Those sound deadening bungs between the fins ?

[utopia]

What's the group experience on the change in sound if you remove them ?

I'm currently deep cleaning the snotty bits of my engine.
Its nearly a year overdue to be honest, following a couple of trips on very salted roads last february.
Obviously I did wash the bike straight away, but the damn stuff gets deep into all the nooks and crannies where it defies access during routine cleaning.

Anyway, I'm currently scrubbing between the fins of the front cylinder and those bungs are a royal pain.
They're dirt traps as well as barriers to one's spoutbrush.
I don't think they help the cooling either.
I'm almost certainly going to remove them but before I do I thought I'd consult the oracle.
There must be a few who have repainted their engines and decided not to bother replacing them ..?
Did you notice any difference in sound ?

Not that I mind a bit of sound anyway, you understand.
Its a Ducati after all.
We like a bit of mechanical noise.

What sound do we think they deal with ?
"Ringing" from the fins ?
Or that "tinking" that I fondly recall from the 2-stroke days ?


Btw.
I have discovered that an Aldi Dremel clone equipped with one of those black nylon brushes, used on ultra slow speed with copious squirts of GT85 will get right into the pores of the engine paint (that still remains !) and restore amazing freshness to the finish.
I've been using the cup brushes mostly for larger areas but the little pencil ones are also handy in the tight corners or up against casting flashes.
Some areas need a second or third attempt as the more baked on grime softens.
And a spare day or two.

[Mr Gazza]

What a coincidence. I was stripping the bike out for a valve service earlier this evening and noticed one of the fin bungs sitting on top of the fin next to the spark plug on the vertical head. It seems to have just slid out??
It was rather hard, not resilient at all, as thought it would be.
I tapped it back under the fin with a screwdriver.

I don't think they are of huge importance although obviously there for a reason.
They must damp some resonance.. probably not when they are hard like mine though?
I think most of them have dropped out anyway!

I don't think they will adversely effect cooling, The engines over cool as it is.

I see no reason why you couldn't knock them out for cleaning and then knock them back in again, or not.

[Davy]

All mine are in a jar after replacing all the cylinder head studs and painting the engine I’ve not noticed anything different so they will stay in the jar..

[bigredduke]

My understanding is that they are supposed to dampen any ringing sound.

I think, if you remove them, you will find that fins ain't what they used to be.

[Dukedesmo]

I removed mine when I first bought the engine and stripped it for a rebuild/paint so I've never had them in during my Monster ownership.

Can't comment on before/after noise as I never heard it before and it's pretty loud anyway but I don't think the rubber things make any difference?

IMO they must impede (albeit probably only very slightly) airflow and so can't help with cooling?

[Flip]

Yep, same here- for what seemed like every time I stopped I would look down to see another one of those was on the floor next to my bike and each time I picked one up it would be rock hard.

That was several years ago now and the ones I picked up are in a pot in my garage and the rest dotted around either the UK or Western Europe.

A quick Google on their purpose says they help reduce sinusoidal resonance of the cooling fins at or near the engine's mean torque peak piston velocity that can cause rider fatigue and a ringing sound depending upon the state of a person's hearing.

So why Ducati chose to fit them with the ring-a-ding of a dry clutch coupled with open pipes so many of us love I have no idea and with the open air box on my 900 as well I am certainly not going to be able to tell if they're in or out.

[Tim88]

I thought it may be just me. I have been picking them up from my 'driveway' for the last few years. My key jar in the kitchen now has nine of the things. Looking at them now four of them have holes in the centre and the rest are solid and slightly thicker. I am waiting for the rest to be shed naturally but I may help a few on their way at next bathtime.

[utopia]

Yes, two or three of mine have popped out over the years.
The first one had me guessing for a while.

Anyway, I've hoicked them out.
A spring puller was the tool for the job.

It seems they're only in the head fins, not the barrel ones.
Since both are of almost identical form, I'd say that's a half hearted attempt at best.



ps.
They weigh 1.7g each and I removed 15 of them.
That's a 25g weight saving.

[utopia]

Originally Posted by Mr Gazza

I don't think they will adversely effect cooling, The engines over cool as it is.

Hmm .. not sure that I agree.
Maybe the engines do overcool in winter (the more so if they have an oil cooler) but during the heat of an Italian summer, I would be happier if all of the fins were open to the airflow, particularly in slow moving traffic.

[Darren69]

IMO The real issue is that due to the engine layout the 2 cylinders run at different temperatures with the rear one always that bit hotter than the front one because its not in the airflow as much. So with carb bikes there is never an ideal.

On my S4 I have found that there are 2 temp sensors for front and rear cylinders and as far as I can tell the the front one just feeds the dashboard temp readout and when fans cut in but its the rear one that feeds the ECU in order to correct the fuel map.

[Darren69]

Oh and regarding those rubber pucks in the fins I think you can ditch them without any detrimental effects. When I had air cooled Ducati bikes with them they pretty much all dropped out eventually anyway as others have said.

[utopia]

Originally Posted by Darren69

IMO The real issue is that due to the engine layout the 2 cylinders run at different temperatures with the rear one always that bit hotter than the front one because its not in the airflow as much.

Yes.
I fitted some carbon airscoops (purchased via this very forum) in an attempt to grab more air for the rear cylinder, but their function is hampered, on two counts.
Firstly, I reckon they need an internal moulding to direct the flow more effectively than they currently do ... that job's been on the backburner for years.
Secondly, you look down one scoop and what do you see ? .... the tuna-can vacuum fuel pump, flat on to the flow.
So ... the eventual plan is to fit an injection style tank with internal pump.
I have said tank (in carbon fibre, no less) complete with pump, awaiting installation.
I also have a set of FCRs to go on as part of the same deal.
But I don't want to fit those until the new single-can exhaust is restored and fitted, so I can get the whole caboodle dyno'd.
Only after that lot am I likely to rework the airscoops.
Of course that will be a bit "after the horse has bolted" because the engine will be 30,000 miles old by then and I'm guessing that the extra bore wear will have already been done.
But its about engineering principle, aint it ?

I've not looked closely but it looks like the rear cylinder has no damper bungs ... but it has bigger, lateral fins (with, presumably, a lower resonant frequency) while the front cylinder's longitudinal fins are super short.

My hope is that Ducati only fitted them as a sop to noise limit regulations, and that this was a trade off which enabled them to get away with louder exhausts.

[Darren69]

Sounds like a nice project! I too have a carbon tank yet to be painted and fitted (worried about ethanol fuel and what treatment to give the inside) but I can comment that I have noticed that the air scoops do make a difference on my S4 as the temp seems to drop faster when on the move, maybe they could be improved with some internal moulding as the later SS models had but I don't have one of those carbuncle fuel pumps in the way.

No doubt the design could be improved but they do work in a rudimentary way and combined with the DP oil cooler which I fitted makes the bike run 10-15% cooler and cool more quickly. I can't understand why the S4 didn't get an oil cooler as standard in the first place, its a 916 engine after all and the fairing on the 916 is designed to channel the cooling air in much the same way as the air scoops do.

[utopia]

That's useful info on the scoops.
I had never considered their fitment to a water cooled model.
And I think I'm going to deduce that, if their effect is noticeable on a water cooled motor (and somewhat verifiable, as there are temp gauges in the mix) then their effect is likely to be even greater for an air cooled motor.

On the carbon tank, Capo has been running one for years on his S4R.
I'm not certain but I don't think he treated the inside.
Then again, he's fastidious enough that he probably rarely leaves fuel sitting in the tank over winter.
I've not done much research yet myself.
Tbh I'm dithering because one downside of the carbon is that my magnetic tankbag will no longer stick ... and I do need a tankbag.

[utopia]

Originally Posted by utopia

I've not looked closely but it looks like the rear cylinder has no damper bungs ... but it has bigger, lateral fins (with, presumably, a lower resonant frequency) while the front cylinder's longitudinal fins are super short.

A quick and relatively insignificant correction here, but ....
Having had a closer look, there are about the same number of damper bungs in the rear cylinder fins as there are in the front.
..... a theory too far then.
It wont have been the first time.