Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > Rockers...

[lane748]

How do I know if they are worn without actually stripping it down? i am assuming that once they start to wear/peel, the valve clearances would be greater, thus creating a tapping sound. I cannot hear anything untoward, but then again, with straight through pipes & these damn nosisy clutches, it would be hard to hear anything!
The other thing that concerns me is the reported loose alternator nut problem. Again, would this show itself up as a noise, or is it a strip down/check it out jobbie?

Its easy to get paranoid about noises when these so much clunking going on!!

[pguenet]

As far as I know (and Nelly shown me) there isn't many ways to see but to take the cams out, then check for any worn out chrome on the rockers. Any tiniest wear is a sign that it needs changing.

A good indication is when you take the covers off to do the clearances. If the cams show little wear being little shiny in the centre but still with their black colour on the outside, this is a good indication that the friction is OK with the rocker. When the rocker wears out, the cam starts wearing out too being shiny all the way.
However this method would only highlight a rocker that has gone already... If it is just on its way and hasn't marked the cam yet, you may be in for a surprise before the next time you open to check (broken rocker = BIG OUCH!! or worn out cams = ain't cheap either!).

Relying on valve clearance to assess dammage could be inacurrate cos it might be the result of of other things. I had quite a build up of monoxide on the valve for instance.

[Marty916]

As mentioned, a visual inspection of the rocker contact surfaces is the only reliable way to verify the rocker condition. If your rockers are shedding their chrome, it may show up as shiny chrome strips or flakes in your oil prefilter screen. If your alternator nut comes loose you'll hear a knocking sound from the left side engine case. You can look into the timing inspection window on the left side and see the flywheel itself wobbling around if the nut comes adrift. The threads on some of the alternator nuts are out of spec from the factory and will not stay tight even with the use of loctite. Nichols Mfg. has a double lock nut system that solves the problem.

[Edited on 30-8-2003 by Marty916]

[nelly]

Because the chrome on the rockers is no more than a few thou' thick, if it does start to flake and lift off the effect on the valve clearances is negligable.
As Philippe says, by the time it gets bad enough to start getting noisy, the rockers will be so badly worn, your cams will be knackered to.
You can get a "visual" indication by looking at the leading edge of the rockers contact patch where the cam hits and you will see the cams' start to lose their black finish, but the only reliable way to inspect them is to pull the cams.
It doesn't take long and isn't too difficult.
The alternator nut is again a pretty easy check.
As Marty says, if it has come off you will be able to see the flywheel moving through the inspection glass, especially when you thumb the starter.
Another "check" is to pull the clutch with the engine running. This makes the "rumble" easier to spot if it's there.
Again, the only reliable way is to pull the engine cover off and check it that way.
There is a new nut available now, which is better, but still not 100%.

[rockhopper]

This is what the little buggers shouldnt look like!!

Paul.

[pguenet]

Well actually you need to change them way before they reach that stage. Any little tiny bit of chrome off and they need changing.

[Felix]

Phil is correct. You NEED to change them when they show wear in the shiny chromed surface going dull or grey, such as shown in the bottom example in the above picture. The other two probably damaged the cams.

[ST4]

Nope, they hadnt damaged the cams.

Paul.

[ST4]

Also all that damage happened in less than 6000 miles. The bike had one shim just before i got it so presumably they looked at the rockers at the same time. I've done about 6000 miles since then so it wouldnt have really been possible to spot the damage any earlier. Its had regular oil changes (Motul 300V) every 2500 miles or so and the only evidence of any problems was a tiny speck of chrome in the strainer the last time i did it.

Paul (rockhopper)