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

[CipiVTS]

The only thing i'm worried is what if it's the rockers and i can still do something.
From what i understood rockers have a lighter metallic sound?

For the others... God knows

[rockhopper]

It won't be the rockers.

Blowing exhaust perhaps.

[CipiVTS]

Exhaust i doubt, cause the sound is metallic (not steel / steel like but more alluminium knocking type) and comming definatelly from the engine (front).

The bike was in service to change the rear eccentric hub and the sprocket flange which were complettely knackered and the back wheel was almost blocked.

The first thing i noticed when i took it yesterday was how freely and smooth it went and of course this noise i haven't heard till then.

In service i put them to grease the throttle cable, the throttlebody linkage system and to check the water expansion tank which was leaking.

Because they removed the airbox, i assumed they probably forgot to fit an air filter (BMC) so i checked yesterday. Hopefully everything was in place, only the top cylinder air funnel is moving and doesn't have an o-ring

[Jools]

Originally Posted by CipiVTS

Exhaust i doubt, cause the sound is metallic (not steel / steel like but more alluminium knocking type) and comming definatelly from the engine (front).

Because they removed the airbox, i assumed they probably forgot to fit an air filter (BMC) so i checked yesterday. Hopefully everything was in place, only the top cylinder air funnel is moving and doesn't have an o-ring

I would say that's your answer. Let's consider the facts...

"Oi...how did Lloyd Grossman get in here".

Aluminium type tinkling sound, coming from the front, only happens at certain revs, intake trumpet loose and without o-ring.

I would say it's the intake trumpet resonating at certain revs. Above or below those revs the induction frequency sort of keeps it pinned

[CipiVTS]

Hi all, thanks for your answers, but i guess it's not that.

after leaving the bike outside for 3 days without starting it (temp ~10 deg C) i started it on Friday last week and i had to stop it immediatelly because of a very loud metallic knock coming from the engine. Left it for 1 minute, started it again and the same thing. The 3rd time started ok without any sound... The 4th time it did the knocking again and i decided to let it run, after 5 secs it dissapeared and was ok afterwards. Took it in the same day to Ducati and left it there for a brake check up and cylinder balancing. They started it this morning (after 4 days not started; kept inside temp 17 deg C) and the same loud knocking sound as last week appeared.

I wasn't there but the guys called me to listen for it. The 3rd time they started it the sound dissapeared after a 5-10secs they warmed it up did the cylinder balancing and waited for me to come to listen it. Of course when i came to the service there was no knocking...

What can it be?
Their initial assumption is that it's a piston bolt and the piston is knocking the cylinder head or the valves.... but they didn't crack it open yet

Help!

[ducv2]

Take it the cambelt has'nt jumped a tooth? I suppose that the noise would be permanent rather than intermittent

[CipiVTS]

Or can it be the main bearings?

[Douglas]

Also maybe its the induction noise,which can be pretty loud when you accelerate hard at lowish revs?

[phil_h]

Sounds like it could be an induction noise at that kind of revs.
I think you should do some recording for us so we can all have a listen

[ducv2]

Just make sure its not your alternator coming loose