Brilliant Various Ducati Tech Articles

[JEC]

Here:

http://ducati-upnorth.com/tech/techlib.php

Articles by Larry Kelley and other Duc gurus on everything from crankcase ventilation to rectifier failure. Invaluable stuff for the mechanically inclined.

[ducaati]

teriffic link, I joined that one, also!

[JEC]

I'm going to post some of the more pertinent ones up as separate threads.

[Chuckracer]

bump

[Drew79]

I was pretty stunned! I was hoping for something insightful and informative, but I'm pretty seriously disappointed.

I only picked two articles, I'm not currently servicing my own bike as its still in warranty but I've been looking at upgrades, so I picked lightened flywheels and carbon fibre wheels.

Lightened flywheels; This article seems to be scaremongering about wheelspin and glosses over or ignores the major benefits in removing drivetrain inertia.

First off, I'm skeptical about the risks outlined within the article, while a lightened flywheel does allow revs to flare more quickly it also means that the engine is more responsive to throttle input, allowing the rider to deal with the problem more rapidly and accurately as well.

Additional to this the author makes a false statement about removing a kilo from the rotating mass of the engine being equivalent to removing a kilo from anywhere else on the bike, this is false. The engine (depending on gear) rotates between 4 and 10 times faster than the rear wheel, the engine inertia is also multiplied by this factor, so in first gear, for instance, removing a kilo from the flywheel would have a significantly greater effect than fitting lighter rims.

Stalling issues were also highlighted as a major drawback... if the engine starts without throttle then stalling by definition can't be an issue at higher RPM. The bike would be markedly more susceptible to rough operation of the throttle but would not spontaneously stall.

Driveline shudder would be reduced as a problem, not increased. Driveline shudder at traffic speed (in my experience) is simply related to slack in the driveline being taken up, then effectively causing a springing effect between the road and the engine, reducing engine inertia would reduce this effect.

Bike turning/Stability would be positively effected by reducing the rotating mass of the engine in exactly the same way as lightened wheels.

Yet another issue poorly misrepresented was the impact of a lightened flywheel on shifting. Lowering the engine inertia means two things; first, it is easier to match revs due to a more responsive engine and second that if you do stuff up it is easier for the rear tyre to accelerate or decelerate the engine, reducing wheel hop.

Another nice benefit of reduced rotational inertia within the engine is less likelihood of compression lockup and reduced effect when it does happen. This is because the compression of the engine can momentarily cause traction loss at the rear wheel, having lower inertia gives the back tyre more hope of getting it back. Its not exactly a slipper clutch, but it helps.

Carbon fibre wheels; This one isn't so much of an essay as being stunned by the fact that this guy seems to be basically exercising xenophobia against a construction material. It stuns me that this guy is crapping on about the fatigue properties of carbon fibre when he's using aluminium or magnesium as the baseline, especially when referring to shock loading or fatigue issues.

[fairplayinc]

Thanks for the link!

[ltsnipe]

thanks for the link, lots of great info

[99duc996s]

very awesome info, will enjoy reading these. thank you

[Ferrolanoman]

a lot of useful information, though--sadly--some of the links no longer work.