Engine Rod Length

[luhbo]

Does anyone know the length of a Breva rod? Are the 1200 2V rods even longer? How long are those? Or are they all the same as the V11 rods, 140 mm?

 

Thx, Hubert

[pete roper]

Does anyone know the length of a Breva rod? Are the 1200 2V rods even longer? How long are those? Or are they all the same as the V11 rods, 140 mm?

 

Thx, Hubert

 

Pretty certain all the 2V CARC bike engines with the exception of the 850's and the Bellagio are the same Hubert but I'll double check for you when I get the chance. The 1100 and 1200 rods are identical I believe. Capacity increase is bore alone. In NZ at the moment on hols.

 

Pete

[luhbo]

Thank you Pete. What I've heard the newer engines (Breva and up) had shorter pistons and longer rods, alas the new shop manuals don't show any details for the rods besides the bearings (don't think a rod has ever been stretched anyway).

As the question actually is put more or less out of curiosity don't put too much effort into this.

 

THX, Hubert

[pete roper]

Thank you Pete. What I've heard the newer engines (Breva and up) had shorter pistons and longer rods, alas the new shop manuals don't show any details for the rods besides the bearings (don't think a rod has ever been stretched anyway).

As the question actually is put more or less out of curiosity don't put too much effort into this.

 

THX, Hubert

 

Yup, definitely. The distance from the grudge on to the deck of the piston is shorter and I *think* that although the bore remained the same the stoke may of been lengthened but I may of got that wrong. Certainly on the 1100's/1200's the rods are several mm longer than on the V11's and other 1068 motors.

 

Pete

[Skeeve]

Thank you Pete. What I've heard the newer engines (Breva and up) had shorter pistons and longer rods, alas the new shop manuals don't show any details for the rods besides the bearings (don't think a rod has ever been stretched anyway).

As the question actually is put more or less out of curiosity don't put too much effort into this.

 

THX, Hubert

 

Yup, definitely. The distance from the grudge on to the deck of the piston is shorter and I *think* that although the bore remained the same the stoke may of been lengthened but I may of got that wrong. Certainly on the 1100's/1200's the rods are several mm longer than on the V11's and other 1068 motors.

 

Pete

 

When Guzzi announced the updated 2v in the Breva, one of the claims was that it had a revised (improved) rod ratio. Nice to have someone w/ 1st hand experience confirming the rod lengths and piston deck heights are different... The irony being, of course, that the V11 motor was fitted with a cam that would have benefited more from the high rpm properties of a better rod ratio than the one that came in the Breva/Griso mills [softened for later smog regs.]

[luhbo]

... the rod lengths and piston deck heights are different...

 

Any numbers, maybe?

Other then the rod length the timing figures are still available in the new manuals, and, as usual one might say, those figures are still the same.

 

Hubert

[Skeeve]

...the timing figures are still available in the new manuals, and... those figures are still the same.

 

 

Well, yes,they would be, since a slight improvement to the rod ratio isn't going to affect the valve or ignition timing; this isn't a 2smoke, after all!

 

Sorry, I wish I had numbers, I just remember reading the text that went with the nifty cutaway engine fotos of the new square sump engine when the Brevona was announced. That the factory had improved the rod ratio was about all that was said; more attention was paid to the dual-plugged heads [which admittedly, is a more noticeable change than some slightly improved high-rpm power characteristics on an engine w/ a milder cam than the previous generation V11 motor, and moreover wasn't known for turning high rpm to begin with...] It's probably mentioned in Guzziology, but my older edition is in a box somewhere [i've been moving] and I haven't plunked down for the latest ed. of G'ogy 'cause I'm too poor at the moment. I'm very interested in what's listed for the Nuovo HiCam motors, as the newest ed. of G'ogy is supposed to cover them, but since I don't own one [yet] and have no immediate prospects of doing so, my older ed. will still serve my needs [when I unbox it again.]

[Lucky Phil]

...the timing figures are still available in the new manuals, and... those figures are still the same.

 

 

Well, yes,they would be, since a slight improvement to the rod ratio isn't going to affect the valve or ignition timing; this isn't a 2smoke, after all!

 

 

Well if you want to be really picky about it then Rod ratio will have a slight effect on what the ignition timing profile is. Rod ratio has an impact on the pistons "dwell time" at TDC and therefore the ignition curve required.

Ciao