ScuRoo

I’ll follow with interest. Your enthusiasm & skills in fettling V11’s are fantastically admirable Scud - & your advocacy on drilling cush rubbers is intriguing. I remember reading Greg’s original post many, many years ago - with benefits of the drive being made cushier! So refreshing myself again on the cush subject, various posts stood out... MartyNZ, “I agree with him that the V11 is improved, and the drive train should last longer, with a cushier cush drive. But I don't share his view that engine braking causes damage to the wheel drive spline. I think that each 530cc piston slamming torque down the drive train every engine rev is the main reason for spline wear.” Jim in NZ, “The original design was OK, but the rubbers are very hard. I didn't drill mine, but I took out every alternate rubber wedge. I also regularly clean the whole cush drive and grease the centre bearing every 10,000km service. The advantage is that you can feel that the cush drive is a bit softer every time you change gear, with less abrupt take-up of the power. This must (by my reasoning) be kinder to the entire drive train fromgearbox to tyres.” LowRyter, “OK, the idea of drilling the cush rubber is to take shock out of the driveline for the purpose of a smoother ride or preventing driveline failure.” docc, “Seems the idea is all about cushioning the drive line.” Jim in NZ, “Yep, the idea is about cushioning the drive line, and I'm sure it will reduce stresses on all components during hard acceleration, wheelies, clutchless gear changes, unintentionally jiggling the throttle as you go over a bumpy road, and so on.“ LuckyPhil, “I dont really like the idea of removing rubbers because it means that the torque is now transmitted through only half the metal drive blades” Etc., etc. Now having read all that on the benefits of cushioning the drivetrain & even LP’s concern on torque being transmitted... If this all makes so much sense - where is the logic in then increasing “slamming torque down the valve train every engine rev” through to the drive splines - & with torque backlash directly transmitted back again by the very installation of direct drive timing gears? Isn’t this a tad oxymoronic - anyone else see the dichotomy here? I’m left scratching my head over all this... WTH - does this mean drive splines are more delicate than the cam/ drive train?

"Okay, Houston... we've had a problem here.” https://www.abc.net.au/science/k2/moments/gmis9906.htm Your US model V11 didn’t come with the O2 sensor p6x - which creates the closed-loop feedback to the ECU refining the STFT & LTFT functions. As Mr Cameron pointed out, “If there is an oxygen sensor in the exhaust system, it detects any deviation from the desired mixture and the ECU corrects it.” The Italian’s discovered the MG oem sensor was flawed (as did Fiat). Only relevant for those V11’s 15RC O2 equipped - swapping the sensor unleashes the ECU to perform optimally. Good luck with tyre!

Ha! Boxing Day temp downunder... funny thing is we still give each other Xmas cards portraying Santa snow scenes! 🤤

For all those late model V11’s (15RC ECU with oem O2 sensor) improving/ maximising your bikes O2 signalling speed pays dividends. Mr Cameron’s recent article expands on how fast modern ECU’s can be... “Digital fuel injection is like having your own highly experienced professional race tuner constantly optimizing the operation of your engine. If it seems impossible that so much computation can keep up with a 12,000-rpm engine, consider that the clock speed of some modern ECUs is 40 mHz; that is, the computer moves through 40 million switching states per second. Remember, too, that the speed of electronic signals is high and the dimensions of a computer chip are tiny. One revolution of a motorcycle crankshaft turning at 12,000 rpm takes 60/12,000 = .005 second, so during one turn of the crank the ECU can perform 200,000 clock cycles. Digital is fast.“ Simply upgrading to the LSH24 unleashes the 15RC ECU from the limiting LSH15 faulty (slow) sensor speed & is paramount to installing a modern ECU & rebooting the refinement level to a hiccup free silky smooth 100%. 👍😋 https://www.cycleworld.com/story/blogs/ask-kevin/motorcycle-carburetor-and-fuel-injection-explained/?utm_source=sendinblue&utm_campaign=CYW Sunday Best 122621&utm_medium=email

Yep true... bikes for real mountain men. Men who like mountin’ women!

Well said Twin AH Riding my V11 Scura R is even more fun... because cruising V11Lemans learning up on all the helpful tidbits about V11’s just adds to it! Merry Christmas Guzzisti!

Haha... chortle! You really have missed your natural vocation - you probably would’ve made a half decent stand-up!

Great stuff fella’s! Enjoyed researching this topic. This gear opportunity has been fascinating in gaining a greater understanding of ignition camshaft drives - there’s a helluva lot more involved I had no real appreciation for to such a granular degree. Learning new understandings on concepts which seem, as Docc puts it, “non-intuitive” can be quite humbling! Like for example, I’ll never be quite so unthinking of my RPM’s as just some simplistic spinning speed ever again! “Periodic combustion impulses result in rotational speed fluctuations of the crankshaft. Ignition and combustion within a cylinder cause a rapid rise in gas pressure and an angular acceleration of the crankshaft. Gas compression in the next cylinder causes immediate deceleration. Torque pulsations result in crankshaft torsional vibrations which reach the camshaft(s) and auxiliaries via belt or chain drives.” https://www.rotec-munich.de/wp-content/uploads/2019/12/torsional-vibration-measurement.pdf As usual, Mr Cameron always offers a compelling motorcycling perspective. https://www.cycleworld.com/story/bikes/about-motorcycle-engine-cam-drive-systems/ It’s Christmas Eve & the missus has got some concert playing on the box - so Merry Christmas!

Wow! Scud that’s excellent - you’ll be able to subjectively compare your findings each step from OEM tensioner —> Valtek improve —> Gears impact That’s a great opportunity for a step by step comparison if you wish. In the interests of backyard garage ‘scientific investigations’ maybe consider logging your findings on the Valtek improvement more comprehensively here prior to eventual gear install - so your opinions on the OEM —> Valtek can always be future viewed as unadulterated in relation to your eventual gear findings. Now with respect to the F1 vid I’ve been contemplating the relative effects of TDC -> mid-stroke = fast Mid-stroke -> BDC = slow Presumably with the camshaft turning at half speed to crank speed there’s somewhat of a ‘muffling’ or ‘dampening’ effect to the cam just by the very nature of effectively turning at half the crank speed. Would that be true? Also, as gears provide direct connection the timing is immovably more accurate, right? Now, with chains I’m presuming the chain ‘absorbs’ at minimum the mathematical difference between the TDC->mid-stroke fast & the mid-stroke->BDC slow? I hope I’ve explained that adequately... so far! So... with the high rate of varying our speeds up & down accelerating & decelerating chains effect the accuracy of the ignition event by an amount somewhere along & within the range of the TDC to BDC speed differentials? Whew! #@$&@#@ if I can collect my thoughts & try to relate that again... Am I on the right track here? I’m sure there’s more to it but in general terms... Trying to visualise what those actual conceptual differences are between chain & gears.

That’s some surprisingly illustrious company there that Guzzi isn’t usually compared with tech wise... “Whatcha talkin’ bout Willis?” 🧐 Can you expand on that a bit more please LP?

Harmonic vibrations... Had no visual comprehension on how an engine created these - I guess I just kinda assumed it was produced by the combustion bangs💥 ...turns out it’s more related to the stroke travel speed differentials! Amazing F1 in-depth explanation in 1st half of this vid (the 2nd half is pure tech-sex!) just learned me! But... it’s in the noggin’ now!

Got into a chat with a specialist LS V8 performance engine builder at our local Italian mercato the other day... I mentioned timing gears & he wasn’t a fan. He liked chains, specifically... Cloyes. Wasn’t a fan of the added gear vibration. His answer surprised the heck outta me! So later on I started googling “timing gears” & “vibration”... seems it can occur. Gear noise = vibration + heat Fomo is strong in me... must ugh, resist! 🍿😋

...should be handy for those short-arsed early adopters deciding ...er, among us 🤭

...try this link 👍

Yunupingu was born as Tom Djambayang Bakamana Yunupingu on 17 September 1956 in Yirrkala in Arnhem Land, an Aboriginal reserve in the northeastern part of the Northern Territory. He was a member of the Gumatj people, one of sixteen groups of the Yolngu people. His skin name was Gudjuk, but his name was changed to Mandawuy in 1990 when a family member with the same name died, in line with Yolngu custom. He described his names as "Mandawuy" means 'from clay'; Djarrtjuntjun means 'roots of the paperbark tree that still burn and throw off heat after a fire has died down'; Yunupingu depicts a solid rock that, having travelled from freshwater, stands in salty waters, its base deep in the earth. I am Gudjuk the fire kite".

Is this is the V100 Mandello’s nearest in concept competitor? More power & heft - but by golly imo it sure does look messy by comparison!

More info... (do yourself a favour & view some of these YouTube video’s on your large screen hi-def TV - I have to admit when you do that the V100 looks awesome! - & sounds great for a stock factory exhaust) 😅

Here you go LP I believe the one you’re after is below... One of the (many) ways I view passive prechamber ignition - is it’s like having the ability of changing the combustion chamber shape in order to improve flame front deflagration efficiencies ...without changing the shape of the combustion chamber! In otherwords - it removes one negative of the hemi chamber shape - whilst keep its benefits. Too strong & harsh tho. Although I’m not yet satisfied that - some or much - of the NVH harshness I’ve experienced isn’t simply because ignition is in effect too advanced for the PPI characteristics Yet with the smaller capacity Heron head Monza - from say 3500-4000 rpm it’s just like boost coming on strong & unleashed it really ups & flys compared to its normal character imo.

Details...

Maserati explains well between 2.50 & 5.00 the benefits of passive prechamber ignition - & also lightly touches on the increased NVH which they’ve overcome by adding a normal spark ignition near the cylinder wall. I’ve actually been pondering on a couple of paths - so I’m going to have another crack with my V11 - but with the accelerated combustion chamber flame speed its power delivery to date is a very raw feeling in its intensity. Wouldn’t be a pain if purely racing - but on the street not so relaxing. Experimenting is not always a smooth path... where you get it right first time!

First vehicle I bought as a seventeen year old was an original (with patina) 1939 Ford pickup small truck with V8 side valve motor, 3 speed, running boards, big bullet lights, split window that an old retiring Italian used for decades carting sandalwood. Loved it! Then I was stoopid...

...which I’ve been experimenting with on my own bikes. There’s power gains to be had absolutely - but the increased NVH harshness levels put me off for now. I don’t get how to knock back the ECU timing to compensate which might help - so with my V11 I’ll return again to this later when able to do so. Not willing to access more power at the expense of more harshness. However, with my V50 Monza the prechamber ignition gives it much more noticeable verve & impetus with just a nice corresponding thrum thru the handlebars. The Monza feels like it’s kinda more awake & willing to rev to redline.

...the limits on upload require separate posts...

I’ve actually been fascinated by the research & development in passive prechamber ignition & its benefits.

https://m.facebook.com/groups/268481854418/permalink/10157102947139419/ 🍿 I too was looking forward to a bit more popcorn 🍿 After all there are many on this forum who are interested in exploring various V11 performance nuggets. Anyhoo... Q: Has anybody dual plugged their V11’s & found the (NVH) harshness level has noticeably increased?