty strong against 'em - regardless of objectives!  The overall porting quality of the stock heads seems pretty good as is, as I b'leive Pete's often noted so eloquently.  How's that for "evidence"?

 

Well, if you've never gone to the Eurospares site, you should take the time now. Altho' the article there is specific to small-block heads, it reveals just how cr@ppy the stock porting & flow numbers are. With the way things have been going at Guzzi the last couple or three decades, I seriously doubt that this situation has improved significantly.

 

Go to the Edelbrock website & look at their aftermarket heads for the Guzzi counterpart, Harley Davidson, for what *real* ports look like. Hell, look at H-D's own *stock* TC88 heads for what Guzzi should have done to the combustion chamber on the big block heads before the 1st frickin' V7 was ever built! The technology is only 70 years old; admittedly, nobody much bothered with it til the 70s, & even hoary old H-D didn't start making their first teetering steps in that direction until 1984 (over 2 frickin' decades ago!) Dual-plugging? Bah! Added complexity...

 

I think the point Dave was making is that Guzzi needs to incorporate some of this stuff right now into what their pushing; it will stretch "the old ditch-pump" [Roperism] right up to the limit of its capabilities, w/o threatening the long term reliability. (There's some sign that Guzzi is trying; after all, that's what the changes to the Breva mill to increase the rod-ratio are about...) It would very likely push the output (at the piston crown ) right up to that magical double-ought marketing number, & maybe earn them enough street cred to actually sell some of the lovely things! And hey, if they sold enough of them to raise awareness to the point that all the 1000s of road geezs out there who don't own one started to just consider them the next time they went Bike shopping, well, wouldn't that be a wonderful thing?

 

Meanwhile, Guzzi can be working on their NBT, since the handwriting is on the wall for our favorite habit. (& don't think Harley doesn't know their number is up, too; why do you think they're making the VRod? They know that it will be 10 years uphill slogging before The Faithful will accept the water-pumper - that's why they brought it out 5 years ago! Meanwhile, they're teaching the old a/c dog as many new tricks as they can, in order to stretch out it's lifespan. Guzzi needs to follow suit. Actually, Guzzi could do worse than look at everything Harley does & copy it on a much smaller scale. After all, look where H-D was 25 years ago, & where they are now. Guzzi should be so lucky! Not that I'm advocating another brand of biker boutiques.

 

So what's the magic bullet? Will Porting be my ticket to the promised land? No. It'll help with decreasing pinging, by maintaining high intake velocity & improved combustion tho'. Will Hi Compression Pistons be my holy grail? No; but they'll help with improving the fuel efficiency & (everyone @ v11LM's favorite tool - Arr arr arr!) torque. Will Tuneboy take me to the limit? No; but it or a PC3usb (hopefully, someday, with the long-awaited timing module!) can resolve the fueling issues & one is necessary to really take full advantage of any of the foregoing mods.

 

I'm one of the least likely to spend money on high-ticket upgrades of anyone here, but I do believe that a wholistic approach to upgrades will have synergistic f/x, w/o necessarily dooming the motor to a shorter span. In an ideal world, Guzzi would realize it's in their own best interest to provide same straight from the factory; until then, we Guzzisti have to work it out on our own, & by sharing knowledge & perspective, determine just what is the best route forward. Obviously, for some it's better not to mess with it [and believe me, I'm a STRONG proponent of the "If it's not broke, don't fix it!" philosophical school!] & for others, their sense of what's doable, or proper, constrains them to take the standard parts closer to their ideal state.

 

And that's what keeps v11LM such an interesting space!

 

Ride on...

[dlaing]

I don't know how much to trust their engineers.

The Rosso Mandello was supposed to have a superior clutch, but many failed...EDIT only a few allegedly failed...thanks for the correction Jim!

With emissions standards and everything, you would think they might go with higher comp, but maybe higher comp requires a rich mixture at some point.

I do like the slow evolutionary approach that they have taken.

I think the higher compression jump by Guzzi was a good thing, but somehow I trust Mike Rich more, and think the 10.25:1 is a reasonable ratio as long as you re-map properly.

[Mike Stewart]

Hi compression does contribute to higher emissions. More heat = higher engine temps and have alot to do with NOX. I can't remember the results because I gave up my smog license years ago.

 

Going with higher compression will shorten engine life. How much, I don't know . But is is harder on everything from the piston rings to the rod bearings. So that being said, I doubt if you could get the normal 100,000 to 200,000 miles that a normal Guzzi engine would go. But I also doubt the valve stems would last that long anyways.

 

 

 

Mike

 

 

 

 

 

 

Gents!

 

Before we get too much more of a fish "boil" going here, I have a question.  One of you high-comp piston afficionados might enlighten me.

 

Since high-comp pistons wouldn't seem to contribute to any additional emissions (unless sound might be effected enough?), in fact they might actually improve CO and NOX, etc. numbers, and higher compression yields greater burn efficiency, thereby lowering fuel consumption - Why do you suppose mfgr's don't choose to simply install 'em to start with, since they'd be able to claim considerably greater torque and power numbers, as well as top end, 1/4 mile times, etc.?

 

It would ALL seem to be good, even from their perspective - wouldn't it?

 

Enquiring minds just gotta know. 

83819[/snapback]

[dlaing]

snip

83825[/snapback]

Yah, that's what I meant to say

[Skeeve]

Since high-comp pistons wouldn't seem to contribute to any additional emissions (unless sound might be effected enough?), in fact from my understanding, they might actually improve CO and NOX, etc. numbers, and higher compression yields greater burn efficiency, thereby lowering fuel consumption - Why do you suppose mfgr's don't choose to simply install 'em to start with, since they'd be able to claim considerably greater torque and power numbers, as well as top end, 1/4 mile times, etc.?

 

It would ALL seem to be good, even from their perspective - wouldn't it?

83819[/snapback]

 

Higher compression yields higher combustion temps = more NOx. Less CO, so that's good, and now that there're 2-way cats, the reducer stage converts the NOx, so that's all good. And the manufacturers are choosing to install them to start with; why do you think all the sportbikes are up in the 12:1 range, if not higher, now? The problem is is heat, so they're all water-cooled too; the limit to air-cooled motors is about 11:1 with good combustion chamber shape & small diameter pistons; you go to big buckets like Guzzi, Harley & a/c Ducati engines, & you have to back it down to 10:1 or less. (Remember, these are all just rough numbers for comparison's sake...)

 

Back in the 60s, when Harley-Davidson owned Ducati [yes, Virginia: Ducati owes their existence, in a roundabout way, to H-D's custodianship...] or rather, the company that was to become Ducati, they ran these little 250 & 350cc lay-down single 4strokes & won a bunch of races. I forget who the author was, Gordon Jennings or who, but it mentioned how back then, they'd cranked the compression up as high as they could, but due to the oddball combustion chamber design [oddball now; quite normal back then], the piston wound up looking like a camel's back: two high humps, which forced the mixture into the valve pockets, and then they had to cut a channel thru all this to connect the spark plug to the fuel! There's a theoretical limit (15:1 for gas engines, iirc, before you start verging into the diesel realm) and a practical limit (about 11:1, I think he said it was in the old Aermacchis...) to everything.

[jrt]

I'd love to see someone offer a roller valve kit...perhaps that would minimize valve stem wear.

83729[/snapback]

 

 

I actually looked into this- really, really hard- for awhile. I was prepared to shell out some bucks, too. The people I talked with (MGCycles, Manfred Hecht) told me that the roller rockers tended to break. Too bad. I had a chance to ride a V7 sport built up by Manfred that was totally tricked out- roller rockers, roller bearing mains, everything balanced. It was a completely different feel than any other Guzzi I've ever ridden. Like a BMW...uh..no, better than that, but really tight.

Not to say you CAN'T make a set. It just wasn't feasible at the time. I would still love to find someone who would make them. Then I could buy a set....For my G5.

 

 

Edit: btw, when I took my G6 apart for it's too-long-in-the-making rebuild, I did have to replace the cam followers and the pushrods, but the (stock) cam was just fine. This is after close to 300K miles. Dunno what that says about valve train wear in the V11, but I do realize that the G5 is not a high performance motor.

[Guest ratchethack]

Mike and Skeeve, you've enlightened me considerably. Many thanks!

 

So one "viable" argument (if'n y'er like me, y'er none to squeamish about thwarting the enviro-Nazi's wherever they stick their greasy little paws) for replacing stock pistons with hi-comps could ostensibly be that - emissions restrictions be damned - Let's go for that POWER and TORQUE.

 

On the other hand, as previously mentioned, we have increased operating temps and a general harder-hammering of essentially every moving part of the drivetrain, starting with the piston itself, rings, and right on down the line...and the associated shorter expected lifespan of all involved...

 

Trade-offs will be trade-offs, n'est-ce pas?

[Greg Field]

Ducati was a separate company and making motorcycles while H-D owned Aermacchi. Aermacchi later became Cagiva, but H-D never owned Ducati and had nothing to do with the company's existence.

 

H-D almost bought Moto Morini and even looked at buying Moto Guzzi, but so far as I know never even looked at Ducati.

[helicopterjim R.I.P.]

The Rosso Mandello was supposed to have a superior clutch, but many failed...

 

83826[/snapback]

 

Where did you hear that? I have not yet heard of Rosso Mandello clutch failing.

[pete roper]

Oh Boy! A lot of traffic on this subject since I went out this morning!

 

There are lots of issues raised that need addressing and I'll try to give my opinions on all of them if I can over the next couple of days BUT. Two things.

 

1.) I want to keep this amicable. If anyone starts setting themselves up as an oracle it makes the whole discussion pointless. We should all remember that.

 

2.) The original V7 produced 35 BHP. The latest V11/Breva variants produce *roughly* 80bhp. Although the engine has increased in capacity by about 80% the essential architechture remains the same. That equates to a major increase of HP for capacity. You don't get that without trade-offs, no matter how much materials may of *Improved* over the years.

 

Mike Rich's 10.25 to 1 static looks a lot more feasible to me as a worthwhile opinion with pump gas than 11 to 1. Add in the fact that Mr Rich seems to actually LIKE Guzzis and care I'd suggest that his pistons along with decent porting mods will probably offer the 10% improvement with few downsides that so many people crave but longevity WILL suffer. It has to. That is dictated by the laws of physics so unless you are one of those barking mad fanatics who believes that God has given you a 'Note from Mum' that allows you to bend the laws of the natural world you're limited to the same parameters that the rest of us poor mortals are, and that means that if it makes *more* of anything it will wear out faster. Whether you accept that wearing out as acceptable or not is obviously very subjective but it will happen. I'm not saying that getting 10% more power will lessen your engine life by 10%, in fact depending on a lot of factors it may be a lot less, or a lot more, but there will be a trade off.

 

Anyway, I've been standing in the sun all day talking bollocks about Guzzis. I've come home, I've got a beer on the go and I'm going to sit and relax and NOT think about motorbikes for a few hours

 

Pete

[dlaing]

Where did you hear that? I have not yet heard of  Rosso Mandello clutch failing.

83841[/snapback]

Sorry faulty memory.

Only a few failed.

A google of this forum indicated only some from the Italian forum had failures.

I suppose I must have associated the Rosso Mandello clutch with the Scura clutch....

Sorry RM owners!

[pete roper]

Correction. I orignally said the engine capacity had increased 80%. This is, because, as my daughter has so eloquently pointed out, I'm stupid . 700 to 1064 is about 28% (roughly!) but the power has doubled. This makes my crazed rantings a bit more inteligable I hope. I'm off to bed. N'Night!

 

Pete. (Hard day at the office dear?)

[helicopterjim R.I.P.]

Sorry faulty memory.

Only a few failed.

A google of this forum indicated only some from the Italian forum had failures.

I suppose I must have associated the Rosso Mandello clutch with the Scura clutch....

Sorry RM owners!

83851[/snapback]

 

We Rosso Mandello guys don't like to be tarred with the same brush as those Scura Hut guys, ya know!! We got our own tar brush!!!

 

No worries!

Jim

[Greg Field]

Pete:

 

An increase from 700 to 1064 is an increase of 52 percent. Tell her that she's a chip off the ol' block.