Ducati Sporting Club UK > DesmoDue Race Series > DesmoDue - General Questions and Chat > In search of Dallas's Missing ponies

[skidlids]

Originally Posted by skidlids

Hopefully we will soon know if we are any nearer to rounding up some of the lost ponies.
The bike is now up and running on a almost complete different injection system, the only things that haven't changed are the fuel pump, the pressure regulator and the engine temperature sensor.
Now it just needs the PC3 USB fitting and then getting it set up on the Dyno

should all be done just in time for Cadwell

Well its been on the dyno and the ponies were still missing

While waiting for the Dyno day to come around we removed the forks and stripped them, then binned them and put my spare set in, I usually find they work better when they're straight and don't have gouges in the chrome where they pass through the bushing.
Dispite them being fitted with 0.85kg/mm spings they actually tested at 1.2kg/mm due to the amount of binding going on inside the leg as the spring and pre-load spacer tried to compress through a slight bend.

In a final attempt to track down the ponies before Cadwell, I changed the front cylinder head for the one I had fitted to Dallas's engine from last years crashed bike.
And after checking out the head he's been running so far this year I'm glad we did it.

Here is a pic of two exhaust valves, each from 620 DD race bikes with the engines built by the same people, both from the front horizontal cylinder and both have done similar race mileage.

[paynep]

Originally Posted by skidlids

Well its been on the dyno and the ponies were still missing

While waiting for the Dyno day to come around we removed the forks and stripped them, then binned them and put my spare set in, I usually find they work better when they're straight and don't have gouges in the chrome where they pass through the bushing.
Dispite them being fitted with 0.85kg/mm spings they actually tested at 1.2kg/mm due to the amount of binding going on inside the leg as the spring and pre-load spacer tried to compress through a slight bend.

In a final attempt to track down the ponies before Cadwell, I changed the front cylinder head for the one I had fitted to Dallas's engine from last years crashed bike.
And after checking out the head he's been running so far this year I'm glad we did it.

Here is a pic of two exhaust valves, each from 620 DD race bikes with the engines built by the same people, both from the front horizontal cylinder and both have done similar race mileage.

They look bigger than mine

[skidlids]

Originally Posted by paynep

They look bigger than mine

That'll explain your lack of power then
Must be those late Monster 583 Heads you have fitted

[paynep]

Originally Posted by skidlids

That'll explain your lack of power then
Must be those late Monster 583 Heads you have fitted

Oh, I'd zoomed in on the image

Looks like you picked up a dodgy pair of heads then

[bradders]

lets hope that sorts it; be good to see the Porn Star on the top step

[skidlids]

Well none of that worked although he bike was far more rideable at Cadwell partly due to a smoother (Lack of) power curve and the reworked front forks

Even reverting back to last years engine hasn't helped, If anything its lost him another bhp with it now down to 53bhp

Time to Blame the exhaust as its the only thing that we haven't tried and apparently it has been modified since the original Dyno runs, two possibilities here I suppose, the larger diameter tail section could be slowing the gasses down and causing issues or the dimensional change has altered the negative pressure that is reflected back up the exhaust to help scavange the cylinder and is now to much and robbing the inlet charge during valve overlap.

No quick fix as ideally another pipe needs to be fabricated , but in the short term Dallas may try a longer silencer with a smaller diameter core to see what effect that has.