Engine noises
 

Hi all,

Could the more experienced guys post some info / description of different engine noises for a 916/748?

How does a piston slap differ from the rockers knock or the main bearings gone noise? What other symptoms appear with the noises and can facilitate the identification of the problem?

I noticed on my 916 a strange knoking sound at around 4000-6000 rpm. It can only be heard while riding and when you accelerate and the rev is around 4000-6000.. I tried to hear the noise while idle, but i couldn't hear it/distinguish it.

thanx

In my humble opinion the Ducati engine is so mechanically noisy anyhow what with the dry clutch and the big exhaust that its very difficult to hear noises that shouldn't be there.

Does the noise go away when you pull the clutch in?

Worn mains make a rumble (well on cars they do anyhow!) DUcatis have roller mains so maybe different. Could it be bodywork or exhaust resonating?

Noise can only be heard while accelerating, if you keep the revs constant or pull the clutch it cannot be distinguished from the exhaust or other loud noises

Dont worry about it till it drops off

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

It won't be the rockers.

Blowing exhaust perhaps.

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

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

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 :)

Just make sure its not your alternator coming loose

Ok i'll try to record it on my mobile :D:D:D:D:D

probally not what you have but..
I had a bloody funny knocking noise comming from what sounded like the front of the bike..found out that the last person to put new wheels and tyres on the bike didnt do the rear nut up enough and the clip was the only thing holding it on..... me not best pleased ...

you can hear plenty if you stick a rag in each exhaust pipe end for a few seconds while you have a listen (sounds like a washing machine full of scrap iron IMHO) :)

I had a loose flywheel last year on the 996 .Rode up the M1 cruising at 90 for 100 miles and I recone it was loose a long time before that. The noise was not that distinguishable as it was progressive but when the bike was checked on a service sure enough the fly was loose. I would say its vibrated more and the noise came from "within",with the noisy clutch most of these "noises"are hidden and difficult to pin down.4D

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

:rodent: "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

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!

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

Or can it be the main bearings?

hello, anyone?

every time i ride mine i hear a different noise so ive now givin up tryin to decide where its comin from(probaly why i lost me stand last year).

I think your stand just wanted to live on a red one!

Hi all, heads were removed from the engine and the guys at Ducati found signs that a metal ring/washer something was inside the horizontal cylinder and was beaten between the cylinder head and the piston. The problem is nothing was found inside so they assumed that whatever it was it was thrown outside on the exhaust...

Piston rings are all fine, so what entered the cylinder definatelly came from the admission...

They checked underneath the tank/fuel pump/throttle bodies and everything is in place..

What do you guys think about this?

Sorry, If I'm picked up any of this wrongly :
this problem only started or was noticed after the bike had been in for work to be done, viz on the throttle bodies/linkage ?
After which you found some evidence of lack of attention to detail - missing seal ? Yes/no ?
Then a foreign body is found in cylinder, - well, call me old fashioned etc, and whilst one wouldn't want to speak on the specifics of this case, one could make a pretty powerful case for the theory that something plopped in to induction when throttle bodies were exposed (airbox removed), - you are very lucky that this apparently did not cause damage - you might want, out of interest, to get compression checks done (if not already) on each cylinder.

Where did the foreign body come from !! It cant get in past filters in normal operation, and it didn't drop off anything inside airbox.....

Very curious, but I guess kind of re-assuring that they found something.

Hi, indeed i cannot confirm or know for sure when this started... but anyway i can tell that i heard the bike one morning doing a strange louder than usual noise, i took it to service where they removed the airbox and cleaned the throttle linkage + checked the top expansion tank.

I took the bike the next day and i noticed a strange distinct metalic sound while revving it around 5000-6000 rpm. This happened only while riding, it was very clear cause it could only be heard only on acceleration,ever on constant throttle or decceleration.

The same evening i had a problem with the throttle linkage, cable, something sticking open, bike revving on it's own so i took it back to service the next day.

They started it the next morning and they noticed a very loud metallic noise at idle, stopped it immediately, started it again, same thing, stop again and the 3rd time it didn't do it anymore.

I arrive at the service the same day and of course nothing could be heard anymore.

Finally decided to start removing the side covers and then the heads/cylinders for further inspection.

the result was the following (sorry for the bad quality photos, did em with my mobile)

Valves are ok, piston rings are ok / cylinder is ok; no sign of the object in the engine/exhaust