Total Motorcycle Community Forums

Snake wrote:Extreamly expensive maintaining one, you can't do the valve adjustments, and the shop charges 700-800 bucks for every adjustment. not to mention the 30,000 price on the 999.

I pay $450 Canadian. It's my wifes bike and doesn't see all that many miles so it's not a big deal.

This guy would certainly be looking at alot depending on the distance of the commute.

The weight distribution of a Duck is unlike anything I've ever felt -- perfectly balanced. The 750 Monster felt like a 500 to me.

But -- I agree the riding position can be uncomfortable after long periods. In addition, (someone correct me if I'm wrong) those are hand-built imported bikes, are they not? They're naturaly going to cost more in all aspects -- cost, maintenance, parts, etc.

TechBMW wrote: What makes Ducati's valve check interval so short is the fact that Ducati uses a wire circlip on the valve to keep it from falling into the cylinder. This must be changed every 6,000 miles in order to prevent this from happening.

Why did they do this? Less mass for the valvetrain? Seems like a silly, problem-prone way to keep the valves from meeting the pistons at high velocity.

Skier wrote:

TechBMW wrote: What makes Ducati's valve check interval so short is the fact that Ducati uses a wire circlip on the valve to keep it from falling into the cylinder. This must be changed every 6,000 miles in order to prevent this from happening.

Why did they do this? Less mass for the valvetrain? Seems like a silly, problem-prone way to keep the valves from meeting the pistons at high velocity.

Because they're Italian. And no one tells an Italian that they don't do things right. I know. I'm married to one

It may have something to do w/ less mass... probably does as a matter of fact. These things don't fail often, the valve check intervals are just a precaution. And Ducatis aren't the only ones who need valve checks this often ... look at some japanese bike requirements and you might be surprised..

At least the valve adjustments on a Japanese bike are not too tough to do.

How does the Desmo valve system even work? If I recall it doesn't use valve springs at all but some kind of counterweight system.

Funny part is many Japanese cars use the same valve adjustment procedure as a Japanese bike, especially hondas, I know the valves on my wife integra have to be adjusted every 10k or so and its much more time consuming than the 5 min adjustment procedure on my VW.

jmillheiser wrote:At least the valve adjustments on a Japanese bike are not too tough to do.

Depends on the bike. A 20 year old bike is simple ... newer ones (like the ones w/ VVT) are killer.

Normal overhead valvetrains have a lobe on the cam which presses down on the valve (Or rocker arm) to open the valve. These setups rely on a spring to close the valve. At really high revs, this can result in valve float (The valve doesn't fully close because the spring can't return it fast enough) With todays materials, this really isn't a problem.

However, the Desmodromic valve system allows no float. It has two lobes on the cam, and 2 rocker arms per valve. One opens the valve and the other one closes the valve. Ducati uses shims for proper spacing on the valves, so you have to check the closing shim and the opening shim.

You check the valves like any other bike, with the piston at TDC, except that you press down on the closing rocker arm (With a screwdriver or special tool) so you can check the gap on the closing shim.

Basically, this takes an extra minute or two per valve. It's really nothing major at all.

Here's a link to how desmo works http://www.ducati.com/bikes/techcafe.jh ... =technical

Here's a link to how to check desmo valves
http://www.ducatitech.com/2v/maint/adjust/

This info is pertaining to the 2 valve models. 4-valve models are basically the same, but the procedure is a bit more complicated. One of the Nice things about Ducatis is that they still have plates over the valves to make it easier to do a valve check. you don't have to remove the whole valve cover (like on an inline four) to do it.

Basically - when you take a Duck in for a valve check, you are really paying for the guys to take off all the body work and whatnot to gain access to the valves. the valve check itself really isn't that time consuming once you have it down. Ducati service people take advantage of the fact that Desodromics is this mysterious thing that people are afraid to deal with ... therefore they can jack up the price for this easy procedure.

jmillheiser wrote:At least the valve adjustments on a Japanese bike are not too tough to do.

How does the Desmo valve system even work? If I recall it doesn't use valve springs at all but some kind of counterweight system.

Funny part is many Japanese cars use the same valve adjustment procedure as a Japanese bike, especially hondas, I know the valves on my wife integra have to be adjusted every 10k or so and its much more time consuming than the 5 min adjustment procedure on my VW.

I haven't seen a car that requires valve shims before, and both my bikes ('86 Yamaha Radian, '89 Suzuki Katana 600) both take shims to adjust the valves.