Desmo cams accelerate and decelerate the valve without help from a spring, so all the forces are transmitted to the cam drive, and if the nut is not doen up properly, it will allow a tiny bit of movement, which, when you ride, er, enthusiastically, as you have to on a 600, causes a tiny hammering effect, which can only get worse.
A good mechanic will notice this movement when they change the belts, but if corners have been cut, the movement will get worse faster.

oh - re spluttering and lean plug readings - the std airscrew settings are way too lean, you need to screw them out 3 turns from fully in and you will get better idling with less low rpm popping.

Thanks for that. i understand it a lot better now.
Its actually nice to have the head off to get a better idea of exactly what happens when it runs - im used to dealing with 2 stroke systems and less moving parts..

Odd thing.. the nut was tight. It was quite tough to get off today.

Although i got 5 years of service history with the bike, i have found (stupid) things where corners have been cut so anything is possible.
The belts were replaced back in september 05 as were some head internals (but im not sure which head).

Thanks again (to all) for being patient and answering all my Q's.

Cy

unfortunately mine is on the horizontal so its engine out for me- wierd thing is i never noticed any extra rattles or bangs i was just giving it a clean-the cam doesnt look as bad yours cy but i would feel happier with a new one that isnt worn- i have got spare bottom end. barrels and pistons but no spare heads:barfy: belts were done 4000 miles ago-i'll have to wait until next week before i get chance to get the head off to investigate further

That is crazy, Dave !

Still cant beleive the same thing happened to you. It's complete ****bag you have to drop the engine. I guess im lucky in that sense that it was the front cylinder on mine.
The more i think about it, youre right, i will probably have to bite the bullet and go for a new cam.
I saw a spare head with internals on ebay about 3 or 4 weeks ago that didnt sell and was up for £50... kicking myself now for not snagging it for spares.
Really not looking forwards to paying over 200 rubs for a camshaft.

One good outcome is that i have learned a TON today. :lol:

Cy

cy
its a bit of a wierd coincidence isnt it- i maybe caught mine before too much damage was done although the woodruff key isnt a snug fit in the cam - i'll get a new one and see what the fit is like before i go stripping the whole lot out
i was thinking of maybe taking cams to an engineer shop and seeing if it was possible to get the key way and pulley slot machined wider and fit a wider woodruff key- i.e to take out the wear-- maybe one of the more technical afficiniado's on the board maybe be able to advise-- either that or get the lot welded together:D

there are race cams, Ergal pulleys and off set keys available from Ducati Performance but they probably cost an arm and both legs- i dont think they give any more power just smooth out the torque thru out the rev range

then there are some adjustable pulleys available from http://www.veetwo.net/index.asp
i like they're hexagonal pulley nuts! better than the slotted thing as standard

You two got me worried, so when I had my 600 to bits today for a pre-season clean I checked my pulleys. Fortunately both are fine.

Monstermob- I have had problems with loose woodruff keys in the past (many, many years ago on a car alternator) and had an engineering company repair the damage (as I recall they filled the old slot with weld and re-machined it). However, given the very hard nature of the camshaft material and the accuracy required I'm not sure that this is an option for you. Your idea of machining a larger keyway may work, though.

If 750 cams and pulleys are the same, I have a couple of spare complete 750 heads in the garage...........

Paul

mmmm believe it or not - according to ducati workshop manual the cams on the 600 and 750 have the same lift and duration but obviously the valves are bigger diameter--havent had time to fully investigate any further damage i:e valve guides and valves
my machinist mate says the keyway can be widened without too much bother but suggests using vernier pulleys to get the valve timing spot on

But how much do you want to spend :D