Author Topic: New crankshaft/connecting rod design for 2021 V7/V9  (Read 3875 times)

Offline DaSwami

  • Guzzi Hero
  • *****
  • Posts: 502
  • Location: NW Florida via Montana
New crankshaft/connecting rod design for 2021 V7/V9
« on: January 31, 2021, 11:01:20 PM »
Does this Cycleworld comment raise an eyebrow with anyone?

"An unexpected and fairly radical technical modification separating the V7/V9 V-twin engine from all previous editions, and from the V85 TT, is that the crankshaft here is of the press-fit type, with one-piece con-rods turning on plain bearings, rather than a forged one-piece unit. This follows the same engineering approach used on all Piaggio four-stroke scooter singles. Reducing production cost is the ultimate reason for the change. The more powerful, higher-revving V85 TT retains its solid forged crankshaft and cap-type rod."



Offline lucky phil

  • Guzzi Hero
  • *****
  • Posts: 1397
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #1 on: February 01, 2021, 12:18:47 AM »
Does this Cycleworld comment raise an eyebrow with anyone?

"An unexpected and fairly radical technical modification separating the V7/V9 V-twin engine from all previous editions, and from the V85 TT, is that the crankshaft here is of the press-fit type, with one-piece con-rods turning on plain bearings, rather than a forged one-piece unit. This follows the same engineering approach used on all Piaggio four-stroke scooter singles. Reducing production cost is the ultimate reason for the change. The more powerful, higher-revving V85 TT retains its solid forged crankshaft and cap-type rod."

Just like a roller big end but different. Doesn't sound appealing although if its bullet proof should be ok. Nobody's going to be rebuilding engines in 15 years time.

Ciao
If you're not living on the edge you're taking up to much room.

Offline kirby1923

  • Guzzi Mentor
  • ****
  • *
  • *
  • Posts: 459
  • '81 CX100
  • Location: SoCal (rural) near Tehachapi CA, Rogers AR when in the states other times GMT+1 thu +6
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #2 on: February 01, 2021, 07:57:23 AM »
Harley has been using press together cranks form its beginnings  to this day (on the big twins).
« Last Edit: February 01, 2021, 08:18:27 AM by kirby1923 »
'81 CX100


A calm and modest life brings more happiness than the constant pursuit of success combined with constant restlessness.. Einstein,A

Offline moto-uno

  • Guzzi Hero
  • *****
  • Posts: 889
  • Location: Burnaby , B.C
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #3 on: February 01, 2021, 08:03:43 AM »
^ No they were  not ! Press fit cranks on Harleys didn't start until the Twin cam model ( FWIW) . The Laverda triples had press fit
cranks and were fairly durable . Not to forget most 2 strokes were also pressed together cranks !

Wildgoose Chase Moto Guzzi

Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #3 on: February 01, 2021, 08:03:43 AM »

Offline acguzzi

  • Guzzi Mentor
  • ****
  • Posts: 270
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #4 on: February 01, 2021, 08:19:29 AM »
well there is the reason for not using the v9 engine in a performance twin.

Offline Tusayan

  • Guzzi Hero
  • *****
  • Posts: 1511
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #5 on: February 01, 2021, 09:29:48 AM »
The biggest benefit of the industry moving away from roller bearing bottom ends in the 70s and before was the elimination of pressed together crankshafts.  Itís an archaic concept that only survived as long as it did due to concerns about reliable oiling of plain bearings that themselves should should have been put aside in the 1940s or before.  Just because Piaggio has equipment to make built up crankshafts for scooters and apparently cuts cost of production using them does not make pressed together multi-piece crankshafts a good thing for the owner of a Guzzi.

Offline kirby1923

  • Guzzi Mentor
  • ****
  • *
  • *
  • Posts: 459
  • '81 CX100
  • Location: SoCal (rural) near Tehachapi CA, Rogers AR when in the states other times GMT+1 thu +6
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #6 on: February 01, 2021, 09:57:00 AM »
Yes I agree very obsolescence in an engineering sense. Controlling run out during the manufacturing process is difficult, and HD keeps upping the tolerance.

A better way would be a one piece crank forging with an articulated  rod like a radial aircraft engine.
'81 CX100


A calm and modest life brings more happiness than the constant pursuit of success combined with constant restlessness.. Einstein,A

Offline huub

  • Guzzi Hero
  • *****
  • Posts: 621
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #7 on: February 01, 2021, 11:36:09 AM »
Should make rebuilding a engine easier !
for current smallblocks no oversize bearings are available so any wear means a scrap crankshaft.
With a pressed up crankshaft guzzi might actually provide the crankpin, making the crankshaft rebuildable.

Offline acguzzi

  • Guzzi Mentor
  • ****
  • Posts: 270
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #8 on: February 01, 2021, 12:21:49 PM »
also means you can't replace or inspect big ends without disassembling the crank

Offline Bulldog9

  • Guzzi Hero
  • *****
  • *
  • *
  • *
  • Posts: 1695
  • Location: United States
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #9 on: February 01, 2021, 02:28:53 PM »
I'd like to see pics of this, having a hard time picturing. I've never had a Guzzi motor apart, closest look I've had was when I dropped the pan on the Convert to change the oil filter Was surprised to not see a windage tray or much to keep oil from schloshing onto the crank.
The Living: 1976 Convert, 2007 GRiSO, 2016 Stornello #742, 2008 1200 Sport
The Departed: 2017 MGX, 2014 Norge GT,  In Stasis: 1978 XS750, XS1100SF (134K miles and going)

Offline jwinwi

  • Guzzi Hero
  • *****
  • *
  • *
  • *
  • Posts: 733
  • Acta Non Verba
  • Location: Wisconsin
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #10 on: February 01, 2021, 02:56:05 PM »
Carlo Guzzi and Lino Tonti are rolling over in their graves... :cry:
« Last Edit: February 01, 2021, 03:07:19 PM by jwinwi »
96 Blue Sport 1100 'Stella'
76 V1000 Ex Convert
73 V7 Sport
02 Suzuki SV650 AHRMA #646 SoT3

 'The days I keep my gratitude higher than my expectations I have really good days'. RWH

oldbike54

  • Guest
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #11 on: February 01, 2021, 03:20:43 PM »
 Should help with dial indicator and large hide mallet sales .

 Dusty

Offline lucky phil

  • Guzzi Hero
  • *****
  • Posts: 1397
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #12 on: February 01, 2021, 04:23:44 PM »
Harley has been using press together cranks form its beginnings  to this day (on the big twins).

And thats a recommendation?

Ciao
If you're not living on the edge you're taking up to much room.

Offline lucky phil

  • Guzzi Hero
  • *****
  • Posts: 1397
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #13 on: February 01, 2021, 04:35:31 PM »
The biggest benefit of the industry moving away from roller bearing bottom ends in the 70s and before was the elimination of pressed together crankshafts.  Itís an archaic concept that only survived as long as it did due to concerns about reliable oiling of plain bearings that themselves should should have been put aside in the 1940s or before.  Just because Piaggio has equipment to make built up crankshafts for scooters and apparently cuts cost of production using them does not make pressed together multi-piece crankshafts a good thing for the owner of a Guzzi.

Yep all true but 99% of todays buyers wont understand and will never need to. More interested in connectivity than engineering. I personally hate the way modern engines are designed around cheapness to manufacture and fast assembly on a production line, makes insitu maintenance very difficult. Both my cars as do many other engines now utilise friction drive for the OHC's so no keyed crank or camshafts. If you loosen off the front pulley bolt to remove it for a seal replacement for instance then its re do the valve timing which isn't as easy as it sounds with the dismantling of half the top end to fit the timing tools and removing accessories like the HP fuel pump and vacuum pump. Painful and many amatures have been caught out by this alone.

Ciao  e
If you're not living on the edge you're taking up to much room.

Offline LowRyter

  • Guzzi Hero
  • *****
  • *
  • *
  • *
  • *
  • Posts: 15260
  • Location: Edmond OK
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #14 on: February 01, 2021, 04:40:30 PM »
Wait, I always thought that pressed cranks were quite a bit more labor intensive and expensive to build.  This is the first time I've ever read the opposite.   I don't know why two piece rods could be revved at higher RPMs and more stress than one piece rods; if there is a difference, I'd think would be the other way around. 

OK, since I'm the least mechanically inclined person on the Board, someone please educate me.

Thanks. 
« Last Edit: February 01, 2021, 04:48:18 PM by LowRyter »
John L 
When life gets you down remember it's one down and the rest are up.  (1-N-23456)

Offline kirby1923

  • Guzzi Mentor
  • ****
  • *
  • *
  • Posts: 459
  • '81 CX100
  • Location: SoCal (rural) near Tehachapi CA, Rogers AR when in the states other times GMT+1 thu +6
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #15 on: February 01, 2021, 04:41:47 PM »
And thats a recommendation?

Ciao


In a word no.
'81 CX100


A calm and modest life brings more happiness than the constant pursuit of success combined with constant restlessness.. Einstein,A

Offline LowRyter

  • Guzzi Hero
  • *****
  • *
  • *
  • *
  • *
  • Posts: 15260
  • Location: Edmond OK
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #16 on: February 01, 2021, 04:46:05 PM »
^ No they were  not ! Press fit cranks on Harleys didn't start until the Twin cam model ( FWIW) . The Laverda triples had press fit
cranks and were fairly durable . Not to forget most 2 strokes were also pressed together cranks !

I thought all Harleys had press fit cranks. 

Isn't that how they installed those "knife and fork" rods? 
John L 
When life gets you down remember it's one down and the rest are up.  (1-N-23456)

Offline lucky phil

  • Guzzi Hero
  • *****
  • Posts: 1397
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #17 on: February 01, 2021, 04:51:13 PM »
I thought all Harleys had press fit cranks. 

Isn't that how they installed those "knife and fork" rods?

Like older British bikes some were a tapered pin with a nut to hold in place from memory.
The side by side rods on a common pin like a Ducati has is the best option unless crank width/length is an issue. Articulated rods in all there forms whether a "master rod" situation or a forked arrangement like a Merlin engine uses are less desirable and generally for low rpm applications only.

Ciao
« Last Edit: February 01, 2021, 04:55:12 PM by lucky phil »
If you're not living on the edge you're taking up to much room.

Offline kirby1923

  • Guzzi Mentor
  • ****
  • *
  • *
  • Posts: 459
  • '81 CX100
  • Location: SoCal (rural) near Tehachapi CA, Rogers AR when in the states other times GMT+1 thu +6
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #18 on: February 01, 2021, 04:58:22 PM »
Wait, I always thought that pressed cranks were quite bit more labor intensive and expensive to build.  This is the first time I've ever read the opposite.   I don't know why two piece rods could be revved at higher RPMs and more stress than one piece rods; if there is a difference, I'd think would be the other way around. 

OK, since I'm the least mechanically inclined person on the Board, someone please educate me.

Thanks.

The factory (HD) does not sell parts for the crank but you can pull them apart and put them back together in your shop if you have the right equipment, Most of the people that do this send them to someone (only one place really) and they will refresh the crank, balance and weld the pin up if requested.

The rods are blade and fork. You can get away with a bit more RPM 'cause w/the blade and fork rod (
s) there is no offset of the cylinders thus no shaking order side to side like a Guzzi twin of a BMW.

The first press together crank from the factory was the XR, then  later the twin cam (which I used to always call the big twin)

If they, HD machines, are not too abused with big after market cylinders and other hop up stuff they do OK more or less. For me the 45 deg cylinders are only good for the unique sound and produce surprisingly good traction, much like a big single.

Still a bad way to do it in my opinion.
« Last Edit: February 01, 2021, 05:01:38 PM by kirby1923 »
'81 CX100


A calm and modest life brings more happiness than the constant pursuit of success combined with constant restlessness.. Einstein,A

Offline Tusayan

  • Guzzi Hero
  • *****
  • Posts: 1511
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #19 on: February 01, 2021, 07:45:24 PM »
I always thought that pressed cranks were quite a bit more labor intensive and expensive to build.  This is the first time I've ever read the opposite.   I don't know why two piece rods could be revved at higher RPMs and more stress than one piece rods; if there is a difference, I'd think would be the other way around. 

OK, since I'm the least mechanically inclined person on the Board, someone please educate me.

Pressed together cranks with roller bearing rods, assembled by hand are more expensive to build.  Apparently pressed together single throw V-twin cranks with simple one piece rods/bearings assembled on the same machine that does the same for single single scooter engines is cheaper, or so believes Piaggio.

One piece rods may well be stronger and better for high RPM, when fitted with a plain bearing as in this case.  But it imposes a burden on anybody who ever has to work on the engine, and this engine doesnít rev high enough for it to matter, or close, because pushrods prevent high RPM.

Itís just a cost saving thing, squeezing pennies out of something in exchange for reducing its practical lifespan.  Fine for the first buyer who likely never knows, fine for Piaggio because there wonít be as many multi-resale used bikes for them to compete with in selling new bikes.  Not so good for anybody who thinks long life is a measure of quality.
« Last Edit: February 01, 2021, 07:55:10 PM by Tusayan »

Offline LowRyter

  • Guzzi Hero
  • *****
  • *
  • *
  • *
  • *
  • Posts: 15260
  • Location: Edmond OK
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #20 on: February 01, 2021, 08:26:36 PM »
thanks for the replies, more confused than even.    :shocked:

are Harley cranks solid or pressed?  are pressed cranks really cheaper?  how would one piece rods fit on a solid crank? 

still confused.

don't worry about answering because I probably won't understand.   :sad:
« Last Edit: February 01, 2021, 08:31:55 PM by LowRyter »
John L 
When life gets you down remember it's one down and the rest are up.  (1-N-23456)

Offline moto-uno

  • Guzzi Hero
  • *****
  • Posts: 889
  • Location: Burnaby , B.C
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #21 on: February 01, 2021, 08:28:11 PM »
Keep in mind when making references to HD , they sell more bikes with pressed together cranks in a couple of months than Guzzi does in a decade  :popcorn:.
I worked on them at dealerships for decades and of course went to their factory for specialty training , so kinda familiar with them . And owned and ridden
Guzzi's for 38 years . I definitely prefer my Guzzi's , but that doesn't make H-D's bad bikes , just not my style ( and my pockets aren't that deep either :) ).
Peter

Offline DaSwami

  • Guzzi Hero
  • *****
  • Posts: 502
  • Location: NW Florida via Montana
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #22 on: February 01, 2021, 09:58:22 PM »

Itís just a cost saving thing, squeezing pennies out of something in exchange for reducing its practical lifespan.  Fine for the first buyer who likely never knows, fine for Piaggio because there wonít be as many multi-resale used bikes for them to compete with in selling new bikes.  Not so good for anybody who thinks long life is a measure of quality.

This was my initial thought, that this move may save them a few $$ at the cost of a more robust unit longterm.  Glad I have my V7III's.

However, I know just enough to be dangerous.

Most interesting to me, was that Cycleworld even bothered to mention it.  Seems like a detail that could just as well be left unsaid with no skin off their nose.


Offline voncrump

  • Guzzi Mentor
  • ****
  • Posts: 366
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #23 on: February 02, 2021, 12:24:35 AM »
The way I see it is;
If the crank pin is the same size then it should be as strong as the existing big end.
It will allow them to use very hard material in the pin.
The rods will be lighter thus allowing a better balance situation.
If the big ends fail in either type (seems to be very rare on modern V7s) then the crank has to be removed, repaired if possible or replaced.
What is the problem?
As long as the the crank doesnít slip in the press fit all will be as normal.
Plus they are still making the V85 in the normal way so they could use that bottom end in the long awaited V85 Lemans.
Maybe even have another try at 4V per cylinder as some people have suggested might happen after they looked at the
Castings on the hemi motors.
Cheers, voncrump
1996 1100 sport
2016 V711
1988  Lario ( long gone )
1982 V50111 (long gone)

Offline Murray

  • Guzzi Hero
  • *****
  • Posts: 2915
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #24 on: February 02, 2021, 12:35:28 AM »
The question are the fittings a Hirth sp? style firrting similar used on old Porseche's and eventually the V8 gp racer or are they some dodgy tappered fitting i'm thinking the latter.

Offline Rough Edge racing

  • Guzzi Hero
  • *****
  • Posts: 4392
  • Location: North of Finger Lakes
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #25 on: February 02, 2021, 05:37:08 AM »
Like older British bikes some were a tapered pin with a nut to hold in place from memory.
The side by side rods on a common pin like a Ducati has is the best option unless crank width/length is an issue. Articulated rods in all there forms whether a "master rod" situation or a forked arrangement like a Merlin engine uses are less desirable and generally for low rpm applications only.

Ciao
Yes, the large threaded nut provides the "press" onto the tapered joint.....Kawasaki 900 was a multi piece crank along with a few other Japanese 4 strokes..I believe they were pressed..
 WW2 Merlin and Allison used  knife and fork bolted rods with a one piece crank . The Dailmer Benz used both side by side and knife and fork with one piece cranks...
  When Allison dominated unlimited hydro plane racing the 1710 cube engines crowded 4500  rpm and made over 4000 hp...
96 Ducati 900M , 79 Triumph 750,61 BSA A10, 650 Triumph land speed racer , dual 650 Triumph engine land speed racer.
" I  don't know what the world may need
But a V8 engine is a good start for me
Think I'll drive to find a place, to be surly"

Online twowheeladdict

  • Guzzi Hero
  • *****
  • Posts: 4085
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #26 on: February 02, 2021, 06:37:29 AM »
So, I've read a lot of opinions here.

What are the real world consequences of this design change? 

The engine will last less miles?

The new crankshaft will now be the first point of failure?

Does any of this matter to someone who might put 2000 miles a year average on a small block? 

What percentage of motorcycles, other than touring models, ever see 80,000 miles? 

How many 1998 - 2003 bikes have we seen on this forum recently purchased with under 35,000 miles on them?

Maybe we need a survey for just Moto Guzzis on this forum with Year, Model, Mileage so we know if this design change will have real world affects on future Guzzi riders. 

2018 V7 III Carbon Dark #0009 of 1921
2018 Road Glide Special
2019 Royal Enfield Himalayan
2017 Suzuki Van Van 200

Offline Chuck in Indiana

  • Guzzi Hero
  • *****
  • *
  • *
  • *
  • *
  • *
  • Posts: 28327
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #27 on: February 02, 2021, 06:52:22 AM »
Much ado about not much, as far as I'm concerned.  :smiley: I've never managed to wear out a motorcycle engine yet..
Chuck in (Elwood) Indiana/sometimes SoCal

02 Scura RC
87 AeroLario
79 G5
95 Skorpion tour
 
I think senility is going to be a fairly smooth transition for me..

Offline Aaron D.

  • Guzzi Hero
  • *****
  • Posts: 5843
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #28 on: February 02, 2021, 07:00:13 AM »
Crazy panic time!

Thinking of all the older sports and racing cars with built-up cranks.  Not to mention my Laverda triple.

Like Chuck I have never worn out an engine. I suspect this will be a big savings for Piaggio.

To help with the angst, I should point out that you can't buy main bearing inserts for Vespa engines-they are sold as part of the case.

Offline jwinwi

  • Guzzi Hero
  • *****
  • *
  • *
  • *
  • Posts: 733
  • Acta Non Verba
  • Location: Wisconsin
Re: New crankshaft/connecting rod design for 2021 V7/V9
« Reply #29 on: February 02, 2021, 07:58:48 AM »
Crazy panic time!

Thinking of all the older sports and racing cars with built-up cranks.  Not to mention my Laverda triple.

Like Chuck I have never worn out an engine. I suspect this will be a big savings for Piaggio.

To help with the angst, I should point out that you can't buy main bearing inserts for Vespa engines-they are sold as part of the case.

Um, no. Just another example of how the cheapest solution is the way Guzzi is run now. If the pressed together crank is a better solution, why are they still using the forged crank on the V85?
96 Blue Sport 1100 'Stella'
76 V1000 Ex Convert
73 V7 Sport
02 Suzuki SV650 AHRMA #646 SoT3

 'The days I keep my gratitude higher than my expectations I have really good days'. RWH


Harper's Moto Guzzi
Harper's Moto Guzzi. Where we still answer the phone, use the highest quality parts, and also do Transmission, rear drive, and carb rebuilds fast. Call us at 816.697.3411 and get your problems resolved.
http://www.harpermoto.com
Advertise Here
 

***Wildguzzi Official Logo High Quality 5 Color Window Decals Back In Stock***
Shipping in USA Only. Awesome quality. Back by popular demand. All proceeds go back into the forum.
http://www.wildguzzi.com/Products/products.htm
Advertise Here