Ducati's use a very different type of valve actuation than most engines. It was purposeful a few decades back as it overcame valve float issues, enabling engines to rev higher. Over time, metallurgy advancements conquered the float issue and motorcycle manufacturers got springs working dependably over 20kRPM.
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They didn't solve valve float by making special springs, then made the valves lighter and move less distance because the cylinders got short and fat. Inertia is what causes the valves to float and you can't overcome inertia by just making the springs stronger, that solution would kill parts and waste horsepower. The Ducati valve train design overcame the inertia problem, it literally slams the valve closed gently.
So now you know the Real reason for the Ducati valve train do you want one, or do you want a mass produced Taiwan built British designed sportbike? Yes parts will absolutely be cheaper on a Taiwan built motorcycle, they use cheaper parts, hence the cheaper price.
Its an Italian designed and largely built race bike :| are you an Italian race bike enthusiast, if yes you will love it,
if no then you will find things to complain about. Probably something small like how little they seemed to care when they wired the horn.
I don't know hat you're trying to tell us
BUT
All Ducatis pre about 1996 used basically the same valves.
28 to 40mm tulip, on a 8mm shaft. ALL of them, from 175cc to 900cc, Desmo or springer. Hair clip or coil springs.
BIG HEAVY things, except for length, the same size valves as a Mopar 426 hemi or 440 wedge motor.
In 1997 they went with a 7mm stem.
The redline on a springer 350 was 9000 rpm, the redline on a 350 desmo is 11,200 rpm
I can bounce off 12000 rpm, without tinging valves, on my 350 with modern RD valve springs.
Nothing changed in the valve train but the metallurgy, and shape of the valve spring.
Ducatis are also known for VERY low stressed valve trains.
Sitting on the shelf beside me is a Ducati 250 springer head that I am going to convert to coil springs. I figure while I'm at it I'll change the valves to 5.5mm stemmed CRF426, to get more port volume.
Big Ducati valves are about $75, the Honda valves are $126 USD.
They didn't solve valve float by making special springs, then made the valves lighter and move less distance because the cylinders got short and fat. Inertia is what causes the valves to float and you can't overcome inertia by just making the springs stronger, that solution would kill parts and waste horsepower. The Ducati valve train design overcame the inertia problem, it literally slams the valve closed gently.
Actually it was springs. Desmo solved problems with springs breaking at high revs. Springs that were strong enough to return valves had a limit of 5000 rpm before breaking down. Springs that were able to keep float in check above 5000 rpm had too short a lifespan to be useful. Vacuum melt technology let the same valve train run up to 12000 rpm before floating.
lighter valves combined with better springs pushed the limits even higher, but lighter valves alone would not have raised rpm limits. Better springs did.
Actually it was springs. Desmo solved problems with springs breaking at high revs. Springs that were strong enough to return valves had a limit of 5000 rpm before breaking down. Springs that were able to keep float in check above 5000 rpm had too short a lifespan to be useful. Vacuum melt technology let the same valve train run up to 12000 rpm before floating.
lighter valves combined with better springs pushed the limits even higher, but lighter valves alone would not have raised rpm limits. Better springs did.
Ducati superquadro spins fast because it has 4.41 inches of cylinder bore and only a 2.39 inch piston stroke.
Compare that to a vintage BSA that has a cylinder bore of 3.34 inches and a longer stroke then bore 3.46.
The short stroke is where those higher revs are coming from and btw BSA 500cc single Goldstar makes its power at 7000 rpm and it was made in 1938. Plus, if your 4-cycle engine is rotating at 12000 rpm your camshaft is only rotating at 6000 rpm because that's how valves work.
been duc-curious as of late, what are the common issues that should be looked at/considered before purchasing?
I've heard the valves on them are a pita and buyers should insist on dealer records? timing belts need regular replacement, remember reading something about gas tank issues(maybe someone can elaborate)?
Also what would cause something like this? Bike looks clean otherwise
What type of Ducati are you looking at, monster? Superbike? Multistrada, diavel.
I can't really speak on the newer ones with higher service intervals, but I have a 2011 monster 796 with 31000kms.
For the most part it has been trouble free. Gas tank issues are abundant but since purchasing I've only used "no ethanol 91" and haven't seen an issue with my tank.
Seems to like eating belts, belt tensioners and front sprocket retaining clips. It's never left me stranded though except once due to the sprocket retaining clip wearing out and shifting the chain into the swingarm. My fault for not checking it early enough.
Valve services were done at Corsas every 12000kms for air cooled monters. So far so good. I also changed the front forks to fully adjustable monster 1100 Evo forks. The stock front forks are terrible for anyone over 160 pounds lol. Just recently replaced the oil cooler upfront due to my negligence and tightening the lines to hard.
Not really riding much the past few years so I can't speak on if anything else is brewing. Is it Toyota Camry reliability? Absolutely not. But it isn't as bad as it's made out to be, I would say average.
I would absolutely recommend a Ducati as a fun bike to ride and would buy one again in a heartbeat. However Aprilia has won me over a bit (tuono) and that would probably be my second bike.
Because they don't need mega strong springs to close the valves, they use mechanical cams and levers to assist with accurately moving the valves.
I swore off ever buying another motor with a rubber belt drive valve train years ago. Give me chains, rods or gears, rubber belt drives are for cheap toys.
Because they don't need mega strong springs to close the valves, they use mechanical cams and levers to assist with accurately moving the valves.
I swore off ever buying another motor with a rubber belt drive valve train years ago. Give me chains, rods or gears, rubber belt drives are for cheap toys.
In some places yes, other no. Desmo has high loads at the cam to rocker connections. This requires hardened rockers with even harder chromed mating surfaces. Many late model Duc designs have rocker arm failures related to wear at the mating surfaces -- and it's quite an expensive repair at $150/rocker arm. The other issues is cam belts -- the constant load taxes belts and they need frequent replacement, where a chain will go for the life of most engines, and belts in cars at least 100,000km, Goldwings at 160,000km -- Ducs at 20,000km.
I predict Audi will nix desmo at some point -- the heritage technology requirement for both HD and Duc has already been stressed past it's practical limits -- at some point conventional heads will prevail.
If you want a good comparison on valvetrain service costs, compare a SV650 engine to a Duc 800. They make about the same HP and Torque, one uses desmo, the other conventional springs. to roll 60,000km, the some Ducs will have cost $2500-3000 in valve service, vs $600 for the SV. Many SV owners gamble and go 70K without checks and adjustments and rightfully so as it's rare to need adjustments even at 70K, AND the risk of catastrophic damage near zero. Not so with a Duc, throw a belt or carbon up the desmo system by skipping services and you're into parts bike territory.
Correct, no springs to overcome -- but they do have a lot of stresses related to the inertia of rocker arms. You can't use rollers (as you see in the spring valves above), that's why the hard chrome the friction surfaces on Duc rockers. If they didn't, the friction related to overcoming rocker inertia would quickly wear the rockers away. Ducati has suffered well known challenges as the hard chroming in some production runs failed prematurely.
I doubt that timing chains adjusters are pretty much automatic. I have an old dirtbike that needs to be adjusted periodically -- I back off a locknut then tighten -- takes all of 30 seconds, no parts come off, just the twist of a 12mm wrench.
I doubt that timing chains adjusters are pretty much automatic. I have an old dirtbike that needs to be adjusted periodically -- I back off a locknut then tighten -- takes all of 30 seconds, no parts come off, just the twist of a 12mm wrench.
Off topic but I’m curious if anyone knows why the 12mm seems to be the red headed step child? I did my rear brake pads today, caliper bolts were 12 mm but none of my 1/2” drives had that socket
Off topic but I’m curious if anyone knows why the 12mm seems to be the red headed step child? I did my rear brake pads today, caliber bolts were 12 mm but none of my 1/2” drives had that socket
Correct, no springs to overcome -- but they do have a lot of stresses related to the inertia of rocker arms. You can't use rollers (as you see in the spring valves above), that's why the hard chrome the friction surfaces on Duc rockers. If they didn't, the friction related to overcoming rocker inertia would quickly wear the rockers away. Ducati has suffered well known challenges as the hard chroming in some production runs failed prematurely.
Ok, now take a look at the parts diagram for your FJR1300.
The DOHC that I showed has roller rocker arms, your bike doesn't you have cams that ride on buckets. That's the cheapest possible way it could be built :| if a Ducati has issues, your Yamaha has the same or worse issues.
Ok, now take a look at the parts diagram for your FJR1300.
The DOHC that I showed has roller rocker arms, your bike doesn't you have cams that ride on buckets. That's the cheapest possible way it could be built :| if a Ducati has issues, your Yamaha has the same or worse issues.
Rollers are used when necessary, needless weight and mechanical parts that are unnecessary in an FJR. It's a light valvetrain that only overcomes the inertia and tension of valve springs up to 9000rpm. Remember, this is a different class of dependability engineering, to compare a Yamaha to a Duc would be like comparing a Fiat to a Toyota. Most FJRS never ever see a valve adjustment in their life, I've seen plenty at 200,000KM that have never fallen out of spec.
In a similarly powered Duc, say a MS1200, the motor has to work faster to make the same hp/torque. The Duc also has to contend with valves and the weight/inertia of rocker arms. That's why they wear and require frequent adjustments and belt replacement.
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Because they don't need mega strong springs to close the valves, they use mechanical cams and levers to assist with accurately moving the valves. 
