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Old 06-06-2012, 06:26 AM   #91
Bueller
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Quote:
Originally Posted by RedShark View Post
The main justification for the Desmo is to allow higher RPMs - without springs to compress the 'action' IS less draggy - allowing for better mechanical efficiency, but the big deal is that your vavles don't "float" at high engine speeds and run into the pistons. Conventional spring-returned valves have to be protected from too-high cam speeds ( operating a 2x crank speed) because the springs can't keep up at some point and when that happens the valve and piston will try to occupy the same space at the same time. This is bad.

While hardly a big concern for most road riders, having bikes with big V-twin engines and no readline on the tach is always good for a chuckle and then rev-ing them out to well beyond the piston speed where a pushrod motor would gack has it's appeal. Much like the legendary engines in The Vincent bikes - capable of 3x the rpms of other powerplants of it's day - well, remember Horsepower is represented by AREA under the curve, so more RPMs mean more checkered flags.

But the biggest 'feature' to me is the belt-driven cam - sure, it's a pain in the ass replacing those, BUT they are fast & light and when replaced the motor is 'refreshed' unlike any other valve-actuation scheme. Hydraulic chain adjusters just take out the slack and rods & gears all experieince wear - meaning the timing is never quite what is was new.

A Desmo motor with fresh belts, timed and adjusted correctly is as close to fresh motor as you are going to get, and that's pretty cool on a MOTORcycle.

Loved my ST4, - it was easier to ride than my Futura (which was faster) - but I still lust for a Norge and occasionally drool over a for-sale 1200 sport here.

The Desmodromic valve actuation system is too closely associated with the brand for them to abandon it, and heck with the maintenance intervals now published it seems little of an issue for most of thier clientele - seriously, if you can't afford the service, you probably should buy something else anyway.
As has already been said - cams (and valves) operate at half crankshaft speed. Additionally, street bike engines with conventional valve springs are hitting about 17000 rpm with no valve float. Ducati's engines red line several thousand rpm shy of that.

The only reasons I can see for desmo technology nowadays is heritage, and perhaps the ability to run some very steep cam profiles.
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Old 06-06-2012, 06:54 AM   #92
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I have to agree...I know that there may be some advantage in balls to the wall racing machines, but for everyday use, I'd trade the desmo drive train for cheaper maintenance costs. That said, the replacement of belt driven cams with chain in the new Panigale, is a step in the right direction.

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Quote:
Originally Posted by Bueller View Post
As has already been said - cams (and valves) operate at half crankshaft speed. Additionally, street bike engines with conventional valve springs are hitting about 17000 rpm with no valve float. Ducati's engines red line several thousand rpm shy of that.

The only reasons I can see for desmo technology nowadays is heritage, and perhaps the ability to run some very steep cam profiles.
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Old 06-06-2012, 07:28 AM   #93
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I think you forgot about the Breganze Laverda's ;o)

Breganze's, Twins and Triples are extremely easy to work on, very reliable one of the best riding machines on the planet.

I think they fit right in between the Guzzi and Ducati.
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Old 12-10-2012, 08:09 PM   #94
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comparisons

I have long lusted after a Laverda, but being verticly challenged, with a 27" inseam, no way can i stop it at a stoplight. there were 2 for sale this year in OC, Jota's one with a factory build in the motor, hot cams, H/C pistons, couldn't justify just going out to the garage and just listening to them . Am jeealous of all you guys who can throw a leg over some of the taller built bikes. wish i had problems of which bike suited me better. my choice is narrowed down for me ....
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Old 12-11-2012, 02:12 PM   #95
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I've owned both Ducati's and Guzzi's so I guess I can add some input.

I love both marque's and would say they both are addicting to ride. The type of bike you like more the more you ride em.

I'd say I prefer the Guzzi just for the feel. It feels like I'm riding fast even when you aren't breaking too many laws. Plus, it still handles awesome.

The Ducati is often the opposite. Around town speeds feel painfully slow and it is only happy at higher speeds. Of course, these are just the Ducati's I've owned.

Both great bike brands with loads of Italian style and character. I'd love to have a garage full of em.
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Old 12-11-2012, 04:10 PM   #96
PhilB
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I'm definitely a Ducati fan. I like the nimbleness and light weight. I've also always liked Guzzis, but haven't owned one yet. If I need to get a new bike, though, the Griso 8V is on my shortlist. I testrode one and really liked it. I've ridden several other Guzzis over the years and always enjoyed them.

As a few have noted, it depends on your usage and local terrain. I spent many years commuting daily in heavy traffic in SoCal, lanesplitting on a daily basis, so a light narrow bike with instant responses was important to me, making the Duc a better choice than a Guzzi or other heavier bike. Now I'm in rural NH, with less traffic, lots of two-lanes with low speed limits, and bumpier roads. A Guzzi might well be a better choice here (although I'm keeping my Duc for as long as it can reasonably be kept).

Quote:
Originally Posted by rocker59 View Post
I have not criticized Ducati's Desmo valves in any way. Don't plan to. I like the system.

I'm a Ducati fan. I've owned them. I've worked at a dealership that sold them.

What I was taking exception to was the comment earlier about desmo being "cutting edge" technology. It's not. No current valve actuation system in use in a motorcycle is.

You'd need to go to pneumatic, or something beyond what is commonly available in today's IC engines.

Well, part of the problem is that you misinterpreted the comment in the first place. It wasn't that desmos were cutting edge, it was that Ducatis were cutting edge. Ducati has been at the leading edge of electronics for bikes (ABS, TC, riding modes, etc. -- and now electronically adjustable suspensions as well), as well as consistently staying at the forefront with brakes and wheels and other standard components. The Panigale is a cutting edge design with regard to the whole bike's architecture. Guzzis, OTOH, are not cutting edge in anything like the same sense; they rely instead on tradition and slow development and overbuilt quality.

THAT was the comparison being made by the earlier comment. YOU are the one who jumped on the desmo valves subject and created this big red herring and spent a bunch of time arguing against something no one actually said.

Quote:
Originally Posted by DesmoDog View Post
Go back even further. For a 1966 Monza Jr., the range on one tank of gas was listed at 291 miles.
Valve adjustment interval was listed as 310 miles. So basically you were supposed to check the valves every time you filled the tank.

And the Monza isn't even a desmo.

I doubt they'd move a lot more bikes. They'd need to build a new factory first as they can only build about 40k bikes per year to begin with. I think they are planning a new factory(?) but for now the question seems to be how many of each model to build, not how many to build in total. They're at capacity now. Why introduce more complexity (different designs, more part numbers, new tooling, etc) to sell a lot more bikes when they can't build a lot more bikes to begin with?

They aren't for everyone. They don't need to be.

I'm not a huge fan of desmodromics. Some of my Ducatis have them, some don't. I don't much care either way. But having worked on them I'd say that the majority of the mystery surrounding them is perpetuated by people with zero hands-on exeprience. Checking/adjusting them isn't rocket science. Are they different than what most people are familiar with? Of course. Do they require tools that arent' included in the Craftsmen master set from Sears? Yes. Are they as complicated as some people would lead you to believe? No. FWIW I'll take the "complexity" of a desmo valvetrain over the philips head fasteners the Japanese seem(ed) so damn fascinated with any day of the week. But that's more of a vintage bike thing...

If you're going to have only one bike, that you ride 12,000 miles each year, and you hate doing maintanence, than no, a Ducati most certainly isn't for you.

I love Ducatis but fully understand they aren't the rational choice. So what? I live in Michigan. I've got multiple bikes, a long winter, and tools that Sears doesn't sell.

I also have a degree in aerospace engineering so even if adjusting desmo valetrains was rocket science I'd be ok, but that's beside the point.
+1 and well said.

Although I have basically only one bike (I have some old scooters, but those are toys, not transport), and I ride it about 11K a year and have been doing so for 19 years, and I hate doing maintenance, and I've been really happy with my Ducati.

As far as the valve intervals go, when I bought mine, new in 1993, it was recommended to check the valves every 3K miles. A few years later, the recommendation was changed to 5K miles, with no technical changes. A few years after that, they made a couple of minor upgrades and changed the interval to 6K miles, then to 7.5K with no further changes. The new Ducatis are split between having a 7.5K interval and a 15K interval. On my bike, I had them checked every 5 to 6K for a while, but once I got past about 30K miles, everything settled in well and stopped changing much, so each check came up about the same as the last one. After 40K, I doubled the interval, and have been checking every 10-12K (about once a year for me), and an actual adjustment needs to happen about once every two checks.

My Duc is a 1993 (first year) M900 Monster, and it's been stunningly reliable and durable. I have had to put some money into it the last couple of years, as it approached 200K; by a rational economic calculation I might have been better off letting it go at 175K and getting something newer. But even so, what it's needed hasn't been the deep basic stuff. The bottom end and transmission haven't seen the light of day since it was built. The alternator bearing failed at 122K and I put in new piston rings at that point. The clutch basket I replaced at 140K. More recently I've had to replace the original carburetors and rear shock, rebuild the forks, get new master cylinders and replace the clutch actuation system, and do a bit of work on the electricals and various gaskets and seals. I don't think that's excessive given the time and distance it has covered for me.

PhilB
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Old 12-11-2012, 05:52 PM   #97
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I think the other thing that has not been mentioned, the duc has a motor orientation that makes checking the valves a lot of work no matter what kind of system it uses.

I checked and changed one valve on my wife's 696, not too bad, but I have to wear reading glasses now (66) and that adds to the difficulty.

I had the Multi12 standard 2010 for 13 months and 9K+ miles. I hated the feeling that I needed to keep in mind what the nearest dealers service department was doing all the time. 2 week back log most of the time. 200 miles away.

It is ironic or maybe not, that the bike (duc) that requires the most dealer attention has fewer dealers, and the Super Ten which has dealers on every corner, I never been in!

The Goose was not on my radar, maybe I need to take a look.

For the OP tho, I still miss being able to pass anything on wheels just about anytime I wanted to on the Multi12! That was fun, just roll on in 6th or if in a hurry drop down to 5th, and you were gone.

I have a local stretch I run up sometimes, on the Multi12 I would get to 105ish in 4th or 5th then down shift to normal breaking to a 90 degree 55mph curve. I did the same run on the Super Ten, feels about the same but it tops out about 85ish before I have to toss out the parachute. The Multi12 will get down the road very quickly!
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